Posted on by Anne Minard

Glory Launch Gets Another Go

Credit: NASA/Randy Beaudoin, VAFB

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NASA will try again to launch its “climate change satellite” on Friday, following an attempt that was scrubbed on Feb. 23 due to technical issues with ground support equipment for the Taurus XL launch vehicle, shown at right.

The March 4 liftoff is targeted for just after 2 a.m. local time at the Vandenberg Air Force Base in California (5:09:43 a.m. eastern).

Two instruments aboard Glory will help address influences on Earth’s climate. The Total Irradiance Monitor led by Greg Kopp at the Boulder, Colorado-based Laboratory for Atmospheric and Space Physics will continue a decades-long measurement of the sun’s energy reaching Earth, and Raytheon’s Aerosol Polarimetry Sensor will track aerosols in Earth’s atmosphere. See a more detailed story about the mission.

NASA will stream coverage of the launch starting at 3:30 a.m. eastern time on March 4. Real-time updates of countdown and launch milestones will also be posted on NASA’s launch blog.

Source: NASA announcement via Eurekalert!

Posted on by Anne Minard

Meteorites May Have Delivered First Ammonia for Life on Earth

Researchers have teased ammonia of a carbon-containing meteorite from Antarctica, and propose that meteorites may have delivered that essential ingredient for life to an early Earth.

The results appear today in the Proceedings of the National Academy of Sciences, and add to a growing body of evidence that meteorites may have played a key role in the development of life here. The NASA graphic at left was released just last month, when researchers reported that meteorites may have also delivered Earth’s first left-hand amino acids.

A Renazzo stony meteorite. Credit: NASA

Lead author Sandra Pizzarello, of Arizona State University, and her colleagues note in the new paper that carbonaceous chondrites are asteroidal meteorites known to contain abundant organic materials.

“Given that meteorites and comets have reached the Earth since it formed, it has been proposed that the exogenous influx from these bodies provided the organic inventories necessary for the emergence of life,” they write.

The carbonaceous meteorites of the Renazzo-type family (CR) are known to be especially rich in small soluble organic molecules, such as the amino acids glycine and alanine. To test for the presence of ammonia, the researchers collected powder from the much-studied CR2 Grave Nunataks (GRA) 95229 meteorite and treated it with water at high temperature and pressure. They found that the treated powders emitted ammonia, NH4, an important precursor to complex biological molecules such as amino acids and DNA, into the surrounding water.

Next, the researchers analyzed the nitrogen atoms within the ammonia and determined that the atomic isotope did not match those currently found on Earth, eliminating the possibility that the ammonia resulted from contamination during the experiment. Researchers have struggled to pinpoint the origin of the ammonia responsible for triggering the formation of the first biomolecules on early Earth. The authors suggest that now, they may have found it.

“The findings appear to trace CR2 meteorites’ origin to cosmochemical regimes where ammonia was pervasive, and we speculate that their delivery to the early Earth could have fostered prebiotic molecular evolution,” they write.

Source: Pizzarello et al., Abundant ammonia in primitive asteroids and the case for a possible exobiology.

Posted on by Anne Minard

Meteorites Illuminate Mystery of Chromium in Earth’s Core

It’s generally assumed that the Earth’s overall composition is similar to that of chondritic meteorites, the primitive, undifferentiated building blocks of the solar system. But a new study in Science Express led by Frederic Moynier, of the University of California at Davis, seems to suggest that Earth is a bit of an oddball.

 

 

Thin section of a chondritic meteorite. Credit: NASA

Moynier and his colleagues analyzed the isotope signature of chromium in a variety of meteorites, and found that it differed from chromium’s signature in the mantle.

“We show through high-precision measurements of Cr stable isotopes in a range of meteorites, which deviate by up to ~0.4‰ from the bulk silicate Earth, that Cr depletion resulted from its partitioning into Earth’s core with a preferential enrichment in light isotopes,” the authors write. “Ab-initio calculations suggest that the isotopic signature was established at mid-mantle magma ocean depth as Earth accreted planetary embryos and progressively became more oxidized.”

