- TRAPPIST-1 exoplanet seems to have no atmosphere — the truth may hide in its star, James Webb Space Telescope reveals Space.com
- James Webb analyzes atmosphere of first TRAPPIST planet New Atlas
- JWST just scanned the skies of potentially habitable exoplanet TRAPPIST-1 b Popular Science
- ‘Ghost Signals’ from Trappist-1 Exoplanetary System Revealed by James Webb Space Telescope The Debrief
- Stellar Contamination and Ghostly Atmospheres: Webb Reveals New Insights Into TRAPPIST-1 Exoplanet SciTechDaily
- View Full Coverage on Google News
Tag Archives: atmosphere
NASA Earth Radiation Budget Satellite To Reenter Atmosphere Today
NASA’s Earth Radiation Budget Satellite is expected to burn up in the atmosphere. Here we see the ATV Jules Verne spacecraft on destructive reentry in 2008 taken from the DC-8 aircraft which observed the reentry over the Pacific Ocean. Credit: ESA
In early January
NASA expects most of the satellite to burn up as it travels through the atmosphere, but some components are expected to survive the reentry. The risk of harm coming to anyone on Earth is very low – approximately 1 in 9,400.
NASA’s Earth Radiation Budget Satellite (ERBS) was designed to examine how energy from the Sun is absorbed and re-emitted by the Earth. By understanding this process, researchers can learn more about patterns in Earth’s weather. ERBS was launched on October 5, 1984, on the Space Shuttle Challenger and retired on October 14, 2005, making it one of the longest-running spacecraft missions. Although the spacecraft was only expected to operate for two years, it actually provided scientists with data on the Earth’s ozone layer for over 20 years. Credit: NASA
Launched from the Space Shuttle Challenger on October 5, 1984, the ERBS spacecraft was part of NASA’s three-satellite Earth Radiation Budget Experiment (ERBE) mission. It carried three instruments, two to measure the Earth’s radiative energy budget, and one to measure stratospheric constituents, including ozone.
The energy budget, the balance between the amount of energy from the Sun that Earth absorbs or radiates, is an important indicator of climate health, and understanding it can also help reveal weather patterns. Ozone concentrations in the stratosphere play an important role in protecting life on Earth from damaging ultraviolet radiation.
ERBS far exceeded its expected two-year service life, operating until its retirement in 2005. Its observations helped researchers measure the effects of human activities on Earth’s radiation balance. NASA has continued to build on the success of the ERBE mission with projects including the current Clouds and the Earth’s Radiant Energy System (CERES) suite of satellite instruments.
The Stratospheric Aerosol and Gas Experiment II (SAGE II) on the ERBS made stratospheric measurements. SAGE II collected important data that confirmed the ozone layer was declining on a global scale. That data helped shape the international Montreal Protocol Agreement, resulting in a dramatic decrease around the globe in the use of ozone-destroying chlorofluorocarbons. Today, SAGE III on the International Space Station collects data on the health of the ozone layer.
Mars’ ancient atmosphere may not have had much oxygen after all
There may have been no oxygen in the atmosphere of ancient Mars after all, a new study has found — but don’t despair, there still could have been living creatures crawling on the planet’s surface.
When NASA’s Curiosity rover found manganese oxide in Martian rocks in 2016, many planetary scientists rejoiced, believing that the mineral’s presence was a significant hint of past concentrations of oxygen in the planet’s atmosphere. The odds of past existence of life on Mars suddenly seemed higher, too, as oxygen is one of the key enablers of life on Earth.
A new study based on laboratory experiments, however, has now concluded that not only were high concentrations of oxygen not necessary for the formation of the minerals, but that the expected composition of ancient Mars’ atmosphere would have prevented oxygen-reliant reactions in the first place. Instead, the scientists said, copious amounts of manganese oxide could have formed on Mars simply in the presence of halogen elements, such as chlorine and bromine, which are found on the Red Planet in greater quantities than on Earth.
Related: Curiosity rover: 15 awe-inspiring photos of Mars (gallery)
“Oxidation does not necessitate the involvement of oxygen by definition,” Kaushik Mitra, now a planetary geochemist at Stony Brook University in New York who led this study as part of his graduate research work at Washington University in St. Louis, said in a statement (opens in new tab).
