NASA scientist, Dr. David S. McKay has passed away. He may be best known for his paper about a Martian meteorite, ALH84001, which presented an argument that it contained evidence for life on Mars. McKay had been battling serious cardiac health problems for some time, according to an announcement from Johnson Space Center, and he died peacefully in his sleep in the early morning hours of February 20, 2013.
McKay had been the Chief Scientist For Astrobiology at NASA and searched for evidence of past life on Mars using Martian meteorites and terrestrial analogs. He performed original research on lunar soils, lunar pyroclastics, and space weathering.
McKay joined NASA in June of 1965 and participated extensively in astronaut training up until the Apollo 11 mission. He was named a Principal Investigator to study the first returned lunar samples and continued as a lunar sample PI for the next 20 years. He started many of the laboratories for the Lunar Sample Facility at Johnson Space Center and managed the NASA space resources program out of JSC during much of the 1980s.
McKay published more than 200 peer-reviewed papers on lunar samples, space resource utilization, cosmic dust, meteorites, astrobiology and Mars topics, and NASA said his “body of work includes many contributions to our understanding of the development and evolution of the lunar regolith and space weathering processes.”
Most notably, he was the lead author on the 1996 paper in Science on the ALH84001 Martian meteorite that was found in Antarctica and argued that it contains evidence for life on Mars.
“Although that claim was highly controversial, there can be no question that the appearance of that paper sparked significant changes in martian and planetary science, shaped the direction of the Mars Exploration Program to the present day, and prompted the establishment of the NASA Astrobiology Institute,” said the JSC announcement. “Whether one accepts their arguments or not, it has led, directly or indirectly, to investigations seeking and finding signs of life in the most extreme environments. History will judge the value of that rather serendipitous outcome, but it seems clear that its significance is, and will remain, great.”
Sunspot 1678 in Hydrogen alpha light, taken on February 19, 2013. Credit and copyright: Paul Andrew.
On February 19 and 20, 2013, scientists watched a giant sunspot form in under 48 hours. It has grown to over six Earth diameters. This image by astrophotographer Paul Andrew shows a detailed, close-up view of this sunspot group, named AR 1678, imaged with a hydrogen alpha filter.
NASA said the spot quickly evolved into what’s called a delta region, which has a magnetic field that harbors energy for strong solar flares. NOAA forecasters estimate a 45% chance of M-flares and a 15% chance of X-flares during the next day.
Below is an image from the Solar Dynamics Observatory of this region on the Sun:
This image of AR 1678 combines images from two instruments on NASA’s Solar Dynamics Observatory (SDO): the Helioseismic and Magnetic Imager (HMI), which takes pictures in visible light that show sunspots and the Advanced Imaging Assembly (AIA), which took an image in the 304 Angstrom wavelength showing the lower atmosphere of the sun, which is colorized in red. Credit: NASA/SDO/AIA/HMI/Goddard Space Flight Center
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This illustration shows the disk of our Milky Way galaxy, surrounded by a faint, extended halo of old stars. Astronomers using the Hubble Space Telescope to observe the nearby Andromeda galaxy serendipitously identified a dozen foreground stars in the Milky Way halo. They measured the first sideways motions (represented by the arrows) for such distant halo stars. The motions indicate the possible presence of a shell in the halo, which may have formed from the accretion of a dwarf galaxy. This observation supports the view that the Milky Way has undergone continuing growth and evolution over its lifetime by consuming smaller galaxies.
Illustration Credit: NASA, ESA, and A. Feild (STScI)
Like tantalizing tidbits stored in the vast recesses of one’s refrigerator, astronomers using NASA’s Hubble Space Telescope have evidence of a shell of stars left over from one of the Milky Way’s meals. In a study which will appear in an upcoming issue of the Astrophysical Journal researchers have revealed a group of stars moving sideways – a motion which points to the fact our galaxy may have consumed another during its evolution.
“Hubble’s unique capabilities are allowing astronomers to uncover clues to the galaxy’s remote past. The more distant regions of the galaxy have evolved more slowly than the inner sections. Objects in the outer regions still bear the signatures of events that happened long ago,” said Roeland van der Marel of the Space Telescope Science Institute (STScI) in Baltimore, Maryland.