Chromium’s origins. New evidence suggests that, in the early solar nebula (A), chromium isotopes were divided into two components, one containing light isotopes, the other heavy isotopes. In the early Earth (B), these components formed a homogeneous mixture. During core partitioning (C), the core became enriched with lighter chromium isotopes, and the mantle with heavier isotopes. Courtesy of Science/AAAS

The results point to a process known as “core partitioning,” rather than an alternative process involving the volatilization of certain chromium isotopes so that they would have escaped from the Earth’s mantle. Core partitioning took place early on Earth at high temperatures, when the core separated from the silicate earth, leaving the core with a distinct composition that is enriched with lighter chromium isotopes, notes William McDonough, from the University of Maryland at College Park, in an accompanying Perspective piece.

McDonough writes that chromium, Earth’s 10th most abundant element, is named for the Greek word for color and “adds green to emeralds, red to rubies, brilliance to plated metals, and corrosion-proof quality to stainless steels.” It is distributed roughly equally throughout the planet.

He says the new result “adds another investigative tool for understanding and documenting past and present planetary processes. For the cosmochemistry and meteoritics communities, the findings further bolster the view that the solar nebula was a heterogeneous mixture of different components.”

Source: Science. The McDonough paper will be published online today by the journal Science, at the Science Express website.

Posted on by Anne Minard

‘Climate Change Satellite’ Gets its Day in the Sun — Finally

Artist concept of the Glory spacecraft in Earth orbit. Credit: NASA Goddard Space Flight Center

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NASA is launching an Earth-orbiting satellite called Glory tomorrow that will tackle a highly charged question: How much can the sun contribute to climate change?

The lull in solar activity between solar cycles 23 and 24 lasted for two years, twice as long as expected. By mid-2009, well into the second year, predictions of global cooling — another Little Ice Age — dominated global warming skeptic blogs. Now Solar Cycle 24 is safely underway, but aside from the dramatic flare and rash of sunspots that erupted last week, it’s been wimpy. Tom Woods, a solar physicist at the Boulder, Colo.-based Laboratory for Atmospheric and Space Physics, says he expects a subdued maximum for Solar Cycle 24 (around 2013) and generally, weak solar cycles come in threes. Each known set of sluggish solar cycles in the past has coincided with bitterly cold winters in parts of the globe — especially Europe and North America.

The question is, with the level of greenhouse gases in the atmosphere from the burning of fossil fuels, would we even feel an extended solar minimum? That’s exactly what Glory will aim to find out.

Glory will launch shortly after 2 a.m. local time on Wednesday, Feb. 23 from the Vandenberg Air Force Base north of Santa Barbara, Calif. The six-foot (1.9 meter), 1,100-pound (525 kg) satellite will orbit for at least three years in Earth’s upper atmosphere, where it will monitor both the total solar energy that’s reaching Earth, and the airborne aerosols greeting the energy it when it gets here.

Aerosols include salt, mineral dust, soot, and smoke and come from a variety of sources – such as vehicle exhaust, campfires, volcanoes and even desert winds and sea spray. They can influence climate by absorbing and scattering light, and NASA scientists have said the range of uncertainty about their role in climate change is far greater than any doubt about greenhouse gases from fossil fuels. Raytheon’s Aerosol Polarimetry Sensor, an instrument mounted on the Earth-facing side of the spacecraft, will observe the movement of aerosols through the atmosphere over time, especially on a seasonal scale.

Glory’s sun-facing side will sport the Total Irradiance Monitor, which will measure the intensity of solar radiation at the top of Earth’s atmosphere, adding to a 32-year data set, to record the solar radiation reaching Earth.

Watch a short video on the data: Solar Variability and Total Solar Irradiance (LASP)

Four solar irradiance instruments are currently flying, including VIRGO, launched in 1995, and SORCE, sent into orbit in 2003. Three of those, though, have long exceeded their designed mission lifetimes and are deteriorating. The European PICARD mission, launched in 2010, and NASA’s Glory mission are the new guard.

Greg Kopp, a researcher also at the Laboratory for Atmospheric and Space Physics, is principal investigator on the Glory mission. He says the existing data has already helped researchers understand variations on the scale of the sun’s 11-year activity cycles. But in order to capture longer trends, observations must continue. And solar researchers are increasingly eager to quantify the sun’s role, given the global importance of the question.

“I’m fond of saying we should get closer to the votersphere,” says Daniel Baker, director of Boulder’s Laboratory for Atmospheric and Space Physics. “I can think of no problem that is more significant to humanity than understanding climate change.”

Follow the mission:

On Feb. 23, NASA TV coverage of the countdown will begin at 3:30 a.m. EST (12:30 a.m. PST). Liftoff is targeted for 5:09:43 a.m. EST (2:09:43 a.m. PST). Spacecraft separation from the Taurus occurs 13 minutes after launch. The briefings and launch coverage also will be streamed online.

