News Article | November 4, 2015
Key scientific findings about Mars' atmosphere and its fate will be revealed by the National Aeronautics and Space Administration (NASA) on Nov. 5, 2015. The news conference will kick off at 2:00 PM EST (1900 GMT) and will be streamed live on the Space.com website. The conference will be held in NASA's Washington Headquarters at the James Webb Auditorium. NASA's planetary science director Jim Green will chair the upcoming event. Conference speakers will include Michael Meyer (Mars Exploration Program lead scientist at NASA Headquarters), Bruce Jakosky (MAVEN spacecraft's chief investigator at the Laboratory for Atmospheric and Space Physics or LASP at the University of Colorado), Jasper Halekas (MAVEN spacecraft's instrument lead for Solar Wind Ion Analyzer at the University of Iowa), Dave Brain, (MAVEN LASP co-investigator) and Yaxue Dong (MAVEN LASP science team member). Key details made by NASA's spacecraft MAVEN will be reported during the Nov. 5 press conference. MAVEN stands for Mars Atmosphere and Volatile Evolution, which is a $671 million mission set to discover why Mars has no atmosphere, how exactly it was lost and when. MAVEN was launched in November 2013 and reached Mars' orbit in September 2014. "Scientists will use MAVEN data to determine the role that loss of volatiles from the Mars atmosphere to space has played through time, giving insight into the history of Mars' atmosphere and climate, liquid water, and planetary habitability," wrote NASA officials on the mission overview of the MAVEN spacecraft. MAVEN is just one of the five spacecraft in Mars' orbit. Others include NASA's Mars Reconnaissance Orbiter and Mars Odyssey, European Space Agency's Mars Express and India's Mangalyaan probe. Is there definite proof that Mars can be the next Earth? In September 2015, NASA confirmed that "liquid water flows intermittently on present-day Mars" based on data provided by the space agency's Mars Reconnaissance Orbiter (MRO). There were also speculations that ancient Mars once had huge oceans and river systems but scientists believe a catastrophic event 'wiped out' these bodies of water. Today, Mars' surface and skies seem barren and incapable of supporting any form of life, however, theories hold that it once had the right environments for the development of life.
Kopp G.,Laboratory for Atmospheric and Space Physics |
Lean J.L.,U.S. Navy
Geophysical Research Letters | Year: 2011
The most accurate value of total solar irradiance during the 2008 solar minimum period is 1360.8± 0.5 W m-2 according to measurements from the Total Irradiance Monitor (TIM) on NASA's Solar Radiation and Climate Experiment (SORCE) and a series of new radiometric laboratory tests. This value is significantly lower than the canonical value of 1365.4± 1.3 W m -2 established in the 1990s, which energy balance calculations and climate models currently use. Scattered light is a primary cause of the higher irradiance values measured by the earlier generation of solar radiometers in which the precision aperture defining the measured solar beam is located behind a larger, view-limiting aperture. In the TIM, the opposite order of these apertures precludes this spurious signal by limiting the light entering the instrument. We assess the accuracy and stability of irradiance measurements made since 1978 and the implications of instrument uncertainties and instabilities for climate research in comparison with the new TIM data. TIM's lower solar irradiance value is not a change in the Sun's output, whose variations it detects with stability comparable or superior to prior measurements; instead, its significance is in advancing the capability of monitoring solar irradiance variations on climate-relevant time scales and in improving estimates of Earth energy balance, which the Sun initiates. Copyright 2011 by the American Geophysical Union.
News Article | November 6, 2015
The first astronauts to set foot on Mars may be in for a spectacular sight — the entire night sky filled with glowing auroras. Researchers working on NASA's Mars Atmosphere and Volatile Evolution (MAVEN) mission hosted a news conference this afternoon (Nov. 5) to discuss the orbiter's observations about the Red Planet's loss of atmosphere due to solar wind, and they also shared some details about MAVEN's measurements of Mars auroras. "A new kind of aurora was observed at Mars that frankly surprised us, and this was aurorae in a part of the atmosphere that is above regions that don't have a magnetic field at all," Dave Brain, MAVEN co-investigator and researcher at the University of Colorado Boulder's Laboratory for Atmospheric and Space Physics (LASP), said during the news conference.
