Double planets like to Earth in size, which revolve around each other, there may be near distant stars, the researchers say. Most of the planets in our system have their own satellites. Our neighbors such as Saturn and Jupiter, for example, have more than seventy satellites.
Without looking at it, these satellites are generally much smaller than their planet – Earth almost four times bigger than its satellite, and more than eighty times heavier.
However, there are also satellites whose dimensions are comparable to the size of other planets. For example, Ganymede, the largest moon of Jupiter, more than Mercury, and is three-quarters the diameter of Mars.
Furthermore, in our own system, the satellites have similar in size to the size of their own planets. Pluto’s largest moon, Charon, is about half the diameter of its dwarf host. As a result, there is an interesting question whether the planet in the universe exists, having the same size, which would have turned around one another.
Binary stars – stars rotate next to each other, quite familiar with our Milky Way. Most of these binary systems are known to even exist exoplanets, which may be called the worlds with two suns. Also in our solar system known binary asteroids. Nevertheless, the existence, double planets whose size could be compared with the earth, is now found only in science fiction assumptions.
One of the possible ways to form a double planet may be the case when two planets orbiting the star at some point in its existence, closer to a distant enough for their gravitational interaction.
To make sure that such systems are possible, the researchers, with the help of a computer program, modeled two rocky objects the size of Earth, located on a little distance on the space standards. In their paper, the researchers changed the weight, speed and trajectory of convergence of the planets. As a result, scientists have created about two dozen models.
Without looking at it, these models often lead to a impact of planets, whereby they are connected turning into one large-size planet. Sometimes after a impact near the new planet formed from material ejected disc into orbit from which then formed the satellite. We also obtain a model in which the planets moving after the collision at high speed, received minor injuries and just flew in differing directions, and sometimes even have been thrown out of their star system.
Nonetheless, approximately one third of all models failed to receive the double planets. In these models, the planet approached rather slowly and avoid collisions.
These double planets orbit close sufficiently to one another, they are removed only by a distance corresponding to about half the diameter of the planets. Over time, the speed of rotation around its axis is aligned at both planets. As a result of this level, one planet always looks for another one and the same side.
These binary systems can survive for many billions of years, the researchers say, if they are located at a expanse of at least 0.4 AU from its star at a distance because gravity stars will not disrupt their interaction.