Hubble Sees Unexplained Brightness from Colossal Explosion

 

NASA & ESA - Hubble Space Telescope patch.

Nov. 14, 2020

Long ago and far across the universe, an enormous burst of gamma rays unleashed more energy in a half-second than the Sun will produce over its entire 10-billion-year lifetime. In May of 2020, light from the flash finally reached Earth and was first detected by NASA's Neil Gehrels Swift Observatory. Scientists quickly enlisted other telescopes — including Hubble Space Telescope, the Very Large Array radio observatory, the W. M. Keck Observatory, and the Las Cumbres Observatory Global Telescope network — to study the explosion's aftermath and the host galaxy. It was Hubble that provided the surprise.

Image above: This image shows the glow from a kilonova caused by the merger of two neutron stars. The kilonova, whose peak brightness reaches up to 10,000 times that of a classical nova, appears as a bright spot (indicated by the arrow) to the upper left of the host galaxy. The merger of the neutron stars is believed to have produced a magnetar, which has an extremely powerful magnetic field. The energy from that magnetar brightened the material ejected from the explosion. Image Credits: NASA, ESA, W. Fong (Northwestern University), and T. Laskar (University of Bath, UK).

Based on X-ray and radio observations from the other observatories, astronomers were baffled by what they saw with Hubble: the near-infrared emission was 10 times brighter than predicted. These results challenge conventional theories of what happens in the aftermath of a short gamma-ray burst. One possibility is that the observations might point to the birth of a massive, highly magnetized neutron star called a magnetar.

"These observations do not fit traditional explanations for short gamma-ray bursts," said study leader Wen-fai Fong of Northwestern University in Evanston, Illinois. "Given what we know about the radio and X-rays from this blast, it just doesn't match up. The near-infrared emission that we're finding with Hubble is way too bright. In terms of trying to fit the puzzle pieces of this gamma-ray burst together, one puzzle piece is not fitting correctly."

Without Hubble, the gamma-ray burst would have appeared like many others, and Fong and her team would not have known about the bizarre infrared behavior. "It's amazing to me that after 10 years of studying the same type of phenomenon, we can discover unprecedented behavior like this," said Fong. "It just reveals the diversity of explosions that the universe is capable of producing, which is very exciting."

Light Fantastic

The intense flashes of gamma rays from these bursts appear to come from jets of material that are moving extremely close to the speed of light. The jets do not contain a lot of mass — maybe a millionth of the mass of the Sun — but because they're moving so fast, they release a tremendous amount of energy across all wavelengths of light. This particular gamma-ray burst was one of the rare instances in which scientists were able to detect light across the entire electromagnetic spectrum.

Image above: This illustration shows the sequence for forming a magnetar-powered kilonova, whose peak brightness reaches up to 10,000 times that of a classical nova. 1) Two orbiting neutron stars spiral closer and closer together. 2) They collide and merge, triggering an explosion that unleashes more energy in a half-second than the Sun will produce over its entire 10-billion-year lifetime. 3) The merger forms an even more massive neutron star called a magnetar, which has an extraordinarily powerful magnetic field. 4) The magnetar deposits energy into the ejected material, causing it to glow unexpectedly bright at infrared wavelengths. Image Credits: NASA, ESA, and D. Player (STScI).

"As the data were coming in, we were forming a picture of the mechanism that was producing the light we were seeing," said the study's co-investigator, Tanmoy Laskar of the University of Bath in the United Kingdom. "As we got the Hubble observations, we had to completely change our thought process, because the information that Hubble added made us realize that we had to discard our conventional thinking, and that there was a new phenomenon going on. Then we had to figure out what that meant for the physics behind these extremely energetic explosions."

Gamma-ray bursts — the most energetic, explosive events known — live fast and die hard. They are split into two classes based on the duration of their gamma rays.

If the gamma-ray emission is greater than two seconds, it's called a long gamma-ray burst. This event is known to result directly from the core collapse of a massive star. Scientists expect a supernova to accompany this longer type of burst.

Hubble Space Telescope (HST). Animation Credits: NASA/ESA

If the gamma-ray emission lasts less than two seconds, it's considered a short burst. This is thought to be caused by the merger of two neutron stars, extremely dense objects about the mass of the Sun compressed into the volume of a city. A neutron star is so dense that on Earth, one teaspoonful would weigh a billion tons! A merger of two neutron stars is generally thought to produce a black hole.

Neutron star mergers are very rare but are extremely important because scientists think that they are one of the main sources of heavy elements in the universe, such as gold and uranium.

Accompanying a short gamma-ray burst, scientists expect to see a "kilonova" whose peak brightness typically reaches 1,000 times that of a classical nova. Kilonovae are an optical and infrared glow from the radioactive decay of heavy elements and are unique to the merger of two neutron stars, or the merger of a neutron star with a small black hole.

Magnetic Monster?

Fong and her team have discussed several possibilities to explain the unusual brightness that Hubble saw. While most short gamma-ray bursts probably result in a black hole, the two neutron stars that merged in this case may have combined to form a magnetar, a supermassive neutron star with a very powerful magnetic field.

"You basically have these magnetic field lines that are anchored to the star that are whipping around at about a thousand times a second, and this produces a magnetized wind," explained Laskar. "These spinning field lines extract the rotational energy of the neutron star formed in the merger, and deposit that energy into the ejecta from the blast, causing the material to glow even brighter."

Kilonova Fade-out

Video above: These two images taken on May 26 and July 16, 2020, show the fading light of a kilonova located in a distant galaxy. The kilonova appears as a spot to the upper left of the host galaxy. The glow is prominent in the May 26 image but fades in the July 16 image. The kilonova's peak brightness reaches up to 10,000 times that of a classical nova. A merger of two neutron stars — the source of the kilonova — is believed to have produced a magnetar, which has an extremely powerful magnetic field. The energy from that magnetar brightened the material ejected from the explosion, causing it to become unusually bright at infrared wavelengths of light. Video Credits: NASA, ESA, W. Fong (Northwestern University), T. Laskar (University of Bath, UK), and A. Pagan (STScI).

If the extra brightness came from a magnetar that deposited energy into the kilonova material, then within a few years, the team expects the ejecta from the burst to produce light that shows up at radio wavelengths. Follow-up radio observations may ultimately prove that this was a magnetar, and this may explain the origin of such objects.

"With its amazing sensitivity at near-infrared wavelengths, Hubble really sealed the deal with this burst," explained Fong. "Amazingly, Hubble was able to take an image only three days after the burst. Through a series of later images, Hubble showed that a source faded in the aftermath of the explosion. This is as opposed to being a static source that remains unchanged. With these observations, we knew we had not only nabbed the source, but we had also discovered something extremely bright and very unusual. Hubble's angular resolution was also key in pinpointing the position of the burst and precisely measuring the light coming from the merger."

Black Holes, Neutron Stars, White Dwarfs, Space and Time...

Video above: Simulation of big events of the Universe, Music: Rob Dougan - Château.