Launch coverage of Glory countdown activities will appear on NASA’s launch blog starting at 3:30 a.m. EST (12:30 a.m. PST). Real-time updates of countdown milestones as well as streaming video clips highlighting launch preparations and liftoff will also be available.

See also NASA’s Glory page and the Laboratory for Atmospheric and Space Physics, at the University of Colorado at Boulder.

Posted on by Nancy Atkinson

As Seen from Space: Ghostly, Ethereal Island

The volcanic island Ostrov Shikotan as seen by The Advanced Land Imager (ALI) on NASA’s Earth Observing-1 (EO-1) satellite.

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Looking rather otherworldly, this haunting view of Shikotan-to island shows ghostly swirls of sea ice surrounding the snow-covered volcanic island. Also known as Ostrov Shikotan, this island is at the southern end of a volcanic archipelago called the Kuril Chain, which is part of the Pacific Ring of Fire. The chain stretches approximately 1,300 km (810 mi) northeast from Japan, off the coast of Russia. The Advanced Land Imager (ALI) on NASA’s Earth Observing-1 (EO-1) satellite captured this natural-color image of Shikotan on February 14, 2011.

When the ice around the island forms, it is shaped by the moving currents – giving it a swirly appearance. North of the western end of Shikotan, eddies have shaped the ice into rough circles.

The island’s rugged appearance comes from millions of years of volcanic and seismic activity, multiple tsunamis, and weathering from wind and rain. The total land area of Shikotan is 225 square km.

Although this island is a part of Russia, Japan maintains a claim to it as well. And although you wouldn’t guess it from this image, there are two different settlements of about 1,000 people each. The name of Shikotan derives from an ancient Japanese dialect and means “land with big communities.”

See a larger version of the image at NASA’s Earth Observatory website.

Posted on by Anne Minard

First-Time Solar System Mosaic From the Inside Out

MESSENGER's new solar system portrait, from the inside out

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Say cheese! The MESSENGER spacecraft has captured the first portrait of our Solar System from the inside looking out. The images, captured Nov. 3 and 16, 2010, were snapped with the Wide Angle Camera (WAC) and Narrow Angle Camera (NAC) of MESSENGER’s Mercury Dual Imaging System (MDIS).

All of the planets are visible except for Uranus and Neptune, which at distances of 3.0 and 4.4 billion kilometers were too faint to detect with even the longest camera exposure time of 10 seconds. Their positions are indicated. The dwarf-planet Pluto, smaller and farther away, would have been even more difficult to observe.

Earth’s Moon and Jupiter’s Galilean satellites (Callisto, Ganymede, Europa, and Io) can be seen in the NAC image insets. Our Solar System’s perch on a spiral arm provided a beautiful view of part of the Milky Way galaxy, bottom center.

The following is a graphic showing the positions of the planets when the graphic was acquired:

The new mosaic provides a complement to the Solar System portrait – that one from the outside looking in – taken by Voyager 1 in 1990.

These six narrow-angle color images were made from the first ever 'portrait' of the solar system taken by Voyager 1, which was more than 4 billion miles from Earth and about 32 degrees above the ecliptic. The spacecraft acquired a total of 60 frames for a mosaic of the solar system which shows six of the planets. Mercury is too close to the sun to be seen. Mars was not detectable by the Voyager cameras due to scattered sunlight in the optics, and Pluto was not included in the mosaic because of its small size and distance from the sun. These blown-up images, left to right and top to bottom are Venus, Earth, Jupiter, and Saturn, Uranus, Neptune. The background features in the images are artifacts resulting from the magnification. The images were taken through three color filters -- violet, blue and green -- and recombined to produce the color images. Jupiter and Saturn were resolved by the camera but Uranus and Neptune appear larger than they really are because of image smear due to spacecraft motion during the long (15 second) exposure times. Earth appears to be in a band of light because it coincidentally lies right in the center of the scattered light rays resulting from taking the image so close to the sun. Earth was a crescent only 0.12 pixels in size. Venus was 0.11 pixel in diameter. The planetary images were taken with the narrow-angle camera (1500 mm focal length). Credit: NASA/JPL

“Obtaining this portrait was a terrific feat by the MESSENGER team,” says Sean Solomon, MESSENGER principal investigator and a researcher at the Carnegie Institution. “This snapshot of our neighborhood also reminds us that Earth is a member of a planetary family that was formed by common processes four and a half billion years ago. Our spacecraft is soon to orbit the innermost member of the family, one that holds many new answers to how Earth-like planets are assembled and evolve.”