Oxidation is a chemical reaction in which a molecule or atom loses electrons. The reaction doesn’t necessarily involve oxygen, but in many cases leads to the formation of oxides, such as manganese oxide found on Mars.
“Earlier, we proposed viable oxidants on Mars, other than oxygen or via UV [ultraviolet] photooxidation, that help explain why the Red Planet is red,” he said. “In the case of manganese, we just did not have a viable alternative to oxygen that could explain manganese oxides until now.”
Kaushik and his collaborators were inspired by observations of reactions occuring during chlorination of drinking water, which involves adding molecules containing chlorine into water to kill microorganisms through oxidation. The researchers decided to test whether oxidation could be occurring in the halogen-rich environment on Mars. In a laboratory, they created water samples with a composition similar to what might have been found on ancient Mars. When they submerged fragments of manganese minerals in the water, the scientists discovered that the manganese quickly dissolved, forming manganese oxide thousands to millions of times faster than in the presence of oxygen, the researchers said in the statement.
The key to this stunning rate of oxidation, the scientists determined, was that the water contained chlorate and bromate, forms of the halogens chlorine and bromine that are common on Mars. Bromate was particularly efficient in turning manganese into manganese oxides, enabling the reaction to proceed at a speedy pace. That held true even when the water samples had high concentrations of carbon dioxide, which prohibited the formation of manganese oxides in the presence of only oxygen.
This finding is key to disproving the theory about past abundance of oxygen in the atmosphere of Mars that emerged after Curiosity’s discovery. Scientists also believe that the atmosphere of ancient Mars was rich in carbon dioxide, so because carbon dioxide blocked the reactions with oxygen, the idea that the formation of manganese oxides required high concentrations of atmospheric oxygen appeared to no longer hold water.
“The link between manganese oxides and oxygen suffers from an array of fundamental geochemical problems,” Jeffrey Catalano, a geochemist at Washington University, St, Louis, and corresponding author of the study, said in the statement. “Halogens occur on Mars in forms different from on the Earth, and in much larger amounts, and we guessed that they would be important to the fate of manganese.”
The scientists, however, stress that although oxygen may not have been present in Mars’ ancient atmosphere after all, the planet still could have teemed with microscopic life forms in the past.
“There are several life forms even on Earth that do not require oxygen to survive,” Mitra said. “I don’t think of it as a ‘setback’ to habitability — only that there was probably no oxygen-based lifeforms.”
The study (opens in new tab) was published on Thursday (Dec. 22), in the journal Nature Geoscience.
Follow Tereza Pultarova on Twitter @TerezaPultarova. Follow us on Twitter @Spacedotcom and on Facebook.
Something weird is happening in Jupiter’s atmosphere
Something odd is happening in Jupiter’s atmosphere, a new study has revealed.
Forty years’ worth of measurements of Jupiter’s atmosphere by spacecraft and ground-based telescopes have revealed strange weather patterns on the largest planet of the solar system, including hot and cold periods during its long year (equivalent to 12 Earth years). But Jupiter isn’t going through seasonal changes like Earth does.
On Earth, weather transitions between winter, spring, summer and fall are a result of the tilt of the planet’s axis toward the plane in which it orbits the sun. This 23-degree tilt makes different parts of the globe receive varying amounts of sunlight throughout the year. But Jupiter‘s axis is tilted toward the giant planet’s orbital plane by only 3 degrees, meaning that the amount of sun rays reaching different parts of Jupiter’s surface throughout its long year barely changes. Still, the new study found periodic temperature swings taking place around the planet’s cloud-covered globe.
Related: Jupiter, too! New James Webb photos show giant planet’s rings, moons and more
“We’ve solved one part of the puzzle now, which is that the atmosphere shows these natural cycles,” Leigh Fletcher, an astronomer at the University of Leicester in the U.K. and a co-author of the new paper, said in a NASA statement (opens in new tab). “To understand what’s driving these patterns and why they occur on these particular timescales, we need to explore both above and below the cloudy layers.”
The team has found indications that these unseasonal seasons may have something to do with a phenomenon known as teleconnection. Teleconnection describes periodic changes in aspects of a planet’s atmospheric system that occur simultaneously in parts of the globe that are seemingly unconnected and could lie thousands of miles or kilometers apart.
