In addition to the planets, there are many chunks of rock (asteroids) in orbit around the earth. The impact of a large asteroid with Earth 65 million years ago is believed to have caused a earth-wide disaster that killed the dinosaurs and allowed mammals to spread over the earth. In fact, the possibility of an impact of a large asteroid with Earth has caused great concern among politicians and scientists, and one of the functions of the WISE project is to scan the skies for asteroids and comets. Comets are different than asteroids and are believed to be chunks of ice and dirt that orbit the sun. As comets near the sun, their ice vaporizes and leaves the long tail that is characteristic of comets.
Scientists are actively investigating asteroids and comets. Here are some of their results.
An important discovery has been made concerning the possible inventory of molecules available to the early Earth. Scientists led by Sandra Pizzarello, a research professor in ASU's Department of Chemistry and Biochemistry, found that the Sutter's Mill meteorite, which exploded in a blazing fireball over California last year, contains organic molecules not previously found in any meteorites. These findings suggest a far greater availability of extraterrestrial organic molecules than previously thought possible, an inventory that could indeed have been important in molecular evolution and life itself.
Lawrence Livermore scientist Nir Goldman and University of Ontario Institute of Technology colleague Isaac Tamblyn (a former LLNL postdoc) found that icy comets that crashed into Earth millions of years ago could have produced life building organic compounds, including the building blocks of proteins and nucleobases pairs of DNA and RNA.
The water found on the moon, like that on Earth, came from small meteorites called carbonaceous chondrites in the first 100 million years or so after the solar system formed, researchers from Brown and Case Western Reserve universities and Carnegie Institution of Washington have found.
A new look at conditions after a Manhattan-sized asteroid slammed into a region of Mexico in the dinosaur days indicates the event could have triggered a global firestorm that would have burned every twig, bush and tree on Earth and led to the extinction of 80 percent of all Earth's species, says a new University of Colorado Boulder study.
NASA and international researchers have discovered that Earth's moon has more in common than previously thought with large asteroids roaming our solar system.
Chemists from the University of California, Berkeley, and the University of Hawaii, Manoa, showed that conditions in space are capable of creating complex dipeptides -- linked pairs of amino acids -- that are essential building blocks shared by all living things. The discovery opens the door to the possibility that these molecules were brought to Earth aboard a comet or possibly meteorites, catalyzing the formation of proteins (polypeptides), enzymes and even more complex molecules, such as sugars, that are necessary for life.
The small near-Earth asteroid 2012 DA14 will pass very close to Earth on February 15, so close that it will pass inside the ring of geosynchronous weather and communications satellites. NASA's Near-Earth Object Program Office can accurately predict the asteroid's path with the observations obtained, and it is therefore known that there is no chance that the asteroid might be on a collision course with Earth. Nevertheless, the flyby will provide a unique opportunity for researchers to study a near-Earth object up close.
The duo then studied observations of the 520 giant planets found outside our solar system. Only 19 of them reside outside the snow line, suggesting that most of the giant planets that may have formed outside the snowline have migrated too far inward to preserve the kind of slightly-dispersed asteroid belt needed to foster enhanced evolution of life on an Earth-like planet near the belt. Apparently, less than four percent of the observed systems may actually harbor such a compact asteroid belt.