As curious as this shell of stars is, they offer even more information by revealing a chance to study the mysterious hidden mass of Milky Way – dark matter. With more than a hundred billion galaxies spread over the Universe, what better place to get a closer look than right here at home? The team of astronomers led by Alis Deason of the University of California, Santa Cruz, and van der Marel studied the outer halo, a region roughly 80,000 light years from our galaxy’s center, and identified 13 stars which may have come to light at the very beginning of the Milky Way’s formation.
What’s so special about this group of geriatric suns? In this case, it’s their movement. Instead of cruising along in a radial orbit, these elderly stars show tangential motion – an unexpected observation. Normally halo stars travel towards the galactic center, only to return outwards again. What could cause this double handful of stars to move differently? The research team speculates there could be an “over-density” of stars at the 80,000 light year mark.
As intriguing as these stars are, this strange shell was discovered somewhat by accident. Deason and her team winnowed out the outer halo stars from a seven year study of archival images taken by the Hubble telescope of the Andromeda galaxy. While looking some twenty times further away at our neighboring galaxy’s stars, these strange moving stars came to light as foreground objects… objects that “cluttered” the images. While these halo stars were bad for that particular study, they were very good for Deason and the team. It gave them the chance to take a really close look at the motion of the Milky Way’s halo stars.
However, seeing these stars wasn’t easy. Thanks to Hubble’s incredible resolution and light gathering power, each image contained more than 100,000 individual stars. “We had to somehow find those few stars that actually belonged to the Milky Way halo,” van der Marel said. “It was like finding needles in a haystack.”
So how did the astronomers separate the shell stars from those that belonged to the outer fringes of the Andromeda? The initial observations picked the stars out based on their color, brightness and sideways motion. Thanks to parallax, our halo stars seem to move far faster simply because they are closer. Through the work of team member Tony Sohn of STSci, these revolutionary stars were identified and measured. Their tangential motion was observed and recorded with five percent precision. Not a speedy process when you consider these shell stars only move across the sky at a rate of about one milliarcsecond per year!
“Measurements of this accuracy are enabled by a combination of Hubble’s sharp view, the many years’ worth of observations, and the telescope’s stability. Hubble is located in the space environment, and it’s free of gravity, wind, atmosphere, and seismic perturbations,” van der Marel said.
What makes the team so confident in their findings? As we know, stars at home in our galaxy’s inner halo have highly radial orbits. When a comparison was made between the sideways motion of the outer halo stars with the inner motions, the researchers found equality. According to computer simulations of galaxy formation, outer stars should continue to have radial motion as they move outward into the halo, but these new findings prove opposite. What could cause it? A natural explanation would be an accretion event involving a satellite galaxy.
To further substantiate their findings, the team compared their results with data taken by the Sloan Digital Sky Survey involving halo stars. It was a eureka moment. The observations taken by the SDSS revealed a higher density of stars at roughly the same distance as the shell-shocked travelers. And the Milky Way isn’t alone. Other studies of halo stars involved in both the Triangulum and Andromeda show a large number of halo stars existing to a certain point – only to drop off. Deason realized this wasn’t just a weird coincidence. “What may be happening is that the stars are moving quite slowly because they are at the apocenter, the farthest point in their orbit about the hub of our Milky Way,” Deason explained. “The slowdown creates a pileup of stars as they loop around in their path and travel back towards the galaxy. So their in and out or radial motion decreases compared with their sideways or tangential motion.”
As exciting as these findings are, they aren’t news. Shell stars have been observed in the halos of other galaxies and were predicted to be part of the Milky Way. By nature, they should have been there – but they were simply to dim and too far-flung to make astronomers positive of their presence. Not any more. Now that astronomers know what to look for, they are even more anxious to dig into Hubble’s archives. “These unexpected results fuel our interest in looking for more stars to confirm that this is really happening,” Deason said. “At the moment we have quite a small sample. So we really can make it a lot more robust with getting more fields with Hubble.” The Andromeda observations only cover a very small “keyhole view” of the sky.
So what’s next? Now the team can paint an even more fine portrait of the Milky Way’s evolutionary history. By understanding the motions and orbits of the “shell” of stars in the halo, they might even by able to give us a accurate mass. “Until now, what we have been missing is the stars’ tangential motion, which is a key component. The tangential motion will allow us to better measure the total mass distribution of the galaxy, which is dominated by dark matter. By studying the mass distribution, we can see whether it follows the same distribution as predicted in theories of structure formation,” Deason said.