Teleconnection has been observed in Earth’s atmosphere since the 19th century, most notably in the famous La Nina – El Nino cycle, also known as the Southern Oscillation. During these events, changes in the trade winds of the western Pacific Ocean correspond with changes in rainfall across much of North America, according to the National Oceanic and Atmospheric Administration (NOAA).
In the new research, the scientists found that on Jupiter, when temperatures rise at specific latitudes in the northern hemisphere, the same latitudes in the southern hemisphere cool off, almost like a perfect mirror image.
“That was the most surprising of all,” Glenn Orton, a planetary scientist at NASA’s Jet Propulsion Laboratory in California and lead author of the study, said in the statement.
“We found a connection between how the temperatures varied at very distant latitudes,” he said. “It’s similar to a phenomenon we see on Earth, where weather and climate patterns in one region can have a noticeable influence on weather elsewhere, with the patterns of variability seemingly ‘teleconnected’ across vast distances through the atmosphere.”
The measurements also revealed that when temperatures rise in the stratosphere, the upper layer of Jupiter’s atmosphere, they fall in the troposphere, the lowest atmospheric layer, where weather events occur, including Jupiter’s powerful storms.
The study included data from 1978 onward, gathered by some of the best ground-based telescopes, including the Very Large Telescope in Chile, NASA’s Infrared Telescope Facility and the Subaru Telescope at the Mauna Kea Observatories in Hawaii. The researchers also used data from spacecraft such as the deep-space Voyager probes, which flew past Jupiter in 1979, and the Cassini mission, which flew past Jupiter in 2001 on its way to explore Saturn.
“Measuring these temperature changes and periods over time is a step toward ultimately having a full-on Jupiter weather forecast, if we can connect cause and effect in Jupiter’s atmosphere,” Fletcher said in the statement. “And the even bigger-picture question is if we can someday extend this to other giant planets to see if similar patterns show up.”
Previously, scientists knew that Jupiter’s atmosphere features colder regions that appear in lighter colors and warmer regions that appear as brownish bands. The new study, which covers a period of three Jovian years, for the first time reveals how these patterns change over longer periods of time.
The study (opens in new tab) was published in the journal Nature Astronomy on Monday (Dec. 19).
Follow Tereza Pultarova on Twitter @TerezaPultarova. Follow us on Twitter @Spacedotcom and on Facebook.
We Just Got The Most Detailed View of an Exoplanet Atmosphere Yet
WASP-39b, a gas giant about 700 light-years away, is turning out to be quite the exoplanetary treasure.
Earlier this year, WASP-39b was the subject of the first-ever detection of carbon dioxide in the atmosphere of a planet outside the Solar System.
Now, an in-depth analysis of data from the James Webb Space Telescope (JWST) has given us an absolute goldmine of information: the most detailed look at an exoplanet atmosphere yet.
The results include information about WASP-39b’s clouds, the first-ever direct detection of photochemistry in an exoplanet atmosphere, and a nearly complete inventory of the atmosphere’s chemical contents that reveals tantalizing hints of the exoplanet’s formation history.
These epic discoveries have been published in five papers in Nature, and pave the way for the eventual detection of the chemical signatures of life outside the Solar System.
“These early observations are a harbinger of more amazing science to come with JWST,” says astrophysicist Laura Kreidberg, director of the Max Planck Institute for Astronomy in Germany.
“We put the telescope through its paces to test the performance, and it was nearly flawless – even better than we hoped.”
Since the first exoplanets were discovered in the early 1990s, we’ve sought to know more about these worlds orbiting alien stars.
But the challenges have been steep ones. Exoplanets can be extremely small and are extremely distant. We’ve never even seen most of them: We only know of their existence based on the effect they have on their host stars.
One of these effects occurs when the exoplanet passes between us and the star, an event known as a transit. This causes the starlight to slightly dim; periodic dimming events suggest the presence of an orbiting body. We can even tell how big that orbiting body is, based on the dimming and gravitational effects on the star.
And there’s something else we can tell, based on transit data. As starlight passes through the atmosphere of the transiting exoplanet, it changes. Some wavelengths on the spectrum are dimmed or brightened, depending on how molecules in the atmosphere absorb and re-emit light.