NASA's upcoming James Webb Space Telescope is particularly well-suited for this type of observation. "Webb will completely revolutionize the study of similar events," said Edo Berger of Harvard University in Cambridge, Massachusetts, and principal investigator of the Hubble program. "With its incredible infrared sensitivity, it will not only detect such emission at even larger distances, but it will also provide detailed spectroscopic information that will resolve the nature of the infrared emission."

The team's findings appear in an upcoming issue of The Astrophysical Journal:
https://iopscience.iop.org/journal/0004-637X

The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, in Washington, D.C.

Related links:

James Webb Space Telescope (JWST): https://webbtelescope.org/

Hubble Space Telescope (HST): https://www.nasa.gov/mission_pages/hubble/main/index.html

Images (mentioned), Videos (mentioned), Text, Credits: NASA/Lynn Jenner/GSFC/Claire Andreoli/STSI/Ann Jenkins/Ray Villard/Northwestern University/Wen-fai Fong/University of Bath (UK)/Tanmoy Laskar.

Greetings, Orbiter.ch

Space Station Science Highlights: Week of November 9, 2020

 

ISS - Expedition 64 Mission patch.

Nov. 14, 2020

Scientific investigations conducted aboard the International Space Station the week of Nov. 9 included examining how spaceflight affects plant growth, the properties of molten metal, and the human body. Crew members also prepared for the arrival of four Commercial Crew astronauts scheduled to launch Nov. 14 aboard a SpaceX Crew Dragon spacecraft. The Dragon also carries new scientific investigations to be conducted by the expanded crew.

Image above: This image captures Earth's limb or horizon as the International Space Station orbited above the north Pacific Ocean near Alaska's Aleutian Islands. Image Credit: NASA.

The space station has been continuously inhabited by humans for 20 years and has supported many scientific breakthroughs during that time. The orbiting lab provides a platform for long-duration research in microgravity and for learning to live and work in space, experience that supports Artemis, NASA’s program to go forward to the Moon and on to Mars.

Here are details on some of the microgravity investigations currently taking place:

Radish harvest time

Animation above: NASA astronaut Kate Rubins harvests samples from radishes grown for the Plant Habitat-02 investigation into how microgravity affects plant growth. Animation Credit: NASA.

Plant Habitat-02 cultivates radish plants (Raphanus sativus) to determine the effects of space on their growth. This model plant is nutritious, has a short cultivation time, and is genetically similar to Arabidopsis, a plant frequently studied in microgravity. Developing the capability for food production in space requires understanding the effects of conditions such as intensity and spectral composition of light and the culture medium or soil. This research contributes to developing a reliable method for growing food crops to sustain crews on long-duration space exploration missions, including to the Moon and Mars. During this week, crew members collected leaf samples for analysis.

Measuring molten materials

Image above: The Round Robin investigation of the properties of molten metal in microgravity operates in the Electrostatic Levitation Furnace (ELF), shown in this image. Image Credit: NASA.

The crew exchanged sample holders in preparation for the upcoming return to Earth of Round Robin investigation after a 30-day run. Round Robin, developed by the Japan Aerospace Exploration Agency (JAXA), measures characteristic properties of molten metals in microgravity. Results could provide researchers with a better understanding of how to measure these properties and lead to improved models of fluid flow to support design and production of advanced spaceflight systems. Some of the materials investigated are currently used in a wide range of space hardware while others are new materials that could be used to make better devices for future exploration and colonization missions.

Comprehensive data on astronaut adaptation

Image above: NASA astronaut Kate Rubins works on research hardware inside the Japan Aerospace Exploration Agency (JAXA) Kibo laboratory module. Image Credit: NASA.

Data on how crew members respond to life in microgravity are essential to mission success now and in the future. Standard Measures collects a set of consistent measurements from U.S. crew members to help characterize the effects of living and working in space. Taken before, during, and after missions, these measures help ensure consistent data capture throughout the space station program. In addition to characterizing adaptive responses to living in space, the data create a repository used to monitor the effect of countermeasures and interpret health and performance outcomes. Data collected include information on behavioral health and performance, immunology, microbiology, biochemistry, and sensorimotor and cardiovascular status. Crew members collected various biological samples for the investigation during the week.

Other investigations on which the crew performed work:

- The ISS Experience uses footage filmed by astronauts to create a virtual reality (VR) series documenting life and research aboard the space station.
https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7877

- Radi-N2, a Canadian Space Agency investigation, uses bubble detectors to map the neutron environment aboard the space station and better define the risk posed to the health of crew members.
https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=874

- GRIP, an investigation from ESA (European Space Agency), studies the ability of a subject to regulate grip force and the trajectory of upper limbs while manipulating objects, interactions between the brain and external cues, and the adaptations made to grip force and movement coordination in microgravity.
https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1188

- Food Acceptability looks at how the appeal of food changes during long-duration missions. Whether crew members like and actually eat foods directly affects caloric intake and associated nutritional benefits.
https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7562

Space to Ground: Dragon Quest: 11/13/2020

Related links:

Expedition 64: https://www.nasa.gov/mission_pages/station/expeditions/expedition64/index.html

Plant Habitat-02: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7793

Round Robin: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=8016

Standard Measures: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7711

ISS National Lab: https://www.issnationallab.org/

Spot the Station: https://spotthestation.nasa.gov/

Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/overview.html

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

Animation (mentioned), Images (mentioned), Video (NASA), Text, Credits: NASA/Michael Johnson/John Love, ISS Research Planning Integration Scientist Expedition 64.

Best regards, Orbiter.ch

MADMAX and CERN’s Morpurgo magnet

 

CERN - European Organization for Nuclear Research logo.

Nov. 14, 2020

A new collaboration, MADMAX, will seize the chance to use a CERN magnet named Morpurgo to test their dark-matter prototype

Image above: The Morpurgo magnet, located in the North Area on the Prévessin site, will provide a magnetic field of up to 1,6 Tesla for the MADMAX prototype (Image: CERN).

MADMAX is preparing for a stopover at CERN from 2022. Mel Gibson, his artillery and quest for revenge will not be there, but instead a handful of physicists armed with an aged magnet will be searching for dark matter in CERN’s North Area (not to be confused with a post-apocalyptic wasteland).

Indeed, the MADMAX collaboration (MAgnetized Disks and Mirror Axion eXperiment, external to CERN), humbly proposes to identify the nature of dark matter and to solve the enigma of the absence of so-called charge-parity (CP) symmetry violation in the strong sector, while detecting a particle that has eluded physicists for decades: axions.

To do so, the collaboration has developed a brand-new concept using a booster composed of dielectric disks and mirrors. The booster acts as a resonator to amplify the photon flux that axions would produce under a magnetic field, if these axions exist. In order to validate the concept, a prototype needs to be tested under a magnetic field before the launch of the experiment, planned to be located at DESY in Germany.