Lava flows on Mt. Etna visible from the The Advanced Land Imager (ALI) on the Earth Observing-1 (EO-1) satellite captured Etna on February 19, 2013. Credit: NASA
Italy’s Mount Etna has turned on again, spewing lava and gas in its first big eruption in 2013. The volcano is one of the most active in the world, and is Europe’s tallest active volcano, currently standing about 3,329 m (10,922 ft) high.
The volcano has been “simmering” for 10 months, but on February 19 and 20, the famous volcano came to life, providing dramatic visuals from the ground (see the video below) as well as from space, with three outbursts in less than 36 hours. This image from the Advanced Land Imager (ALI) on the Earth Observing-1 (EO-1) satellite captured Etna on February 19 at 9:59 a.m. Central European Time, about 3 hours after the end of the first outbursts.
The false-color image combines shortwave infrared, near infrared, and green light in the red, green, and blue channels of an RGB picture. This combination differentiates the appearance of fresh lava, snow, clouds, and forest.
Fresh lava is bright red—the hot surface emits enough energy to saturate the instrument’s shortwave infrared detectors, but is dark in near infrared and green light. Snow is blue-green, because it absorbs shortwave infrared light, but reflects near infrared and green light. Clouds made of water droplets (not ice crystals) reflect all three wavelengths of light similarly, and are white. Forests and other vegetation reflect near infrared more strongly than shortwave infrared and green light, and appear green. Dark gray areas are lightly vegetated lava flows, 30 to 350 years old.
The video from the ground was captured by Klaus Dorschfeldt, a videographer and webmaster at Italy’s National Institute of Geophysics and Volcanology.
In an update today on the Italian National Institute of Geophysics and Vocanology website, a fourth episode of lava fountains was reported. “Like the previous paroxysms, this event produced fountains and lava and an ash cloud that has shifted to the northern sector of the volcano.”
Bruce McCandless testing out the ultimate jetpack during STS-41B in February 1984. Credit: NASA
The official name is “extra-vehicular activity,” (EVA) but most of us like to call it a spacewalk. However, when you think about it, you don’t really walk in space. You float.
Or more properly speaking, clutch on to handlebars as you make your way from spot to spot on your spacecraft as you race against the clock to finish your repair or whatever outdoor tasks you were assigned. But hey, the view more than makes up for the hard work.
Some astronauts actually got to fly during their time “outside.” During STS-41B 29 years ago this month, Bruce McCandless was the first one to strap on a jetpack and, in science fiction style, float a little distance away from the shuttle.
He called his test of the manned maneuvering unit “a heck of a big leap”. Nearly 30 years after the fact, it still looks like a gutsy move.
What other memorable floating NASA spacewalks have we seen during the space age? Here are some examples:
The first American one
Ed White did the first American spacewalk in 1965. Credit: NASA
The pictures for Ed White’s spacewalk on Gemini 4 still look amazing, nearly 48 years after the fact. The astronaut tumbled and spun during his 23-minute walk in space, and even tested out a small rocket gun until the gas ran out. When commander Jim McDivitt ordered him back inside, the astronaut said it was the saddest moment in his life.
The dancing-with-exhaustion one
Eugene Cernan during his spacewalk on Gemini 9. Credit: NASA
On Gemini 9, which took place the year after Gemini 4, Eugene Cernan was tasked with a spacewalk that was supposed to test out a backpack to let him move independently of the spacecraft.
Cernan, however, faced a lack of handholds and physical supports as he clambered outside towards the backpack. Putting it on took almost all the strength out of him, as he had nowhere to hold on to counterbalance himself.
“Lord, I was tired. My heart was motoring at about 155 beats per minute, I was sweating like a pig, the pickle was a pest, and I had yet to begin any real work,” Cernan wrote in his memoir, Last Man on the Moon, about the experience.
The situation worsened as his visor fogged up and Cernan struggled unsuccessfully to use the backpack. Cernan was so exhausted that he could barely get inside the spacecraft. “I was as weary as I had ever been in my life,” he wrote.