Source: MESSENGER

Posted on by Ken Kremer

Sun Erupts with Enormous X2 Solar Flare

Active region 1158 let loose with an X2.2 flare late on February 15, taken by NASA's Solar Dynamics Observatory in the extreme ultraviolet wavelength of 193 Angstroms. Much of the vertical line in the image is caused by the bright flash overwhelming the SDO imager. Credit: NASA/SDO

Just in time for Valentine’s Day, [and the Stardust flyby of Comet Tempel 1] the Sun erupted with a massive X-Class flare, the most powerful of all solar events on February 14 at 8:56 p.m. EST . This was the first X-Class flare in Solar Cycle 24 and the most powerful X-ray flare in more than four years.

The video above shows the flare as imaged by the AIA instrument at 304 Angstroms on NASA’s Solar Dynamics Observatory. More graphic videos below show the flare in the extreme ultraviolet wavelength of 193 Angstroms and as a composite with SOHO’s coronagraph.

Spaceweather Update: A CME hit Earth’s magnetic field at approximately 0100 UT on Feb. 18th (8:00 pm EST on Feb. 17th). Send me or comment your aurora photos

The eruption registered X2 on the Richter scale of solar flares and originated from Active Region 1138 in the sun’s southern hemisphere. The flare directly follows several M-class and C-class flares over the past few days which were less powerful. The explosion also let loose a coronal mass ejection (CME) headed for Earth’s orbit. It was speeding at about 900 Km/second.
CME’s can disrupt communications systems and the electrical power grid and cause long lasting radiation storms.

According to a new SDO update, the particle cloud from this solar storm is weaker than first expected and may produce some beautiful aurora in the high northern and southern latitudes on Feb. 17 (tonight).

According to spaceweather.com, skywatchers in the high latitudes should be alert for auroras after nightfall Feb. 17 from this moderately strong geomagnetic storm.

Send me your aurora reports and photos to post here

Sources: SDO website, spaceweather.com

NASA SDO – Big, Bright Flare February 15, 2011

Video Caption: Active region 1158 let loose with an X2.2 flare at 0153 UT or 8:50 pm ET on February 15, 2011, the largest flare since Dec. 2006 and the biggest flare so far in Solar Cycle 24. Active Region 1158 is in the southern hemisphere, which has been lagging the north in activity but now leads in big flares! The movie shows a close-up of the flaring region taken by the Solar Dynamics Observatory in the extreme ultraviolet wavelength of 193 Angstroms. Much of the vertical line in the image and the staggered lines making an “X” are caused by the bright flash overwhelming our imager. A coronal mass ejection was also associated with the flare. The movie shows activity over about two days (Feb. 13-15, 2011). Since the active region was facing Earth, there is a good chance that Earth will receive some effects from these events, with some possibility of mid-latitude aurora Feb. 16 – 18. Credit: NASA SDO

X2 flare Video combo from SDO and SOHO

Video caption: The X2 flare of Feb. 15, 2011 seen by SDO (in extreme ultraviolet light) enlarged and superimposed on SOHO’s coronagraph that shows the faint edge of a “halo” coronal mass ejection as it races away from the Sun. The video covers about 11 hours

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This image taken by SDO's AIA instrument at 171 Angstrom shows the current conditions of the quiet corona and upper transition region of the Sun. Credit: NASA/SDO/AIA
Posted on by Nancy Atkinson

Study: Thawing Permafrost Could Accelerate Global Warming

From a press release from the University of Colorado Boulder:

Up to two-thirds of Earth’s permafrost likely will disappear by 2200 as a result of warming temperatures, unleashing vast quantities of carbon into the atmosphere, says a new study by the University of Colorado Boulder’s Cooperative Institute for Research in Environmental Sciences (CIRES).