Although such a magnetic field is difficult to obtain, the collaboration can rely on CERN's assistance. On 16 September, CERN's Research Board agreed that the MADMAX prototype could use an old magnet previously used by the ATLAS experiment. The “Morpurgo” magnet is located in the North Area and generates a field of up to 1.6 Tesla. It is one of the first superconducting magnets to be used at CERN. More than 40 years after the NA3 (North Area 3) experiment first used it in 1978, this sturdy magnet still tests ATLAS subdetectors. MADMAX physicists will jump in to mount and test their prototype during the inter-beam period, when ATLAS is not using the magnet. A solution that suits everyone: for MADMAX, a magnet that meets the prototype's criteria is provided free of charge, and for ATLAS, the space around the magnet is reorganised and optimised, which is necessary for the installation of the prototype.

The recycling and repurposing of equipment is common at CERN, in the spirit of pragmatism and sustainability. With successive generations of equipment, state-of-the-art accelerators go on to become injectors for their successors, and old magnets are reused for new experiments. This is the case, for example, with the CAST experiment, which uses an old LHC dipole prototype in its search for, once again, axions.

However, allowing external researchers to use CERN equipment, as in the case of MADMAX, is far from trivial. According to Pascal Pralavorio, the MADMAX contact person at CERN, this helps to develop new ideas: "Today, particle physicists are searching for new physics in many different directions, which naturally leads to experiments based on novel concepts. To validate them, we must make the most of the equipment that’s already available, and that is what MADMAX and CERN are doing with the Morpurgo magnet.”

CERN's endeavours to benefit science around the world have long been visible whether through collaborations, prototyping, donating equipment and more, and this is set to continue. Although we don’t need another hero, we wish the MADMAX researchers well in their quest for axions.

Note:

CERN, the European Organization for Nuclear Research, is one of the world’s largest and most respected centres for scientific research. Its business is fundamental physics, finding out what the Universe is made of and how it works. At CERN, the world’s largest and most complex scientific instruments are used to study the basic constituents of matter — the fundamental particles. By studying what happens when these particles collide, physicists learn about the laws of Nature.

The instruments used at CERN are particle accelerators and detectors. Accelerators boost beams of particles to high energies before they are made to collide with each other or with stationary targets. Detectors observe and record the results of these collisions.

Founded in 1954, the CERN Laboratory sits astride the Franco–Swiss border near Geneva. It was one of Europe’s first joint ventures and now has 23 Member States.

Related links:

MADMAX collaboration: https://madmax.mpp.mpg.de/

Charge-parity (CP) symmetry violation: https://home.cern/science/physics/matter-antimatter-asymmetry-problem

CAST experiment: https://home.cern/science/experiments/cast

For more information about European Organization for Nuclear Research (CERN), Visit: https://home.cern/

Image (mentioned), Text, Credits: CERN/By Thomas Hortala.

Best regards, Orbiter.ch

Mars Is Getting a New Robotic Meteorologist

 

NASA - Mars 2020 Perseverance Rover logo.

Nov. 14, 2020

Sensors on NASA's Perseverance will help prepare for future human exploration by taking weather measurements and studying dust particles.

Image above: NASA's Perseverance Mars rover has two wind sensors just below its mast, or "head." They're part of MEDA, a weather science package that will provide vital data on the Martian surface, especially dust in the atmosphere. Image Credits: NASA/JPL-Caltech.

Mars is about to get a new stream of weather reports, once NASA's Perseverance rover touches down on Feb. 18, 2021. As it scours Jezero Crater for signs of ancient microbial life, Perseverance will collect the first planetary samples for return to Earth by a future mission. But the rover will also provide key atmospheric data that will help enable future astronauts to the Red Planet to survive in a world with no breathable oxygen, freezing temperatures, planet wide dust storms, and intense radiation from the Sun.

The instrument behind the weather data is called MEDA - short for the Mars Environmental Dynamics Analyzer. Part of its goal is to gather the basics: temperature, wind speed and direction, pressure, and relative humidity. Models of the temperature at Perseverance's landing site range from an average of minus 126 degrees Fahrenheit (minus 88 degrees Celsius) at night to about minus 9 degrees Fahrenheit (minus 23 degrees Celsius) in the afternoon.

Together with weather instruments aboard NASA's Curiosity rover and InSight lander, the three spacecraft will create "the first meteorological network on another planet," said Jose Antonio Rodriguez-Manfredi, MEDA principal investigator with the Centro de Astrobiología (CAB) at the Instituto Nacional de Tecnica Aeroespacial in Madrid, Spain.

But a key difference between MEDA and its predecessors is that it will also measure the amount, shape, and size of dust particles in the Martian atmosphere. Dust is a big consideration for any surface mission on Mars. It gets all over everything, including spacecraft and any solar panels they may have. It also drives chemical processes both on the surface and in the atmosphere, and it affects temperature and weather. The Perseverance team wants to learn more about these interactions; doing so will help the team planning operations for the Ingenuity Mars helicopter as well.

"Understanding Martian dust is very important for this mission," said Rodriguez-Manfredi. "Those fine grains of dust lift off the surface and cover the entire planet. We don't know how Martian winds and changes in temperature are able to cause those global dust storms, but this will be important information for future missions."

While those storms don't blow with the force you see in movies (Mars' atmosphere is too thin for that), they can create a thick blanket of dust. A global dust storm in the summer of 2018 ended the mission of NASA's most seasoned rover, the solar-powered Opportunity, after almost 15 years of operations.

Animation above: One of two wind sensors springs out of the mast on NASA's Perseverance Mars rover. These sensors are part of Perseverance's weather instrumentation, called MEDA. Image Credits: NASA/JPL-Caltech.

Even on placid days, dust on Mars is pervasive - and invasive.

MEDA will be able to measure the details of the diurnal dust cycle: "We know that the atmosphere essentially stirs up the dust at noon. Then at nighttime, when the temperatures go down, the atmosphere stabilizes and there's less dust," said Manuel de la Torre Juarez, MEDA's deputy principal investigator with NASA's Jet Propulsion Laboratory in Southern California. "We want to know more because as our missions to Mars get bigger, dust considerations could also become more relevant."

Apollo astronauts found lunar dust to be a general nuisance, getting into helmet rings, sticking to spacesuits, and affecting the spacesuits' cooling systems. The Apollo missions on the Moon only lasted a few days. Human missions to Mars likely will be much longer, so new data about daily dust cycles will benefit mission planners as well as spacecraft and spacesuit designers.

Cold and Cloudy With a Lot of Radiation

Airborne dust even factors into the amount of solar radiation bombarding the Martian surface. On Earth, our atmosphere, along with our planet's magnetic field, shields us from radiation. But there is no global magnetic field at Mars, and its atmosphere is just 1% the density of Earth's. So measuring dust and radiation go hand in hand, especially for spacesuit design.

"Radiation is probably the most extreme condition for the astronauts," said Rodriguez-Manfredi. "The suits protecting the astronauts from this radiation will be crucial."