The three-astronauts-outside one
Three astronauts grab the Intelsat VI satellite during the STS-49 mission. Credit: NASA
Spacewalks traditionally (at least, in the shuttle and station era) happen in pairs, so that if one person runs into trouble there’s another to help him or her out. However, two astronauts working outside during STS-49 couldn’t get enough of a grip on the free-flying Intelsat VI satellite they were trying to fix. So NASA elected to do another spacewalk with a third man.
Pierre Thuot hung on the Canadarm while Richard Hieb and Thomas Akers attached their bodies to the payload bay. Having three men hanging on to the satellite provided enough purchase for the astronauts inside the shuttle to maneuver Endeavour to a spot where Intelsat VI could be attached to the payload bay.
The facing-electrical-shock one
Scott Parazynski repaired a damaged solar panel on the space station. Credit: NASA
In 2007, the astronauts of STS-120 unfolded a solar array on the International Space Station and saw — to everyone’s horror — that some panels were torn. Veteran spacewalker Scott Parazynski was dispatched to the rescue. He rode on the end of the Canadarm2, dangling above a live set of electrified panels, and carefully threaded in a repair.
In an interview with Parazynski that I did several years ago, I asked how he used his medical training while doing the repair. Parazynski quipped something along the lines of, “Well, the top thing in my mind was ‘First do no harm.’ ”
The International Space Station construction ones
Sunita Williams appears to touch the sun during this spacewalk on Expedition 35, which took place on the completed International Space Station. Credit: NASA
Spacewalks used to be something extra-special, something that only happened every missions or, on long-duration ones, maybe once. Building the International Space Station was different. The astronauts brought the pieces up in the shuttle and installed them themselves.
The station made spacewalking routine, or as routine such a dangerous endeavour can be. For that reason, an honorary mention goes to every mission that built the ISS.
What are your favorite EVAs? Feel free to add yours to the comments.
According to a press release posted on SpaceRef and NASAWatch, Dennis Tito — the first-ever space tourist — is planning to send a human mission to Mars in January 2018 on a round-trip journey lasting 501 days. The trip would be timed to take advantage of the launch ‘window’ when Mars and Earth reach a position in their respective orbits that offers the best trajectory between the two planets.
Reportedly, Tito has created a new nonprofit company called the Inspiration Mars Foundation to facilitate the mission. The mission is intended to “generate new knowledge, experience and momentum for the next great era of space exploration.”
(2/21/13 13:00 UTC) We have an update on this news below:
Tito, along with several other notable people from the space community will provide more information in a press conference set for Wednesday, February 27th. Also at the press conference will be Taber MacCallum and Jane Poynter who were members of the Biosphere-2 project, and who are with the Paragon Space Development Corporation, which creates life-support systems, and Jonathan Clark, a medical researcher at the National Space Biomedical Research Institute, who may discuss the dangers from radiation to humans in deep space. The press conference will be moderated by journalist Miles O’Brien.
Tito paid about $20 million to visit the International Space Station in 2001.
Another endeavor, the Mars One project, wants to create a human settlement on Mars by 2023.
UPDATE: Spaceflight expert Jeff Foust did a some digging, and posted some insights about this story in his NewSpace Journal. Foust obtained a copy of a paper Tito plans to present at the IEEE Aerospace Conference in March, which discusses conference, a crewed free-return Mars mission that would fly by Mars – no going into orbit or landing. Such a 501-day mission would launch in January 2018, “using a modified SpaceX Dragon spacecraft launched on a Falcon Heavy rocket,” Foust writes. “According to the paper, existing environmental control and life support system (ECLSS) technologies would allow such a spacecraft to support two people for the mission, although in Spartan condition. ‘Crew comfort is limited to survival needs only. For example, sponge baths are acceptable, with no need for showers,’ the paper states.”
One of the paper’s co-authors is NASA Ames director Pete Worden, the paper outlines how NASA would also have a role in this mission in terms of supporting key life support and thermal protection systems, even though this is a private-sector effort. No estimates of what such a mission would cost are included in the paper, but it does say it would be financed privately. The paper adds that if they miss this favorable 2018 opportunity, the next chance to take advantage of this lower energy trajectory would be in 2031.
Emily Coren is an accomplished illustrator and scientist, and she’s figured out how to bring those two skills together to make science easier to understand: science illustrations.