The signal is faint, but with a powerful enough telescope, and a stack of transits, the changing absorption and emission features on the spectrum can be decoded to determine the contents of an exoplanet’s atmosphere.
JWST is the most powerful space telescope ever launched. With three of its four instruments, it obtained detailed infrared spectra from the star WASP-39. Scientists then got to work analyzing the colorful codes.
First up was a census of the molecules present in WASP-39b’s atmosphere. In addition to the aforementioned carbon dioxide, the researchers detected water vapor, sodium, and carbon monoxide. There was no detection made of methane, implying that the metallicity of WASP-39b is higher than that of Earth.
The abundance of these elements is also revealing. In particular, the ratio of carbon to oxygen suggests that the exoplanet formed much farther from its host star than its current close-in position, occupying a four-day orbit. And modeling and observation data suggest that the exoplanet’s sky is populated by broken clouds – not of water, but of silicates and sulfites.
Finally, the observations revealed the presence of a compound called sulfur dioxide. Here in the Solar System, on rocky worlds such as Venus and Jovian moon Io, sulfur dioxide is the result of volcanic activity. But on gas worlds, sulfur dioxide has a different origin story: It’s produced when hydrogen sulfide is broken down by light into its constituent parts, and the resulting sulfur is oxidized.
Photon-induced chemical reactions are known as photochemistry, and they have implications for habitability, the stability of an atmosphere, and the formation of aerosols.
WASP-39b, to be clear, is not likely to be habitable to life as we know it for a whole bunch of reasons, including but not limited to its scorching temperature and gaseous makeup, but the detection of photochemistry is one that has implications for atmospheric studies of other worlds, and understanding the evolution of WASP-39b itself.
Planetary scientists have been gearing up for years for the insights into atmospheres that JWST was expected to provide. With the first detailed exoplanet atmosphere analysis, it seems that the space telescope is going to live up to its promise.
In addition, the teams involved in this research are preparing documentation so other scientists can apply their techniques to future JWST exoplanet observations.
We may not detect the signatures of life in an exoplanet atmosphere with JWST – perhaps an even more powerful telescope will be required to deliver that level of fine detail – but with the analysis of WASP-39b, that discovery is feeling ever more tantalizingly within grasp.
“Data like these,” says astronomer Natalie Batalha of the University of California Santa Cruz, “are a game changer.”
The research will be published Nature and can be read in preprints here, here, here, here, and here.
Juno probe snaps photo of Jupiter’s atmosphere, 2 big moons
A flyby of Jupiter by NASA’s Juno spacecraft has delivered a stunning image of the gas giant’s cloud tops and the moons Callisto and Io.
The newly released image was taken by the spacecraft’s JunoCam just under a year ago, on Nov. 29, 2021, as the Jupiter-exploring Juno completed its 38th close flyby of our solar system’s largest planet.
The image shows the arc of Jupiter’s horizon and the planet’s churning, rippling clouds, while also capturing the moons Io (above) and Callisto (below).
Photos: Jupiter, the solar system’s largest planet
The image was taken when Juno was about 8,700 miles (14,000 kilometers) above Jupiter’s cloud tops, at a latitude of about 69 degrees, traveling at a speed of about 123,000 mph (198,000 kph) relative to the planet, according to a NASA statement.
Citizen scientist Gerald Eichstädt used raw JunoCam data to make the original version of this image. Another citizen scientist, Thomas Thomopoulos, then further processed it, zooming in and making color enhancements, NASA stated.
Juno recently made a flyby of another one of Jupiter’s four big Galilean moons, the ice-covered, ocean world of Europa, returning the first close-up images of the moon in more than 20 years. Juno also got up close to the fourth Galilean moon, Ganymede, in April 2021, delivering impressive images of the solar system’s largest moon during that flyby.
The close approaches don’t stop there. The Juno spacecraft — which launched in 2011 and arrived at Jupiter in 2016 — is next scheduled to make flybys of the violently volcanic world of Io in December 2023 and February 2024.
NASA notes that JunoCam’s raw images are available for the public to peruse and process here (opens in new tab), with more information about NASA citizen science to be found here (opens in new tab).