Image above: SkyCam is a sky-facing camera aboard NASA's Perseverance Mars rover. As part of MEDA, the rover's set of weather instruments, SkyCam will take images and video of clouds passing in the Martian sky. Image Credits: NASA/JPL-Caltech.

To that end, MEDA's SkyCam will photograph and make videos of the sky and clouds while monitoring sky brightness in a variety of wavelengths to help us better understand the radiation environment on Mars.

"We'll have our own camera to monitor those clouds and the opacity - and the amount of dust or other aerosols in the atmosphere that may be changing the intensity of the solar radiation," said Rodriguez-Manfredi. "We'll be able to see how the amount of dust in the atmosphere changes on an hourly basis."

The information will also benefit Perseverance's search for past life. As on Earth, if life ever existed on Mars, it was likely based on organic molecules. Solar radiation can alter traces of that past life in rocks, and data from MEDA will help scientists understand those changes.

Clearing the Air

MEDA's data will help another instrument on Perseverance: the Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE). MOXIE will demonstrate a technology that future explorers might use to produce oxygen that can be used for rocket propellant and for breathing. For devices like MOXIE to succeed, mission planners will need more information on what they're up against. "Are they getting a clean atmosphere?" said de la Torre Juarez. "Are they getting a dusty atmosphere? Is this dust going to end up essentially filling up the air filters or not? They may identify times of the day when it is better to run MOXIE, versus times when it is better not to run it."

To take its measurements, MEDA will wake itself up each hour, day and night, whether Perseverance is roving or napping. That will create a nearly constant stream of information to help fill the gaps in our knowledge about the Martian atmosphere.

More About the Mission

A key science objective for Perseverance's mission on Mars is astrobiology, including the search for signs of ancient microbial life. The rover will characterize the planet's geology and past climate, pave the way for human exploration of the Red Planet, and be the first mission to collect and cache Martian rock and regolith (broken rock and dust).

Subsequent missions, currently under consideration by NASA in cooperation with the European Space Agency, would send spacecraft to Mars to collect these cached samples from the surface and return them to Earth for in-depth analysis.

The Mars 2020 mission is part of a larger program that includes missions to the Moon as a way to prepare for human exploration of the Red Planet. Charged with returning astronauts to the Moon by 2024, NASA will establish a sustained human presence on and around the Moon by 2028 through NASA's Artemis lunar exploration plans: https://www.nasa.gov/specials/artemis/

JPL, which is managed for NASA by Caltech in Pasadena, California, built and manages operations of the Perseverance rover.

Related article:

NASA's Perseverance Rover Is Midway to Mars
https://orbiterchspacenews.blogspot.com/2020/10/nasas-perseverance-rover-is-midway-to.html

For more about Perseverance:

https://mars.nasa.gov/mars2020/

https://nasa.gov/perseverance

Images (mentioned), Animation (mentioned), Text, Credits: NASA/Alana Johnson/Grey Hautaluoma/JPL/Andrew Good.

Greetings, Orbiter.ch

ULA - Atlas V launches NROL-101

ULA - Atlas V / NROL-101 Mission poster.

Nov. 13, 2020

 Atlas V launches NROL-101

A United Launch Alliance (ULA) Atlas V 531 rocket launched the NROL-101 mission for the National Reconnaissance Office (NRO), from Space Launch Complex 41 at Cape Canaveral Air Force Station, Florida, on 13 November 2020, at 22:32 UTC (17:32 EST).

Atlas V launches NROL-101

The mission was the 86th for an Atlas V launch vehicle and the 4th in the 531 configuration. This was the first Atlas V rocket powered by Northrop Grumman’s GEM 63 boosters.

Atlas V

ULA’s Atlas V rocket is a workhorse for the U.S. military, intelligence community and scientific researchers. Developed as a modular vehicle, each Atlas V is tailored to the needs of its passenger by adding as many as five side-mounted solid rocket boosters for increased lift performance and a variety of available payload fairings in various diameters and lengths to protect satellites during atmospheric ascent. The high-energy Centaur upper stage, which has been used to send spacecraft to every planet in our solar system, is incorporated into Atlas V to deliver the payloads to their intended destinations.

United Launch Alliance (ULA): https://www.ulalaunch.com/

National Reconnaissance Office (NRO): https://www.nro.gov/

Images, Video, Text, Credits: Credits: Illustration, photos and video footage courtesy of United Launch Alliance/SciNews/Orbiter.ch Aerospace/Roland Berga.

Greetings, Orbiter.ch

CASC - Long March-3B launches Tiantong-1 02

 

CASC - China Aerospace Science and Technology Corporation logo.

Nov. 13, 2020

Long March-3B launches Tiantong-1 02

A Long March-3B launch vehicle launched the Tiantong-1-02 satellite from the Xichang Satellite Launch Center, Sichuan Province, southwest China, on 12 November 2020, at 15:59 UTC (12 November, at 23:59 local time).

Long March-3B launches Tiantong-1 02

Tiantong-1-02 (天通一号02) is the second mobile communication satellite designed by the China Academy of Space Technology (CAST) and operated by China Satcom (China Satellite Communications Co. Ltd).

Tiantong-1-02 (天通一号02)

Related links:

China Academy of Space Technology (CAST): https://www.cast.cn/

China Satcom (China Satellite Communications Co. Ltd): http://english.csat.spacechina.com/

For more information about China Aerospace Science and Technology Corporation (CASC): http://english.spacechina.com/n16421/index.html
 
Images, Video, Text, Credits: CASC/China Central Television (CCTV)/SciNews/Günter's Space Page/Orbiter.ch Aerospace/Roland Berga.

Greetings, Orbiter.ch

Launch Readiness Review Complete, Prelaunch News Conference at 6 p.m. EST

 

NASA & SpaceX - Dragon Crew-1 Mission patch.

Nov. 13, 2020

Teams completed the final major review today for NASA’s SpaceX Crew-1 mission that will launch from the agency’s Kennedy Space Center in Florida to the International Space Station. At the conclusion of the review, NASA and SpaceX agreed to target launch for 7:27 p.m. EST Sunday, Nov. 15, due to onshore winds and first stage booster recovery readiness. NASA TV coverage will begin at 3:15 p.m. The Crew Dragon is scheduled to dock to the space station at about 11 p.m. Monday, Nov. 16.

Image above: The launch of NASA’s SpaceX Crew-1 mission is now targeted for Sunday, Nov. 15, at 7:27 p.m. EST. Photo credit: NASA/Aubrey Gemignani.