Emily completed a series last year on how adaptive optics works. This is the technology that increases the resolution of both telescopes and microscopes, and she gave us permission to reprint the series here on Universe Today.
Artist concept of the Glory spacecraft in Earth orbit. Credit: NASA Goddard Space Flight Center
NASA has released the findings from a panel that investigated the 2011 crash of the Glory spacecraft after it failed to reach orbit on board an Orbital Sciences Taurus XL rocket, falling into the Pacific Ocean. Early on, the problem was traced to the fairing – the clamshell nosecone that encapsulates the satellite as it travels through the atmosphere — which did not separate from the rocket, weighing the satellite down, preventing its flight toward orbit.
However, the mishap investigation board was not able to identify the definitive cause for the fairing system failure. The rocket and satellite weren’t recovered, so there was no physical evidence to examine. In short, the board confirmed the Taurus launch vehicle’s fairing system failed to open fully and caused the mishap. And the board’s report does recommend ways to prevent future problems associated with the joint system that makes up the fairing.
But the board’s complete report is not available for public release because it contains information restricted by U.S. International Traffic in Arms Regulations (ITAR) and information proprietary to the companies involved.
A similar technical glitch occurred during the 2009 launch of the Orbiting Carbon Observatory (OCO). A replacement, OCO-2 is scheduled to launch in 2014. NASA had originally planned to fly OCO-2 on a Taurus rocket, but changed its plans after the loss of Glory. OCO-2 will now launch on a United Launch Alliance Delta-II. But NASA and Orbital are continuing to investigate the fairing system.
Glory was going to be a three-year mission designed to improve our understanding of Earth’s climate by collecting data on the properties of natural and human-caused aerosols in Earth’s atmosphere and how they might affect climate change, as well as determining the Sun’s affect on climate by measuring the total solar energy entering Earth’s atmosphere.
Screenshot of a dazzling magnetic display on the Sun, a phenomenon known as coronal rain. Credit: NASA/SDO
This footage was obtained by the AIA instrument on the Solar Dynamics Observatory on July 19, 2012. It provides a stunning display of solar activity and shows how wildly different events on the Sun can be. Some come just with a solar flare, some with an additional ejection of solar material called a coronal mass ejection (CME), and some with complex moving structures in association with changes in magnetic field lines that loop up into the Sun’s atmosphere, the corona.
This eruption produced all three.
A moderately powerful solar flare exploded on the Sun’s lower right hand limb, sending out light and radiation. Next came a CME, which shot off to the right out into space. And then, the Sun treated viewers to one of its dazzling magnetic displays — a phenomenon known as coronal rain.
Over the course of the next day, hot plasma in the corona cooled and condensed along strong magnetic fields in the region. Magnetic fields, themselves, are invisible, but the charged plasma is forced to move along the lines, showing up brightly in the extreme ultraviolet wavelength of 304 Angstroms, which highlights material at a temperature of about 50,000 Kelvin. This plasma acts as a tracer, helping scientists watch the dance of magnetic fields on the Sun, outlining the fields as it slowly falls back to the solar surface.
SDO collected one frame every 12 seconds, and the movie plays at 30 frames per second, so each second in this video corresponds to 6 minutes of real time. The video covers 12:30 a.m. EDT to 10:00 p.m. EDT on July 19, 2012.
NASA's Kepler mission has discovered a new planetary system that is home to the smallest planet yet found around a star like our sun, approximately 210 light-years away in the constellation Lyra. Credit: NASA/Ames/JPL-Caltech
Scientists have discovered a new planet orbiting a Sun-like star, and the exoplanet is the smallest yet found in data from the Kepler mission. The planet, Kepler-37b, is smaller than Mercury, but slightly larger than Earth’s Moon. The planet’s discovery came from a collaboration between Kepler scientists and a consortium of international researchers who employ asteroseismology — measuring oscillations in the star’s brightness caused by continuous star-quakes, and turning those tiny variations in the star’s light into sounds.
“That’s basically listening to the star by measuring sound waves,” said Steve Kawaler, from Iowa State University in the US, and a member of the research team. “The bigger the star, the lower the frequency, or ‘pitch’ of its song.”
The measurements made by the astroseismologists allowed the Kepler research team to more accurately measure the tiny Kepler-37b, as well as revealing two other planets in the same planetary system: one slightly smaller than Earth and one twice as large.
