Are the discovered asteroids the remains of the planet Theia that collided with the Earth, lifted its crust into space, from which the moon was formed * Stereo spacecraft will try to search with the help of Internet surfers
NASA's twin Stereo spacecraft are now entering a mysterious region of space to search for the remains of an ancient planet that once orbited the Sun not far from Earth's orbit. If they find something, it may solve a big puzzle - the origin of the moon.
"The planet's name is Theia," says Mike Kaiser, a scientist with the Styro project at NASA's Goddard Space Center. "This is a hypothetical world that we have never seen, but some of the researchers believe that it existed 4.5 billion years ago - and it is the one that collided with the Earth and created the Moon.
The Thalia hypothesis is the brainchild of Princeton theorists Edward Bellabruno and Richard Gott. It begins with the popular theory about the origin of the moon. Many astronomers occur in the years of the formation of the solar system. A planet the size of Mars collided with Earth. Debris from the crash, a mixture of materials from both bodies, reassembled in space to form the moon. The script explains many aspects of lunar geology, including the size of the lunar core and the density of the isotope composition in the lunar rocks. It's a good theory, but it leaves one question unsolved: Where did that big protoplanet come from? Belbruno and Gott believe that it came from Lagrange points between the sun and the earth.
As we described in a previous article, there are five such points that serve as a common gravitational well for the Sun and the Earth. When the solar system was young, Lagrange points were populated mainly by planetesimals - building blocks of planets, which are the size of asteroids. Bellabruno and Gott suggest that at one of these Lagrange points L4 and L5, the planetesimals at Yenham merged to form Theia, named after the Titan from Greek mythology who gave birth to the moon goddess Selen.
Their computer models showed that Taia could have been large enough to form the Moon if it formed in the L4 or L5 regions, where the balance of forces allowed enough material to accumulate, Kaiser says. "Later, Theia was ejected from the region where it was formed due to the increase in the gravitational force of other developing planets such as Venus, and this gravitational disturbance sent that planet on a collision course with Earth.
If the theory is correct, Theia itself is long gone but some ancient planetesimals that did not join Theia may still be found in L4 or L5. "Stereo spacecraft are entering this region of space now," Kaiser said. "This puts us in a good position to look for those asteroids left over from Aia. We will simply call them thysteroids"
Astronomers have looked for asteroids in the past using telescopes from Earth and found nothing, but with the method you can observe, you can only see objects a kilometer or more in size. Only by entering L4 L-5 respectively, stereo spacecraft can be in the best position to see much smaller objects from a relatively short range.
"The search actually began about a month ago when the two spacecraft turned 180 degrees so that they could take two-hour exposures of the general area. In the first series of images, amateur astronomers found several familiar asteroids and a new comet - Itagaki just a few days after the announcement of the discovery. However, the remains of the thiasteroids were not found."
According to Kaiser, the hunt for the thiasteroids is not Stirao's main mission. "Stirao is a solar observatory, the two spacecraft examine the sun on opposite sides so that we can get a three-dimensional view of the sun's activity. It just happened that they had to pass through points L4 and L5 on their way, it's just a scientific bonus."
"It is very possible that we will not see anything," he added, "but if we discover many asteroids near L4 or L5 this may lead to a mission that will analyze the composition of these asteroids in detail. If this mission reveals that asteroids have a composition similar to that of the Earth or the Moon, this will support the Bellabruno and Gott version of the big impact theory.”
The search will last many months. Lagrange points are not small points in space. These are vast areas with a diameter of 50 million kilometers. Stereo spaceships are at the edge of these areas. It will make a close approach to the bottom of the gravity well in September-October 2009. "We have many observations ahead of us," said Kaiser.
The Stirao team invites the public to participate in the research by scanning the images when they arrive from the spacecraft. They are seen by someone as moving points relative to the stars, it is possible that these are thyasteroids. the instructions are at the address This.