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Scientists find a solar-powered asteroid
March 08, 2007An international research team led by Academy Research Fellow Mikko Kaasalainen has found an asteroid whose rotation receives an extra kick from solar radiation. The asteroid 1862 Apollo's diameter is about 1.5 km, it has a small moonlet, and its orbit crosses that of the Earth. The team reconstructed Apollo's shape and determined its rotational state using brightness measurements from several years. They found that Apollo's rotation speed steadily increases, and showed that this is due to the re-radiation of solar energy from its surface. The study was published in Nature online on 7 March.
Apollo's rotation period is slightly over three hours, and it decreases only by four thousandths of a second per year, so the analysis required accurate mathematical methods. Because of the acceleration, Apollo is likely to break apart or radically change its figure in the future. It may already have done so earlier, and its present moonlet may be a remnant of such a breakup.
The study confirms that non-gravitational forces are important in the dynamical evolution of asteroids. Re-radiation of solar energy acts as a propulsion engine on the asteroid's surface. There are two coupled manifestations of this phenomenon: the one changing the orbit (the Yarkovsky effect), and the one changing the spin state (the Yarkovsky-Radzievskii-O'Keefe-Paddack or YORP effect). The study confirmed the latter, and the former was detected by radar in 2003. Non-gravitational orbital and spin changes can be significant or even critical over long time intervals. They affect the motion of asteroids that may collide with the Earth. The phenomenon can also be used to estimate the masses of asteroids. Apollo is now the first object larger than one kilometre across for which the propulsion effect has been detected.
Academy of Finland
Academy of Finland
Asteroid News and Current Asteroid Events RSSCosmic connections: Imperial scientist locates the origin of cosmic dust
The research, published in the journal Geology, shows that some of the cosmic dust falling to Earth comes from an ancient asteroid belt between Jupiter and Mars. This research improves our knowledge of the solar system, and could provide a new and inexpensive method for understanding space.
Tunguska catastrophe: Evidence of acid rain supports meteorite theory
The Tunguska event is regarded as one of the biggest natural disasters of modern times. On 30 June 1908 one or more explosions took place in the area close to the Tunguska River north of Lake Baikal. The explosion(s) flattened around 80 million trees over an area of more than 2000 square kilometres.
Discovery of the source of the most common meteorites
When observing with the GEMINI telescopes, two astronomers from Brazil and the United States discovered for the first time asteroids that are similar to "ordinary chondrites", the most common meteorites found on Earth. Until now, astronomers have failed to identify their asteroidal sources because of the various geologic processes that occur after the meteorites are ejected from their asteroidal parent body.
The Mystery of Mass Extinctions Is No Longer Murky
If you are curious about Earth's periodic mass extinction events such as the sudden demise of the dinosaurs 65 million years ago, you might consider crashing asteroids and sky-darkening super volcanoes as culprits.
Ebb and flow of the sea drives world's big extinction events
If you are curious about Earth's periodic mass extinction events such as the sudden demise of the dinosaurs 65 million years ago, you might consider crashing asteroids and sky-darkening super volcanoes as culprits.
Plutoid chosen as name for Solar System objects like Pluto
Almost two years after the International Astronomical Union (IAU) General Assembly introduced the category of dwarf planets, the IAU, as promised, has decided on a name for transneptunian dwarf planets similar to Pluto.
Engineering researcher seeks answers to asteroid deflection
An Asteroid Deflection Research Center (ADRC) has been established on the Iowa State campus to bring researchers from around the world to develop asteroid deflection technologies. The center was signed into effect in April by the Office of the Executive Vice President and Provost.
65-million-year-old asteroid impact triggered a global hail of carbon beads
The asteroid presumed to have wiped out the dinosaurs struck the Earth with such force that carbon deep in the Earth's crust liquefied, rocketed skyward, and formed tiny airborne beads that blanketed the planet.
UMd-led team finds ancient asteroids formed at solar system's start
Using visible and infrared data collected from telescopes on Hawaii's Mauna Kea, a team of scientists, led by the University of Maryland's Jessica Sunshine, have identified three asteroids that appear to be among our Solar System's oldest objects.
Meteorites a rich source for primordial soup
The organic soup that spawned life on Earth may have gotten generous helpings from outer space, according to a new study. Scientists at the Carnegie Institution have discovered concentrations of amino acids in two meteorites that are more than ten times higher than levels previously measured in other similar meteorites.
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