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Webb Telescope Reveals Noxious Atmosphere of a Planet 700 Light-Years Away
Astrophysicists on Earth are no strangers to WASP-39b, an exoplanet orbiting a star about 700 light-years from Earth, though they’ve never actually seen it directly. Now, the Webb Space Telescope has offered fresh insight into this distant world: Its observations have revealed the recipe list for the planet’s toxic atmosphere.
WASP-39b is a gas giant about the mass of Saturn and the size of Jupiter, but it orbits its star at about the same distance as Mercury is from the Sun, making the exoplanet very, very hot. The exoplanet was discovered in 2011; earlier this year, Webb telescope observations revealed carbon dioxide lurking in its atmosphere.
More molecules and chemical compounds have now been indentified, including evidence of water, sulfur dioxide, carbon monoxide, sodium, and potassium. The findings are under review for publication and currently available on the preprint server arXiv.
“This is the first time we have seen concrete evidence of photochemistry — chemical reactions initiated by energetic stellar light — on exoplanets,” said Shang-Min Tsai, a researcher at the University of Oxford lead author of the paper explaining sulfur dioxide’s presence in the planet’s atmosphere, in a European Space Agency release. “I see this as a really promising outlook for advancing our understanding of exoplanet atmospheres with [this mission].”
It’s no small feat to sniff out the chemicals floating in the atmosphere of a distant world. The nearest confirmed exoplanet is 24.9 trillion miles away. Yet Webb managed to spot such infinitesimal molecules in WASP-39b.
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Webb observed the planet by waiting for it to transit in front of its host star; when it did, the star’s light illuminated the planet from behind. Webb picked up infrared wavelengths of that light, and scientists can deduce which chemicals are present in the atmosphere based on the wavelengths of light they absorbed.
Webb’s capabilities have broader implications for understanding the diversity of exoplanets in our galaxy, with an eye toward their potential habitability. With its extreme heat and gaseous composition, WASP-39b is certainly not hospitable to any life we know of—but it’s showcasing the kind of molecular-level analysis Webb can apply to distant worlds.
“I am looking forward to seeing what we find in the atmospheres of small, terrestrial planets,” said Mercedes López-Morales, an astronomer at the Center for Astrophysics | Harvard & Smithsonian and a co-author of the recent work, in the ESA release.
The data suggested to the researchers that the chemicals in the planet’s atmosphere may be broken up in clouds, rather than evenly distributed in its atmosphere. And based on the relative abundances of the chemicals in the atmosphere, the researchers think that WASP-39b emerged from a glomming together of planetesimals over time.
While we don’t know where Webb will turn its infrared gaze next, we know that, at some point, more exoplanets will be on the docket. Webb has already investigated the atmospheres of rocky planets in the TRAPPIST-1 system, and may return to the system in due time. You can keep up with Webb’s most recent targets here.
More: Webb Telescope Brings a Once-Fuzzy Galaxy Into Focus
James Webb Space Telescope reveals alien planet’s atmosphere like never before
A boiling Saturn-like planet 700 light-years away from the sun has become the best-explored planet outside our solar system. The James Webb Space Telescope’s measurements of the planet’s atmosphere have revealed unprecedented details of its chemistry, and even allowed astronomers to test methods for detecting alien life.
The exoplanet WASP-39b, which orbits a star in the constellation Virgo, made headlines in late August when the James Webb Space Telescope (Webb or JWST) found carbon dioxide in its atmosphere. It was the first ever such detection and experts hailed the finding as a major breakthrough. Now, less than three months later, an avalanche of studies based on the grand telescope’s observations have revealed the most minute details of WASP-39b’s atmosphere, which even enabled astronomers to make conclusions about the exoplanet’s formation history.
“These early observations are a harbinger of more amazing science to come with JWST,” Laura Kreidberg, director of the Max Planck Institute for Astronomy (MPIA) in Germany who was involved in the observations, said in a statement. “We put the telescope through its paces to test the performance, and it was nearly flawless — even better than we hoped.”
Related: James Webb Space Telescope snags its 1st direct photo of an alien world
Astronomers used three out of Webb’s four instruments to observe the distant planet: the main NIRCam camera and the two spectroscopes NIRISS and NIRSpec, which split light from the observed objects into light spectra, the barcode-like fingerprints that reveal the chemical compositions of the observed planets and stars.