The NASA-funded MinXSS CubeSat will launch December 2015 to study soft X-rays from the sun. There have not yet been long-term studies of these soft X-rays, but observations show they may be important clues to understanding what heats the sun's atmosphere to 1,000 times the temperature of its surface. Credit: NASA/CU On Dec. 4, the bread loaf-sized Miniature X-Ray Solar Spectrometer, or MinXSS, CubeSat is scheduled to rocket to space alongside thousands of pounds of supplies and science experiments destined for the International Space Station. MinXSS will study the spectroscopy of soft x-rays, a particular type of light from the sun. This light is highly variable and can impact Earth's upper atmosphere, which can in turn affect communications such as GPS and radio. CubeSats are a low-cost alternative to traditional satellite missions. Instead of carrying a dozen or more custom-built instruments, CubeSats are designed to take specific scientific observations with only a few instruments, often built from off-the-shelf components. MinXSS, for example, is using an extendable tape measure as a radio antenna and a standard, off-the-shelf, laboratory x-ray spectrometer. MinXSS is a project of the University of Colorado Boulder, and the Laboratory for Atmospheric and Space Physics. Because of their lower price tags, universities run many CubeSat missions from start to finish, providing opportunities for students to take part in all parts of a mission. "I've worked on nearly every aspect of MinXSS," said James Mason, a graduate student studying aerospace engineering at the University of Colorado Boulder. "Students can get involved with everything on a CubeSat mission—systems engineering, management, manufacturing, and even on-orbit science analysis." The MinXSS CubeSat will study the sun's impact on Earth's upper atmosphere by measuring the variability of the intensity and spectrum of soft X-rays emitted by the sun. The sun always emits some amount of soft x-rays, but the intensity of these emissions can increase by a factor of thousands during events on the sun called flares. The interaction of soft X-rays with the Earth's upper atmosphere can hamper communications by changing the atmospheric region called the ionosphere, effecting how communications signals travel through this region. MinXSS will hitch a ride to space aboard Orbital ATK's Cygnus cargo spacecraft, which is scheduled to launch on a United Launch Alliance Atlas V rocket Dec. 4, 2015, at 5:33 pm EST. Once delivered to the ISS, the MinXSS CubeSat will deploy into space in January 2016 and operate for up to 12 months. Explore further: Almost anyone can hitchhike into space with a nanosatellite
The fantasy creations of the Star Wars universe are strikingly similar to real planets in our own Milky Way galaxy. A super Earth in deep freeze? Think ice-planet "Hoth." And that distant world with double sunsets can't help but summon thoughts of sandy "Tatooine." No indications of life have yet been detected on any of the nearly 2,000 scientifically confirmed exoplanets, so we don't know if any of them are inhabited by Wookiees or mynocks, or play host to exotic alien bar scenes (or even bacteria, for that matter). Still, a quick spin around the real exoplanet universe offers tantalizing similarities to several Star Wars counterparts. The most recently revealed exoplanet possessing Earth-like properties, Kepler-452b, might make a good stand-in for Coruscant — the high-tech world seen in several Star Wars films whose surface is encased in a single, globe-spanning city. Kepler-452b belongs to a star system 1.5 billion years older than Earth's. That would give any technologically adept species more than a billion-year jump ahead of us. The denizens of Coruscant not only have an entirely engineered planetary surface, but an engineered climate as well. On Kepler-452b, conditions are growing markedly warmer as its star's energy output increases, a symptom of advanced age. If this planet (which is 1.6 times the size of Earth) were truly Earth-like, and if technological life forms were present, some climate engineering might be needed there as well. Mining the atmospheres of giant gas planets is a staple of science fiction. NASA, too, has examined the question, and found that gases such as helium-3 and hydrogen could be extracted from the atmospheres of Uranus and Neptune. Gas giants of all stripes populate the real exoplanet universe; in The Empire Strikes Back, a gas giant called Bespin is home to a "Cloud City" actively involved in atmospheric mining. The toadstool-shaped city provides apparent refuge for a fleeing Princess Leia and company — at least until Darth Vader wreaks his usual havoc. Many of the gas giants found so far by instruments, such as NASA's Kepler Space Telescope, are so-called "hot Jupiters" — star-hugging behemoths far too thoroughly barbecued to be proper sites for floating cities. One recent discovery, however, shows that gas "exogiants" can orbit their stars at distances remarkably similar to those in our solar system. An international astronomical team discovered a twin of our own Jupiter, orbiting its star at about the same distance as Jupiter is from the sun. The star, HIP 11915, is about the same age and composition as our sun, raising the possibility that its entire