The carbon resides in permanently frozen ground that is beginning to thaw in high latitudes from warming temperatures, which will impact not only the climate but also international strategies to reduce fossil fuel emissions, said CU-Boulder’s Kevin Schaefer, lead study author. “If we want to hit a target carbon dioxide concentration, then we have to reduce fossil fuel emissions that much lower than previously thought to account for this additional carbon from the permafrost,” he said. “Otherwise we will end up with a warmer Earth than we want.”
Continue reading “Study: Thawing Permafrost Could Accelerate Global Warming”

Posted on by Ken Kremer

Stardust-NExT zooms by Comet Tempel 1 for Cosmic Encounter

Comet Tempel 1 imaged by NASA's Stardust on Feb 14, Valentine’s Day. NASA's Stardust-NExT mission took this image of comet Tempel 1 at 8:38 p.m. PST (11:38 p.m. EST) on Feb 14, 2011. . The comet was first visited by NASA's Deep Impact mission in 2005. Credit: NASA/JPL-Caltech/Cornell Update Feb 15: Beautifully sharp Comet images now being downlinked. New story upcoming.

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NASA’s Stardust-NExT comet chaser successfully zoomed by Comet Temple 1 exactly as planned a short while ago at 11:37 p.m. EST on Feb. 14.

The cosmic Valentine’s Day encounter between the icy comet and the aging probe went off without a hitch. Stardust snapped 72 science images as it raced by at over 10 km/sec or 24,000 MPH and they are all centered in the cameras field of view. The probe came within 181 km (112 miles) of the nucleus of the volatile comet.

The images are being transmitted back now and it will take a several hours until the highest resolution images are available for the science team and the public to see. The first few images from a distance of over a thousand miles can be seen here

Tempel 1 is the first comet to be visited twice by spaceships from Earth. The primary goal was to find out how much the comet has changed in the five years since she was last visited by NASA’s Deep Impact mission in 2005, says Joe Ververka of Cornell University, who is the principal investigator of the Stardust-NExT mission. Deep Impact delivered a 375 kg projectile which blasted the comet and created an impact crater and an enormous cloud of dust so that scientists could study the composition and interior of the comet.

“We are going to be seeing the comet just after its closest passage to the sun. We know the comet is changing because the ice melts. We hope to see old and new territory and the crater and complete the Deep Impact experiment.”

Stardust-NExT is a repurposed spacecraft. Initially christened as Stardust, the spaceships original task was to fly by Comet Wild 2 in 2004. It also collected priceless cometary dust particles from the coma which were safely parachuted back to Earth inside a return canister in 2006. High powered science analysis of the precious comet dust will help researchers discern the origin and evolution of our solar system.

Stardust-NExt approaching Comet Tempel 1.
Artist concept of NASA's Stardust-NExT mission, which will fly by Comet Tempel 1 on Feb. 14, 2011. Credit: NASA/JPL-Caltech/LMSS

Stardust was hurriedly snapping high resolution pictures every 6 seconds and collecting data on the dust environment during the period of closest approach which lasted just about 8 minutes. The anticipation was building after 12 years of hard work and a journey of some 6 Billion kilometers (3.5 Billion miles)

“The Stardust spacecraft did a fantastic job,” says Tim Larson, the Stardust-NExT mission project manager from the Jet Propulsion Laboratory (JPL), Pasadena, Calif. “Stardust has already flown past a asteroid and a comet and returned comet particles to Earth”

“Because of the flyby geometry the antenna was pointed away from earth during the encounter. Therefore all the science images and data was stored in computer memory on board until the spacecraft was rotated to point towards Earth about an hour after the flyby.”

Each image takes about 15 minutes to be transmitted back to Earth by the High Gain Antenna at a data rate of 15,800 bits per second and across about 300 million miles of space.

NASA had bracketed five special images from the closest range as the first ones to be sent back. Instead, the more distant images were sent first. It will take about 10 hours to receive all the images.

So everyone had to wait a few hours longer to see the fruit of their long labor. Most of the team from NASA, JPL and Lockheed Martin has been working on the mission for a dozen years since its inception.

“We had a great spacecraft and a great team,” says Ververka. “Apparently, everything worked perfectly. The hardest thing now is we have to wait a couple of hours before we see all the goodies stored on board.”

The entire flyby was carried out autonomously using a preprogrammed sequence of commands. Due to the vast distance from Earth there was no possibility for mission controllers to intervene in real time.

Confirmation of a successful fly by and science imaging was not received until about 20 minutes after the actual event at about 11:58 p.m. EST. The dust flux monitor also registered increased activity just as occurred during the earlier Stardust flyby of Comet Wild 2 in 2004.