The observations revealed that WASP-39b is shrouded in thick clouds containing sulfur and silicates. These chemicals interact with the light of the parent star, producing sulfur dioxide in a reaction similar to the one that produces ozone in Earth’s atmosphere.
WASP-39b is a gas giant about one-third the size of the solar system‘s largest planet, Jupiter, and orbits only 4.3 million miles (7 million kilometers) away from its parent star, or eight times closer than the distance of the solar system’s innermost planet Mercury from the sun.
The sheer intensity of starlight that batters WASP-39b makes the planet an ideal laboratory for studying such photochemical reactions, scientists said in the statement.
The level of detail provided by JWST allowed astronomers to peek into WASP-39b’s past and learn how this hot and scorching world came into being. From the ratios of carbon to oxygen, of potassium to oxygen, and of sulfur to hydrogen in the planet’s atmosphere, the researchers inferred that the gas giant planet must have formed from collisions of several smaller planetesimals. In addition, the much higher abundance of oxygen compared to carbon in the thick clouds revealed that WASP-39b formed much farther away from its star than it orbits today.
“Data like these are a game changer,” Natalia Batalha, a professor of astronomy and astrophysics at the University of California at Santa Cruz who coordinated the observing program, said in the statement.
The observations even allowed astronomers to test methods that one day could help detect life on other exoplanets. That detection would rely on a similar atmospheric analysis as conducted on WASP-39b, then compare the results with models of alien planets. If the planet displays more oxygen than those models predict, for example, it could be a sign of life.
WASP-39b, however, due to its proximity to its parent star, is an improbable candidate to host extraterrestrial life as temperature on the planet soars to an unlivable 1,650 degrees Fahrenheit (900 degrees Celsius).
Five new studies (1,2,3,4,5) based on JWST data are under review or in press with the journal Nature.
Follow Tereza Pultarova on Twitter @TerezaPultarova. Follow us on Twitter @Spacedotcom and on Facebook.
Unabated Carbon Is Shrinking Earth’s Upper Atmosphere, Scientists Warn : ScienceAlert
Rising levels of carbon dioxide in Earth’s atmosphere could exacerbate efforts to clean up our increasingly cluttered shell of orbiting space junk.
According to two new studies, the greenhouse gas has significantly contributed to the contraction of the upper atmosphere. This contraction has been hypothesized for decades; now, for the first time, it’s been actually observed.
Some of the observed shrinkage is normal, and will bounce back; but the contribution made by CO2 is, scientists say, probably permanent.
This means that defunct satellites and other bits of old technology in low Earth orbit is likely to remain in place longer due to the reduction of atmospheric drag, cluttering up the region and causing problems for newer satellites and space observations.
“One consequence is satellites will stay up longer, which is great, because people want their satellites to stay up,” explains geospace scientist Martin Mlynczak of NASA’s Langley Research Center.
“But debris will also stay up longer and likely increase the probability that satellites and other valuable space objects will need to adjust their path to avoid collisions.”
Descriptions of Earth’s atmosphere generally set the layers at specific altitudes, but the truth is that the volume of gases surrounding our world isn’t static. It expands and contracts in response to various influences, the biggest of which is probably the Sun.
Now, the Sun isn’t static either. It goes through cycles of activity, from high, to low, and back again, roughly every 11 years. We’re currently amid the 25th such cycle since reckoning began, a cycle that started around December 2019. The previous cycle, number 24, was unusually subdued even at the peak of solar activity, and this is what enabled Mlynczak and his colleagues to take measurements of atmospheric contraction.
Their attention was focused on two layers, collectively known as the MLT: the mesosphere, which starts at about 60 kilometers (37 miles) altitude; and the lower thermosphere, which starts at around 90 kilometers.
Data from NASA’s TIMED satellite, an observatory collecting data on the upper atmosphere, gave them pressure and temperature information for the MLT for a nearly 20-year period, from 2002 to 2021.
In some lower layers of the atmosphere, CO2 creates a warming effect by absorbing and re-emitting infrared radiation in all directions, effectively trapping a portion of it.
Up in the much, much thinner MLT, however, some of the infrared radiation emitted by CO2 escapes into space, effectively carrying away heat and cooling the upper atmosphere. The higher the CO2, the cooler the atmosphere.