While Kepler 37b is likely a rocky planet, this would not be a great place for humans to live. It’s likely very hot — with a smoldering surface and no atmosphere.
“Owing to its extremely small size, similar to that of the Earth’s moon, and highly irradiated surface, Kepler-37b is very likely a rocky planet with no atmosphere or water, similar to Mercury,” the team wrote in their paper, which was published this week in Nature. “The detection of such a small planet shows for the first time that stellar systems host planets much smaller as well as much larger than anything we see in our own Solar System.”
The host star, Kepler-37, is about 210 light-years from Earth in the constellation Lyra. All three planets orbit the star at less than the distance Mercury is to the Sun, suggesting they are very hot, inhospitable worlds. Kepler-37b orbits every 13 days at less than one-third Mercury’s distance from the Sun. The estimated surface temperature of this smoldering planet, at more than 800 degrees Fahrenheit (700 Kelvin), would be hot enough to melt the zinc in a penny. Kepler-37c and Kepler-37d, orbit every 21 days and 40 days, respectively.
Artist’s concept of Kepler-37b. The planet is slightly larger than our moon, measuring about one-third the size of Earth. Credit: NASA/Ames/JPL-Caltech
The size of the star must be known in order to measure the planet’s size accurately. To learn more about the properties of the star Kepler-37, scientists examined sound waves generated by the boiling motion beneath the surface of the star.
“The technique for stellar seismology is analogous to how geologists use seismic waves generated by earthquakes to probe the interior structure of Earth,” said Travis Metcalfe, who is part of the Kepler Asteroseismic Science Consortium.
The sound waves travel into the star and bring information back up to the surface. The waves cause oscillations that Kepler observes as a rapid flickering of the star’s brightness. The barely discernible, high-frequency oscillations in the brightness of small stars are the most difficult to measure. This is why most objects previously subjected to asteroseismic analysis are larger than the Sun.
“Studying these oscillations been done for a long time with our own Sun,” Metcalfe told Universe Today, “but the Kepler mission expanded that to hundreds of Sun-like stars. Kepler-37 is the coolest star, as well as the smallest star that has been measured with asterosiesmology.”
Kepler-37 has a radius just three-quarters of the Sun. Metcalfe said the radius of the star is known to 3 percent accuracy, which translates to exceptional accuracy in the planet’s size.
Metcalfe launched a non-profit organization to help raise research funds for the Kepler Asteroseismic Science Consortium. The Pale Blue Dot Project allows people to adopt a star to support asteroseismology, since there is no NASA funding for asteroseismology.
“Much of the expertise for this exists in Europe and not in the US, so as a cost saving measure NASA outsourced this particular research for the Kepler mission,” said Metcalfe, “and NASA can’t fund researchers in other countries.”
The Kepler spacecraft carries a photometer, or light meter, to measure changes in the brightness of the stars it is focusing on in the Cygnus region in the sky.
Kepler Mission Star Field. An image by Carter Roberts of the Eastbay Astronomical Society in Oakland, CA, showing the Milky Way region of the sky where the Kepler spacecraft/photometer is pointing. Each rectangle indicates the specific region of the sky covered by each CCD element of the Kepler photometer. There are a total of 42 CCD elements in pairs, each pair comprising a square. Credit: Carter Roberts / Eastbay Astronomical Society.
Metcalfe said this discovery took a long time to verify, as the signature of this very small exoplanet was hard to confirm, to make sure the signature wasn’t coming from other sources such as an eclipsing binary star.
Kawaler said Kepler is sending astronomers photometry data that’s “probably the best we’ll see in our lifetimes,” he said, adding that this latest discovery shows “we have a proven technology for finding small planets around other stars.”
“We uncovered a planet smaller than any in our solar system orbiting one of the few stars that is both bright and quiet, where signal detection was possible,” said Thomas Barclay, lead author of Nature paper. “This discovery shows close-in planets can be smaller, as well as much larger, than planets orbiting our sun.”
And are there more small planets like this out there, just waiting to be found?
As the team wrote in their paper, “While a sample of only one planet is too small to use for determination of occurrence rates it does lend weight to the belief that planet occurrence increases exponentially with decreasing planet size.”