planetary system might be similar to ours. This not-so-hot Jupiter, about 186 light-years away from Earth, was detected using the 11.8-foot (3.6-meter) telescope at La Silla Observatory in Chile. Bespin's atmospheric layers include a band of breathable air, ideal for floating cities. In our galaxy, emerging technology allows us to read out the components of real exoplanet atmospheres — including gas giants (though so far none show signs of habitable layers). And tasting the atmospheres of smaller, rocky, potentially habitable exoplanets soon could be within reach. Astronomers using K2, the second planet-finding mission of the Kepler space telescope, recently detected three such planets orbiting a nearby dwarf star. The starlight shining through the atmospheres of these planets could reveal their composition in future observations. The planet Mustafar, scene of an epic duel between Obi-Wan Kenobi and Anakin Skywalker in Revenge of the Sith, has a number of exoplanet counterparts. These molten, lava-covered worlds, such as Kepler-10b and Kepler-78b, are rocky planets in Earth's size range whose surfaces could well be perpetual infernos. Kepler-78b, roughly 20 percent larger than Earth, weighs in at twice Earth's mass; a comparable density means it could be composed of rock and iron. That might make it, like Mustafar, suitable for mining, although its extremely tight orbit around its sun-like star, along with scorching temperatures, provides an unlikely arena for industrial operations — or for fencing with lightsabers. Kepler-10b isn't much more pleasant. The first rocky world discovered using the Kepler telescope, it also hugs its sun, some 20 times closer than Mercury orbits ours. A balmy day on Kepler-10b means daytime highs of more than 2,500 Fahrenheit (1,371 Celsius), even hotter than lava flowing on Earth. The surface, free of any kind of atmosphere, might be boiling with iron and silicates. At 3,600 degrees Fahrenheit (1,982 Celsius), however, CoRoT-7b has Kepler-10b beat. This well-grilled planet, discovered in 2010 with France's CoRoT satellite, lies some 480 light-years away, and has a diameter 70 percent larger than Earth's, with nearly five times the mass. Possibly the boiled-down remnant of a Saturn-sized planet, its orbit is so tight that its star looms much larger in its sky than our sun appears to us, keeping its sun-facing surface molten. The planet OGLE-2005-BLG-390, nicknamed "Hoth," is a cold super-Earth that might be a failed Jupiter. Unable to grow large enough, it had to settle for a mass five times that of Earth and a surface locked in the deepest of deep freezes, with a surface temperature estimated at minus 364 degrees Fahrenheit (minus 220 Celsius). That most likely means no "Hoth"-style tauntauns to ride, or even formidably fanged abominable snowmen (aka "wampas"). Astronomers used an extraordinary planet-finding technique known as microlensing to find this world in 2005, one of the early demonstrations of this technique's ability to reveal exoplanets. In microlensing, backlight from a distant star is used to reveal planets around a star closer to us. The planet lies toward the heart of the Milky Way, where a greater density of stars makes microlensing events more likely. The one-time event revealing the distant Hoth was captured by the Optical Gravitational Lensing Experiment, or OGLE, and confirmed by other instruments. We won't have to travel 20,000 light years, however, to visit icy worlds. Saturn's smoggy moon, Titan, where the Cassini spacecraft's Huygens probe landed in 2005, is pocked with methane lakes and socked in permanently with thick, hydrocarbon haze. The freeze is so deep that water ice is no different from rock. Another Saturn moon, Enceladus, looks like a snowball but harbors a subsurface ocean much like Jupiter's moon Europa, another ice ball with a likely ocean underneath. That ocean would be warmed by tidal flexing as the little moon orbits Jupiter. Luke Skywalker's home planet, Tatooine, is said to possess a harsh, desert environment, swept by sandstorms as it roasts under the glare of twin suns. Real exoplanets in the thrall of two or more suns are even harsher. Kepler-16b was the Kepler telescope's first discovery of a planet in a "circumbinary" orbit — circling both stars, as opposed to just one, in a double-star system. This planet, however, is likely cold, about the size of Saturn, and gaseous, though partly composed of rock. It lies outside its two stars' "habitable zone," where liquid water could exist. And its stars are cooler than our sun, and probably render the planet lifeless. Of course, we could look on the bright side (so to speak). When the discovery was announced in 2011, Bill Borucki, the now-retired NASA principal investigator for Kepler at Ames Research Center, Moffett Field, CA, said finding the new planet might actually broaden the prospects for life in our galaxy. About half of all stars belong to binary systems, so the fact that planets form around these, as well as around single stars, can only increase the odds. A more recently announced exoplanet, Kepler-453b, is also a circumbinary and a gas giant, though its orbit within its star's habitable zone means any moons it might have could be hospitable to life. It was the tenth circumbinary planet discovered using the