We already knew this cooling is causing the stratosphere to contract. Now we can see it’s doing the same to the mesosphere and thermosphere above it too. Using the data from TIMED, Mlynczak and his team found that the MLT contracted by about 1,333 meters (4,373 feet). Approximately 342 meters of that is the result of CO2-induced radiative cooling.
“There’s been a lot of interest in seeing if we can actually observe this cooling and shrinking effect on the atmosphere,” Mlynczak says.
“We finally present those observations in this paper. We’re the first to show the shrinking of the atmosphere like this, on a global basis.”
Given that the thermosphere extends out to several hundred kilometers, that 342 meters might not seem like a lot. However, a paper published in September by physicist Ingrid Cnossen of the British Antarctic Survey in the UK showed that thermospheric cooling could result in a 33 percent reduction in atmospheric drag by 2070.
Atmospheric drag is what helps satellites and rocket stages deorbit after their missions end. This reduction in drag could prolong the orbital lifespan of defunct space junk by 30 percent by 2070, Cnossen found.
As more and more satellites are launched into low-Earth orbit, this is going to become an increasing problem, with no real mitigation measures in sight – either to decrease the number of satellites, or the amount of CO2.
“At every altitude, there is a cooling and a contraction that we attribute in part to increasing carbon dioxide,” Mlynczak says. “As long as carbon dioxide increases at about the same rate, we can expect these rates of temperature change to stay about constant too, at about half a degree Kelvin [of cooling] per decade.”
The research has been published in Journal of Geophysical Research: Atmospheres.
Solar Sail Spacecraft About to Drop Through Earth’s Atmosphere
A tiny spacecraft is about to sail into its demise, burning up as it reenters Earth’s atmosphere for the end of its mission.
The Planetary Society’s LightSail 2 has been getting dragged down by the pull of Earth’s atmosphere, and is expected to reenter the atmosphere within the next few days, the organization announced on Monday. When it does, the spacecraft will burn up, bringing its three and a half year journey of orbiting Earth to a fiery end.
“We always knew this would be the eventual fate for the spacecraft,” The Planetary Society wrote. “Despite the sadness at seeing it go, all those who worked on this project and the 50,000 individual donors who completely funded the LightSail program should reflect on this as a moment of pride.”
LightSail 2 launched in June 2019, unfurling its 344-square-foot (32-square-meter) solar sail a month after reaching its orbital post. The purpose of the mission was to test solar sailing as a way for spacecraft to travel.
Solar sails run on photons from the Sun, causing small bursts of momentum that propel the spacecraft. As the photons hit LightSail’s wings, the spacecraft was pushed further away from the Sun, reaching higher altitudes. Just two weeks after spreading its wings, LightSail 2 gained 2 miles (3.2 kilometers) of altitude, making this experiment a success.
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The mission has even far exceeded its initial one year timeline, and has been orbiting Earth for 3.5 years, completing 18,000 orbits, and covering 5 million miles (8 million kilometers). But for the past few months, LightSail 2 started losing altitude at an increasing rate.
The spacecraft has been the victim of atmospheric drag, causing LightSail 2 to slow down as it smashed into atmospheric particles during its orbit. The Sun also played a part in LightSail 2’s demise, heating up Earth’s upper atmosphere, and causing it to become denser, which slowed down the spacecraft.
The mission also suffered from communication glitches due to faulty equipment at the ground station. During times of communication drop-off, the team was unable to send data to the spacecraft, causing its sailing to slightly suffer.
After sinking lower through Earth’s atmosphere, the spacecraft will eventually reenter the atmosphere. During reentry, LightSail 2 will be moving so quickly that it will create an energetic pressure wave ahead of it, causing the air around it to heat up and turn the spacecraft into a disintegrating ball of fire.
LightSail 2 may be coming to an end, but the experiment has already inspired a new generation of spacecraft. Those spacecraft include NASA’s NEA Scout mission to a near-Earth asteroid (scheduled for launch in August), NASA’s Advanced Composite Solar Sail System to test out sail boom material in Earth orbit (scheduled for launch sometime mid-2022), and NASA’s Solar Cruiser (scheduled for a 2025 launch).
We’ll be looking out for LightSail’s fiery reentry, bidding farewell to the long-running solar sailor.
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