The Stardust-NExT science briefing on NASA TV will be delayed a few hours, until perhaps about 4 p.m. EST

Check back here later at Universe Today, on Tuesday, Feb. 15 for continuing coverage of the Valentine’s Day encounter of Stardust-NExT with the icy, unpredictable and fascinating Comet Tempel 1

Comet Tempel 1 imaged by NASA's Stardust on Feb 14, Valentine’s Day.
NASA's Stardust-NExT mission took this image of comet Tempel 1 at 8:36 p.m. PST (11:36 p.m. EST) on Feb 14, 2011, from a distance of approximately 2200 km (1360 miles). The comet was first visited by NASA's Deep Impact mission in 2005. Credit: NASA/JPL-Caltech/Cornell
Stardust-NExT Spacecraft & Comet Tempel 1.
Artist rendering of upcoming flyby on February, 14, 2011. Credit: NASA

Stardust-NExT: 2 Comet Flybys with 1 Spacecraft.
Stardust-NExT made history on Valentine’s Day - February, 14, 2011 – Tempel 1 is the first comet to be visited twice by spacrecraft from Earth. Stardust has now successfully visited 2 comets and gathered science data: Comet Wild 2 in 2004 (left) and Comet Tempel 1 in 2011 (right). Artist renderings Credit: NASA. Collage: Ken Kremer.
Posted on by Nancy Atkinson

Mysterious Noctilucent Clouds As Seen from Space

Polar mesospheric clouds (PMCs) observed by the Ozone Monitoring Instrument (OMI) on the Aura satellite. Maps by Robert Simmon. Credit: NAS

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Mysterious “night shining” or noctilucent clouds are beautiful to behold, and are usually seen during the summertime, appearing at sunset. They are thin, wavy ice clouds that form at very high altitudes and reflect sunlight long after the Sun has dropped below the horizon. Scientists don’t know exactly why they form, but continue to observe them – both from Earth and from space. These images were taken by the Ozone Monitoring Instrument (OMI) on NASA’s Aura satellite.

Also called polar mesospheric clouds, they are puzzling scientists with their recent dramatic changes. They used to be considered rare, but now the clouds are growing brighter, are seen more frequently, are visible at lower and lower latitudes than ever before, and — as these satellite image reveal — they are now even appearing during the day.

Noctilucent clouds over Kendal Castle, England in June 2010. Credit: Stuart Atkinson

Noctilucent clouds form in an upper layer of the Earth‘s atmosphere called the mesosphere during the Northern Hemisphere’s summer – at an altitude of 80 km (50 miles). They can start forming as early as May, and extend through August. They can also be seen in high latitudes during the summer months in the Southern Hemisphere.

What could the observed changes mean? Some scientists believe they are a good gauge of even the tiniest changes in the atmosphere, as they are extremely sensitive to changes in atmospheric water vapor and temperature. The clouds form only when temperatures drop below -130 degrees Celsius (-200 Fahrenheit), when the scant amount of water high in the atmosphere freezes into ice clouds.

Scientist Matthew DeLand of Science Systems and Applications Inc. and NASA’s Goddard Space Flight Center has been monitoring polar mesospheric clouds with instruments that were actually designed to study ozone, including the OMI, which provides more detailed and frequent observations than previous instruments. This gives DeLand a way to refine his previous measurements of a long-term trend towards more and brighter noctilucent clouds linked to rising greenhouse gases.

These images at the top of this article show OMI measurements of polar mesospheric clouds on July 10, 2007. The clouds, detectable because they are the only things that reflect light in this part of the atmosphere, are shown in white and pink. The Aura satellite travels in a polar orbit, circling from south to north as the Earth turns beneath it. As a result, the satellite gets several opportunities to image the poles every day. This series of images shows the clouds over six consecutive orbits between 7:16 and 15:52 Universal Time. Throughout the day, a wide area of polar mesospheric clouds developed over northern Greenland and Canada, peaking around 10:30 UTC (the third orbit).

Another instrument observing these clouds is the Solar Backscatter Ultraviolet (SBUV) instruments, which have flown on seven different satellites over the past 32 years, and that wealth of data is showing how the clouds change throughout the day.

DeLand now has an index to help correct the SBUV measurement trends to account for the time of day. The correction allows him to develop a more accurate view of the long-term trend. Even with the corrections, the trend indicates that the atmosphere has been responding to increased greenhouse gases over the past 30 years.

The fact that polar mesospheric clouds are getting brighter suggests that the mesosphere is getting colder and more humid, says DeLand. Increasing greenhouse gases in the atmosphere could account for both phenomena.

Sources: NASA Earth Observatory, twice