Coming up at 6 p.m. is a prelaunch news conference, live on NASA Television and the agency’s website. Participants are:

    Steve Stich, manager, Commercial Crew Program, Kennedy
    Joel Montalbano, manager, International Space Station, Johnson Space Center
    Kirt Costello, chief scientist, International Space Station Program, Johnson
    Norm Knight, deputy manager, Flight Operations Directorate, Johnson
    Benji Reed, senior director, Human Spaceflight Programs, SpaceX
    Arlena Moses, launch weather officer, U.S. Air Force 45th Weather Squadron

NASA astronauts Michael Hopkins, Victor Glover, and Shannon Walker, and astronaut Soichi Noguchi of the Japan Aerospace Exploration Agency (JAXA) will head to the International Space Station for a six-month science mission in the Crew Dragon spacecraft, which will launch on the SpaceX Falcon 9 rocket from Launch Complex 39A. Crew-1 is the first crew rotation flight of a U.S. commercial spacecraft with astronauts to the space station following the spacecraft system’s official human rating certification.

Related article:

NASA and SpaceX Complete Certification of First Human-Rated Commercial Space System
https://orbiterchspacenews.blogspot.com/2020/11/nasa-and-spacex-complete-certification.html

Related links:

NASA Television: https://www.nasa.gov/nasalive

Commercial Crew: https://www.nasa.gov/exploration/commercial/crew/index.html

SpaceX: https://www.spacex.com/

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

Image (mentioned), Text, Credits: NASA/James Cawley.

Best regards, Orbiter.ch

The Personal Preference Kit: What Astronauts Take With Them To Space

 

NASA - ARTEMIS Program logo.

Nov. 12, 2020

NASA recently asked the public what items they would take with them on a trip to the Moon, inviting more than 11,000 responses on social media, submitted using the hashtag #NASAMoonKit. Moon kit responders submitted pictures and videos that either depicted a metaphoric view of what they would bring, or took a more technically accurate approach of following “Expert Mode” that followed actual Personal Preference Kit (PPK) dimensions: 5” by 8” by 2” (12.7 cm x 20.32 cm x 5.08 cm), which is about the size of a lunch box.

Image above: Each astronaut is allowed a 5” by 8” by 2” (12.7 cm x 20.32 cm x 5.08 cm) volume when they travel to the International Space Station. Try to make your #NASAMoonKit fit into this tight space and show us how you did it with a picture or video!. Image Credit: NASA.

“The Moon Kit idea came up as we were checking off milestone after milestone, getting closer to the launch of Artemis I,” explained Kathy Lueders, NASA’s Associate Administrator of the Human Exploration and Operations Mission Directorate. “As excitement mounts for the first Artemis mission, we wanted a fun way to get people thinking about humanity’s return to the Moon.”

With #NASAMoonKit, we are learning about what the general public would bring on a journey to the Moon, but what do real astronauts take with them on missions into space? Information about the items that astronauts take with them is usually kept very private, but typical PPK items include family photos, organizational flags, t-shirts, ball-caps, books, religious texts, and personal mementos.  

The use of the PPK dates back as far as the Gemini program, but the PPK looked a little different then. Gemini astronauts were allowed to carry personal objects in a grey nylon bag, about 6” x 7” (15.24 cm x 17.78 cm), which could be closed with a drawstring. Mercury and Gemini astronaut Wally Schirra shared the content of his Gemini 6A PPK, which included Navy wings, a Florida hunting license, 20 gold medals, 5 silver medals, various flags, and 15 GTA-6 patches.

The PPK got a bit of an upgrade for the Apollo missions. The standard Apollo PPK bag measured 8” x 4” x 2” (20.32 cm x 10.16 cm x 5.08 cm). Sometimes the items taken aboard were used later to be given to people as awards — for instance, a sphere of aluminum that astronaut Frank Borman took with him on the Apollo 8 mission was used to strike 200,000 medallions for those who contributed to the Apollo program.

Image above: A close-up view of a replica of the plaque which the Apollo 12 astronauts left on the Moon in commemoration of their flight. Image Credit: NASA.

Among the items carried by Michael Collins during the historic Apollo 11 flight to the lunar surface were three flags; the U.S. Flag, the flag of the District of Columbia, and the flag of the U.S. Air Force. In response to the #NASAMoonKit challenge on Twitter, Michael Collins responded: "I'd still want coffee and would add a good book."

During the Apollo 12 mission, the astronauts did not just take the one mission plaque to leave on the Moon — they took four thin aluminum light-weight copies with them in their PPKs. The copies they returned to Earth went to the three crew members, Charles “Pete” Conrad Jr., Richard Gordon, and Alan Bean. Conrad’s next-door neighbor who made the copies for them, Jack Kinzler, received the fourth copy.

During the Space Shuttle era, the contents of a PPK were limited to 20 separate items which had to fit in a 5" × 8" × 2" (12.7 cm x 20.32 cm x 5.08 cm) bag. The bag also had a weight limit of 3.3 lbs (1.5 kg). Shuttle astronauts were also allowed an Official Flight Kit (OFK), in which they were allowed to bring mementos for organizations that were important to the crewmember. Astronaut Rhea Seddon, veteran of three space shuttle flights, took with her a pennant for her university, a sorority pin, and a ball cap for an athletic team. She also took a long roll of calculator tape with signatures from every student in her hometown, so they could all say their signature flew in space.

Image above: Expedition 43 Commander and NASA astronaut Terry Virts is seen here in the International Space Station's Cupola module, a 360 degree Earth and space viewing platform. The module also contains a robotic workstation for controlling the station's main robotic arm, Canadarm2, which is used for a variety of operations including the remote grappling of visiting cargo vehicles. Image Credit: NASA.

Today, on missions to the International Space Station, both the Soyuz spacecraft and the SpaceX Crew Dragon spacecraft allocates 3.3 lbs (1.5 kg) for personal preference items. Many astronauts bring musical instruments to the space station and leave them there for future use. For his 39th birthday in 2017, ESA astronaut Thomas G. Pesquet’s Expedition 50 crewmates surprised him with an alto saxophone that they had conspired to be delivered to ISS and had somehow managed to keep hidden from him. Lots of astronauts also bring camera gear, as photography is a favorite pastime when orbiting above fantastic views of Earth.

As the Artemis program continues to take steps to land the first woman and the next man on the Moon, astronaut will soon begin preparing what will go into their actual #NASAMoonKits. What would you bring?

Related links:

#NASAMoonKit: http://www.nasa.gov/nasamoonkit

Artemis: https://www.nasa.gov/artemisprogram

Images (mentioned), Text, Credits: NASA/Thalia Patrinos.

Greetings, Orbiter.ch

Potential Plumes on Europa Could Come From Water in the Crust

 

NASA - Europa Clipper Mission patch.

Nov. 13, 2020

Scientists have theorized on the origin of the water plumes possibly erupting from Jupiter's moon Europa. Recent research adds a new potential source to the mix.

Image above: This illustration of Jupiter's icy moon Europa depicts a cryovolcanic eruption in which brine from within the icy shell could blast into space. A new model proposing this process may also shed light on plumes on other icy bodies. Image Credits: Justice Wainwright.

Plumes of water vapor that may be venting into space from Jupiter's moon Europa could come from within the icy crust itself, according to new research. A model outlines a process for brine, or salt-enriched water, moving around within the moon's shell and eventually forming pockets of water – even more concentrated with salt – that could erupt.