Kepler telescope. Kepler-22b, analog to the Star Wars planet Kamino (birthplace of the army of clone soldiers), is a super-Earth that could be covered in a super ocean. Watery, storm-drenched Kamino makes its appearance in Attack of the Clones. The jury is still out on Kepler-22b's true nature; at 2.4 times Earth's radius, it might even be gaseous. But if the ocean world idea turns out to be right, we can envision a physically plausible Kamino-like planet, with the help of scientists at the Massachusetts Institute of Technology in Cambridge. An ocean world tipped on its side — a bit like our solar system's ice giant, Uranus — turns out to be comfortably habitable based on recent computer modeling. Researchers found that an exoplanet in Earth's size range, at a comparable distance from its sun and covered in water, could have an average surface temperature of about 60 degrees Fahrenheit (15.5 degrees Celsius). Because of its radical tilt, its north and south poles would be alternately bathed in sunlight and darkness, for half a year each, as the planet circled its star. Scientists previously thought such a planet would seesaw between boiling and freezing, rendering it uninhabitable. But the MIT scientists' three-dimensional model showed that the planet, even with a relatively shallow ocean of about 160 feet (50 meters), would absorb heat during its odd polar summer and release it in winter. That would keep the overall climate mild and spring-like year round. The shallow depth, by the way, would be ideal for Kamino-style ocean platforms, allowing construction of covered cities at the ocean surface, where armies of clones could march and drill in peace. Fly me to the exomoon Endor, the forested realm of the Ewoks, orbits a gas giant and was introduced in Return of the Jedi. Detection of exomoons — that is, moons circling distant planets — is still in its infancy for scientists here on Earth. A possible exomoon was observed in 2014 via microlensing. It will remain forever unconfirmed, however, since each microlensing event can be seen only once. If the exomoon is real, it orbits a rogue planet, unattached to a star and wandering freely through space. The planet might have hung on to its moon after somehow being ejected during the early history of a forgotten planetary system. A team of Japanese, New Zealand, and American astronomers analyzed data gathered in 2011 with telescopes in New Zealand and Tasmania, and suggested the possible exomoon. They said a small star accompanied by a large planet also could have caused the same lensing effect. More exomoons might soon be popping out from the depths of space. The Harvard-based Hunt for Exomoons with Kepler, or HEK, has begun to scour data from Kepler for signs of them. In early 2015, the researchers examined about 60 Kepler planets and determined that existing technology is sufficient to capture evidence of exomoons. The hunt could have powerful implications in the search for life beyond Earth. If exomoons are shown to be potentially habitable, it would open another avenue for biology; habitable moons might even outnumber habitable planets. Could they have bustling ecosystems, with life forms even more exotic than Endor's living teddy bears, swinging between trees Tarzan-style? Stay tuned. Breaking up is hard to do In A New Hope, Princess Leia’s home planet, Alderaan, is blown to smithereens by the Empire’s Death Star as she watches in horror. Real exoplanets also can experience extreme destruction. A white dwarf star was caught in the act of devouring the last bits of a small planet in 2015, observed with the help of NASA's Chandra X-ray Observatory. White dwarfs are super-dense stellar remnants about the size of Earth, but with gravity more than 10,000 times that of our sun's surface. Tidal forces could rip a planet caught in its pull to shreds. Observers thought at first they were seeing a black hole in the act of feeding inside a star cluster on the Milky Way's rim. X-ray observations, however, matched theoretical models of a planet being torn apart by a white dwarf. A similar observation of a closer white dwarf was made by K2 in 2014. In this case, a tiny rocky object, probably an asteroid, was being vaporized into little more than a dusty ring as it whipped around the star every 4.5 hours. NASA's Spitzer Space Telescope also picked up signs of debris from a likely asteroid collision in 2014. But rather than a sign of planetary destruction, the colliding asteroids could be part of a construction site. This young star — about 1,200 light years away and only 35 million years old — is surrounded by a ring of dust where such collisions are frequent. The smashed and broken bits fuse into larger and larger agglomerations, eventually forming full-sized planets. Our own solar system might once have looked very similar, if anyone was watching. NASA's Ames Research Center in Moffett Field, CA, manages the Kepler and K2 missions for NASA's Science Mission Directorate. NASA's Jet Propulsion Laboratory in Pasadena, CA, managed Kepler mission development. Ball Aerospace & Technologies operates the flight system with support from the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder. JPL, a division of the California Institute of Technology in Pasadena, manages the Spitzer Space Telescope for NASA.