Europa scientists have considered the possible plumes on Europa a promising way to investigate the habitability of Jupiter's icy moon, especially since they offer the opportunity to be directly sampled by spacecraft flying through them. The insights into the activity and composition of the ice shell covering Europa's global, interior ocean can help determine if the ocean contains the ingredients needed to support life.

This new work that offers an additional scenario for some plumes proposes that they may originate from pockets of water embedded in the icy shell rather than water forced upward from the ocean below. The source of the plumes is important: Water originating from the icy crust is considered less hospitable to life than the global interior ocean because it likely lacks the energy that is a necessary ingredient for life. In Europa's ocean, that energy could come from hydrothermal vents on the sea floor.

"Understanding where these water plumes are coming from is very important for knowing whether future Europa explorers could have a chance to actually detect life from space without probing Europa's ocean," said lead author Gregor Steinbrügge, a postdoctoral researcher at Stanford's School of Earth, Energy & Environmental Sciences.

Using images collected by NASA's Galileo spacecraft, the researchers developed a model to propose how a combination of freezing and pressurization could lead to a cryovolcanic eruption, or a burst of frigid water. The results, published Nov. 10 in Geophysical Research Letters, may shed light on eruptions on other icy bodies in the solar system.

The researchers focused their analyses on Manannán, an 18-mile-wide (29-kilometer-wide) crater on Europa that resulted from an impact with another celestial object tens of millions of years ago. Reasoning that such a collision would have generated tremendous heat, they modeled how the melted ice and subsequent freezing of the water pocket within the icy shell could have pressurized it and caused the water to erupt.

"The comet or asteroid hitting the ice shell was basically a big experiment which we're using to construct hypotheses to test," said co-author Don Blankenship, senior research scientist at the University of Texas Institute for Geophysics (UTIG) and principal investigator of the radar instrument, REASON (Radar for Europa Assessment and Sounding: Ocean to Near-surface), that will fly aboard NASA’s upcoming Europa Clipper spacecraft. "Our model makes specific predictions we can test using data from the radar and other instruments on Europa Clipper."

The model indicates that as Europa's water partially froze into ice following the impact, leftover pockets of water could have been created in the moon's surface. These salty water pockets can move sideways through Europa's ice shell by melting adjacent regions of ice and consequently become even saltier in the process.

A Salty Driving Force

The model proposes that when a migrating brine pocket reached the center of Manannán Crater, it became stuck and began freezing, generating pressure that eventually resulted in a plume, estimated to have been over a mile high (1.6 kilometers). The eruption of this plume left a distinguishing mark: a spider-shaped feature on Europa's surface that was observed by Galileo imaging and incorporated into the researchers' model.

"Even though plumes generated by brine pocket migration would not provide direct insight into Europa's ocean, our findings suggest that Europa's ice shell itself is very dynamic," said co-lead author Joana Voigt, a graduate research assistant at the University of Arizona, in Tucson.

Europa Clipper. Image Credits: NASA/JPL-Caltech

The relatively small size of the plume that would form at Manannán indicates that impact craters probably can't explain the source of other, larger plumes on Europa that have been hypothesized based on data from Galileo and NASA's Hubble Space Telescope, researchers said. But the process modeled for the Manannán eruption could happen on other icy bodies – even without an impact event.

"The work is exciting, because it supports the growing body of research showing there could be multiple kinds of plumes on Europa," said Robert Pappalardo of NASA's Jet Propulsion Laboratory in Southern California and project scientist of the Europa Clipper mission. "Understanding plumes and their possible sources strongly contributes to Europa Clipper's goal to investigate Europa's habitability."

Missions such as Europa Clipper help contribute to the field of astrobiology, the interdisciplinary research on the variables and conditions of distant worlds that could harbor life as we know it. While Europa Clipper is not a life-detection mission, it will conduct detailed reconnaissance of Europa and investigate whether the icy moon, with its subsurface ocean, has the capability to support life. Understanding Europa's habitability will help scientists better understand how life developed on Earth and the potential for finding life beyond our planet.

Related article:

Europa Glows: Radiation Does a Bright Number on Jupiter's Moon
https://orbiterchspacenews.blogspot.com/2020/11/europa-glows-radiation-does-bright.html

Related links:

Europa Clipper: http://www.nasa.gov/europa

Galileo: https://www.jpl.nasa.gov/missions/galileo/

School of Earth, Energy & Environmental Sciences: https://earth.stanford.edu/

Images (mentioned), Text, Credits: NASA/Tony Greicius/Grey Hautaluoma/Alana Johnson/JPL/Gretchen McCartney/Stanford University School of Earth, Energy & Environmental Sciences/Danielle Torrent Tucker.

Best regards, Orbiter.ch

Heat and Dust Help Launch Martian Water Into Space, Scientists Find

 

NASA - MAVEN Mission patch.

Nov. 13, 2020

Scientists using an instrument aboard NASA’s Mars Atmosphere and Volatile EvolutioN, or MAVEN, spacecraft have discovered that water vapor near the surface of the Red Planet is lofted higher into the atmosphere than anyone expected was possible. There, it is easily destroyed by electrically charged gas particles — or ions — and lost to space.

Researchers said that the phenomenon they uncovered is one of several that has led Mars to lose the equivalent of a global ocean of water up to hundreds of feet (or up to hundreds of meters) deep over billions of years.  Reporting on their finding on Nov. 13 in the journal Science, researchers said that Mars continues to lose water today as vapor is transported to high altitudes after sublimating from the frozen polar caps during warmer seasons.

Global Storms on Mars Launch Dust Towers Into the Sky. Animation Credit: NASA

“We were all surprised to find water so high in the atmosphere,” said Shane W. Stone, a doctoral student in planetary science at the University of Arizona’s Lunar and Planetary Laboratory in Tucson. “The  measurements we used could have only come from MAVEN as it soars through the atmosphere of Mars, high above the planet’s surface.”

To make their discovery, Stone and his colleagues relied on data from MAVEN’s Neutral Gas and Ion Mass Spectrometer (NGIMS), which was developed at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. The mass spectrometer inhales air and separates the ions that comprise it by their mass, which is how scientists identify them.

Stone and his team tracked the abundance of water ions high over Mars for more than two Martian years. In doing so, they determined that the amount of water vapor near the top of the atmosphere at about 93 miles, or 150 kilometers, above the surface is highest during summer in the southern hemisphere. During this time, the planet is closest to the Sun, and thus warmer, and dust storms are more likely to happen.

Image above: This graph shows how the amount of water in the atmosphere of Mars varies depending on the season. During global and regional dust storms, which happen during southern spring and summer, the amount of water spikes. Image Credits: University of Arizona/Shane Stone/NASA Goddard/Dan Gallagher.

The warm summer temperatures and strong winds associated with dust storms help water vapor reach the uppermost parts of the atmosphere, where it can easily be broken into its constituent oxygen and hydrogen. The hydrogen and oxygen then escape to space. Previously, scientists thought that water vapor was trapped close to the Martian surface like it is on Earth.

“Everything that makes it up to the higher part of the atmosphere is destroyed, on Mars or on Earth,” Stone said, “because this is the part of the atmosphere that is exposed to the full force of the Sun.”

Image above: This illustration shows how water is lost on Mars normally vs. during regional or global dust storms. Image Credits: NASA/Goddard/CI Lab/Adriana Manrique Gutierrez/Krysrofer Kim.

The researchers measured 20 times more water than usual over two days in June 2018, when a severe global dust storm enveloped Mars (the one that put NASA’s Opportunity rover out of commission). Stone and his colleagues estimated Mars lost as much water in 45 days during this storm as it typically does throughout an entire Martian year, which lasts two Earth years.

“We have shown that dust storms interrupt the water cycle on Mars and push water molecules higher in the atmosphere, where chemical reactions can release their hydrogen atoms, which are then lost to space,” said Paul Mahaffy, director of the Solar System Exploration Division at NASA Goddard and principal investigator of NGIMS.

Other scientists have also found that Martian dust storms can lift water vapor far above the surface. But nobody realized until now that the water would make it all the way to the top of the atmosphere. There are abundant ions in this region of the atmosphere that can break apart water molecules 10 times faster than they’re destroyed at lower levels.

Mars Atmosphere and Volatile Evolution (MAVEN). Image Credit: NASA

“What’s unique about this discovery is that it provides us with a new pathway that we didn’t think existed for water to escape the Martian environment,” said Mehdi Benna, a Goddard planetary scientist and co-investigator of MAVEN’s NGIMS instrument. “It will fundamentally change our estimates of how fast water is escaping today and how fast it escaped in the past.”

This research was funded by the MAVEN mission. MAVEN's principal investigator is based at the University of Colorado Boulder's Laboratory for Atmospheric and Space Physics, and NASA Goddard manages the MAVEN project.

Related links:

Solar System Exploration Division: https://science.gsfc.nasa.gov/solarsystem/

Science: https://science.sciencemag.org/content/370/6518/824

Lunar and Planetary Laboratory: https://www.lpl.arizona.edu/

NASA’s Goddard Space Flight Center (GSFC): https://www.nasa.gov/centers/goddard/home/index.html

MAVEN (Mars Atmosphere and Volatile Evolution): https://www.nasa.gov/mission_pages/maven/main/index.html

Animation (mentioned), Images (mentioned), Text, Credits: NASA/Svetlana Shekhtman/GSFC/By Lonnie Shekhtman.

Greetings, Orbiter.ch

Recreating Big Bang matter on Earth

 

CERN - European Organization for Nuclear Research logo.

Nov. 13, 2020

Our fifth story in the LHC Physics at Ten series looks at how the LHC has recreated and greatly advanced our knowledge of the state of matter that is believed to have existed shortly

Large Hadron Collider (LHC). Animation Credit: CERN

The Large Hadron Collider (LHC) at CERN usually collides protons together. It is these proton–proton collisions that led to the discovery of the Higgs boson in 2012. But the world’s biggest accelerator was also designed to smash together heavy ions, primarily the nuclei of lead atoms, and it does so every year for about one month. And for at least two good reasons. First, heavy-ion collisions at the LHC recreate in laboratory conditions the plasma of quarks and gluons that is thought to have existed shortly after the Big Bang. Second, the collisions can be used to test and study, at the highest manmade temperatures and densities, fundamental predictions of quantum chromodynamics, the theory of the strong force that binds quarks and gluons together into protons and neutrons and ultimately all atomic nuclei.

The LHC wasn’t the first machine to recreate Big Bang matter: back in 2000, experiments at the Super Proton Synchrotron at CERN found compelling evidence of the quark–gluon plasma. About five years later, experiments at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory in the US started an era of detailed investigation of the quark–gluon plasma. However, in the 10 years since it achieved collisions at higher energies than its predecessors, the LHC has taken studies of the quark–gluon plasma to incredible new heights. By producing a hotter, denser and longer-lived quark–gluon plasma as well as a larger number and assortment of particles with which to probe its properties and effects, the LHC has allowed physicists to study the quark–gluon plasma with an unprecedented level of detail. What’s more, the machine has delivered some surprising results along the way, stimulating new theoretical studies of this state of matter.

“In the ultimate textbook about the theory of the strong interaction, the chapter on the quark–gluon plasma will be filled with figures of LHC data,” says ALICE experiment spokesperson Luciano Musa.

“These figures excel in data precision and kinematic reach, and they are the first to inform us about how quark–gluon plasma-like properties emerge gradually as one transitions from proton–proton to heavy-ion collisions.”

Image above: Illustration of the history of the universe. About one microsecond (μs) from the Big Bang, protons formed from the quark–gluon plasma. (Image: BICEP2 Collaboration/CERN/NASA).

Heavy collision course

When heavy nuclei smash into one another in the LHC, the hundreds of protons and neutrons that make up the nuclei release a large fraction of their energy into a tiny volume, creating a fireball of quarks and gluons. These tiny bits of quark–gluon plasma only exist for fleeting moments, with the individual quarks and gluons, collectively known as partons, quickly forming composite particles and antiparticles that fly out in all directions. By studying the zoo of particles produced in the collisions – before, during and after the plasma is created – researchers can study the plasma from the moment it is produced to the moment it cools down and gives way to a state in which composite particles called hadrons can form. However, the plasma cannot be observed directly. Its presence and properties are deduced from the experimental signatures it leaves on the particles that are produced in the collisions and their comparison with theoretical models.

Such studies can be divided into two distinct categories. The first kind of study investigates the thousands of particles that emerge from a heavy-ion collision collectively, providing information about the global, macroscopic properties of the quark-gluon plasma. The second kind focuses on various types of particle with large mass or momentum, which are produced more rarely and offer a window into the inner, microscopic workings of the medium.

At the LHC, these studies are conducted by the collaborations behind all four main LHC experiments: ALICE, ATLAS, CMS and LHCb. Although ALICE was initially specifically designed to investigate the quark–gluon plasma, the other three experiments have also since joined this investigation.

Global properties

The LHC has delivered data that has enabled researchers to derive with higher precision than previously achieved several global properties of the medium.

“The LHC can “hear” much more precisely the quark–gluon plasma,” says CERN theorist and quark–gluon plasma specialist Urs Wiedemann.

“If we listen to two different musical instruments with closed eyes, we can distinguish between the instruments even when they are playing the same note. The reason is that a note comes with a set of overtones that give the instrument a unique distinct sound. This is but one example of how simple but powerful overtones are in identifying material properties. Heavy-ion physicists have learnt how to make use of “overtones” in their study of the quark–gluon plasma. The initial stage of a heavy-ion collision produces ripples in the plasma that travel through the medium and excite overtones. Such overtones can be measured by analysing the collective flow of particles that fly out of the plasma and reach the detectors. While previous measurements had revealed only first indications of these overtones, the LHC experiments have mapped them out in detail. Combined with other strides in precision, these data have been used by theorists to characterise the plasma’s properties, such as its temperature, energy density and frictional resistance, which is smaller than that of any other known fluid,” explains Wiedemann.

These findings have then been supported in multiple ways. For instance, the ALICE collaboration estimated the temperature of the plasma by studying photons that are emitted by the hot fireball. The estimated temperature, about 300 MeV (1 MeV is about 10¹⁰ kelvin), is above the predicted temperature necessary for the plasma to be created (about 160 MeV), and is about 40% higher than the one obtained by the RHIC collider.

Another example is the estimation of the energy density of the plasma in the initial stage of the collisions. ALICE and CMS obtained a value in the range 12–14 GeV per cubic femtometre (1 femtometre is 10^-15 metres), about 2–3 times higher than that determined by RHIC, and again above the predicted energy density needed for the plasma to form (about 1 GeV/fm3).

Image above: Particle trajectories and energy deposition in the ALICE detector during the last lead–lead collisions of the second LHC run. (Image: CERN).

Inner workings

The LHC has supplied not just more particles but also more varied types of particle with which to probe the quark–gluon plasma.

“The LHC has given us access to a very broad palette of probes,” says ALICE physics coordinator Andrea Dainese.

“Together with state-of-the-art particle detectors that cover more area around the collision points as well as sophisticated methods of identifying and tracking particles, this broad palette has offered unprecedented insight into the inner workings and effects of the quark–gluon plasma.”

To give a few examples, soon after the LHC started, ATLAS and CMS made the first direct observation of the phenomenon of jet quenching, in which jets of particles formed in the collisions lose energy as they cross the quark–gluon plasma medium. The collaborations found a striking imbalance in the energies of pairs of jets, with one jet almost completely absorbed by the medium.

Another example concerns heavy quarks. Such particles are excellent probes of the quark–gluon plasma because they are produced in the initial stages of a heavy-ion collision and therefore experience the entire evolution of the plasma. The ALICE collaboration has more recently shown that heavy quarks “feel” the shape and size of the quark–gluon plasma, indicating that even the heaviest quarks move with the medium, which is mostly made of light quarks and gluons.

The LHC experiments, in particular ALICE and CMS, have also significantly improved our understanding of the hierarchical “melting” in the plasma of bound states of a heavy quark and its antiquark, called quarkonia. The more weakly bound the states are, the more easily they will melt, and as a result the less abundant they will be. CMS was the first to observe this so-called hierarchical suppression for bottomonium states, which consist of a bottom quark and its antiquark. And ALICE revealed that, while the most common form of charmonium states, which are composed of a charm quark and its antiquark, is highly suppressed due to the effect of the plasma, it is also regenerated by the recombination of charm quarks and antiquarks. This recombination phenomenon, observed for the first time at the LHC, provides an important testing ground for theoretical models and phenomenology, which forms a link between the theoretical models and experimental data.

Surprises in smaller systems

The LHC data have also revealed unexpected results. For example, the ALICE collaboration showed that the enhanced production of strange hadrons (particles containing at least one strange quark), which is traditionally viewed as a signature of the quark-gluon plasma, arises gradually in proton–proton and proton–lead collisions as the number of particles produced in the collisions, or “multiplicity”, increases.

Another case in point is the gradual onset of a flow-like feature with the shape of a ridge with increasing multiplicity, which was first observed by CMS in proton–proton and proton–lead collisions. This result was further supported by ALICE and ATLAS observations of the emergence of double-ridge features in proton–lead collisions.

Image above: As the number of particles produced in proton–proton collisions increases (blue lines), the more particles containing at least one strange quark are measured (orange to red squares in the graph). (Image: CERN).

“The discovery of heavy-ion-like behaviour in proton–proton and proton–nucleus collisions at the LHC is a game-changer,” says Wiedemann.

“The LHC data have killed the long-held view that proton–proton collisions produce free-streaming sets of particles while heavy-ion collisions produce a fully developed quark–gluon plasma. And they tell us that in the small proton–proton collision systems there are more physical mechanisms at work than traditionally thought. The new challenge is to understand, within the theory of the strong force, how quark–gluon plasma-like properties emerge gradually with the size of the collision system.”

These are just examples of how 10 years of the LHC have greatly advanced physicists’ knowledge of the quark–gluon plasma and thus of the early universe. And with data from the machine’s second run still being analysed and more data to come from the next run and the High-Luminosity LHC, the LHC’s successor, an even more detailed understanding of this unique state of matter is bound to emerge, perhaps with new surprises in the mix.

“The coming decade at the LHC offers many opportunities for further exploration of the quark–gluon plasma,” says Musa. “The expected tenfold increase in the number of lead–lead collisions should both increase the precision of measurements of known probes of the medium and give us access to new probes. In addition, we plan to explore collisions between lighter nuclei, which could cast further light on the nature of the medium.”

Note:

CERN, the European Organization for Nuclear Research, is one of the world’s largest and most respected centres for scientific research. Its business is fundamental physics, finding out what the Universe is made of and how it works. At CERN, the world’s largest and most complex scientific instruments are used to study the basic constituents of matter — the fundamental particles. By studying what happens when these particles collide, physicists learn about the laws of Nature.

The instruments used at CERN are particle accelerators and detectors. Accelerators boost beams of particles to high energies before they are made to collide with each other or with stationary targets. Detectors observe and record the results of these collisions.

Founded in 1954, the CERN Laboratory sits astride the Franco–Swiss border near Geneva. It was one of Europe’s first joint ventures and now has 23 Member States.

Further reading:

LHC at 10: the physics legacy:
https://cerncourier.com/a/lhc-at-10-the-physics-legacy/

An overview of experimental results from ultra-relativistic heavy-ion
collisions at the CERN LHC: bulk properties and dynamical evolution:
https://arxiv.org/abs/1702.07233/

An overview of experimental results from ultra-relativistic heavy-ion collisions at the CERN LHC: hard probes:
https://arxiv.org/abs/1702.07231

Related links:

First direct observation: https://home.cern/news/press-release/cern/lhc-experiments-bring-new-insight-primordial-universe

High-Luminosity LHC: https://home.cern/science/accelerators/high-luminosity-lhc

Large Hadron Collider (LHC): https://home.cern/science/accelerators/large-hadron-collider

ATLAS: https://home.cern/science/experiments/atlas

ALICE:  https://home.cern/science/experiments/alice

CMS:  https://home.cern/science/experiments/cms

LHCb: https://home.cern/science/experiments/lhcb

Standard Model: https://home.cern/science/physics/standard-model

For more information about European Organization for Nuclear Research (CERN), Visit: https://home.cern/

Animation (mentioned), Images (mentioned), Text, Credits: CERN/By Ana Lopes.

Best regards, Orbiter.ch