00:14As well as stars, galaxies and quasars, Gaia also observes objects in our solar system,
00:21measuring their positions and brightnesses at different times.
00:26By far the largest group of solar system objects in Gaia's data release 3 are 154,741 asteroids,
00:37for which Gaia has determined the orbits.
00:39Depending on their orbits, one can distinguish different groups of asteroids.
00:44Most of the asteroids are in the main belt between the orbits of Mars and Jupiter.
00:50Over a period of about 10,000 years, Jupiter's powerful gravity can perturb an asteroid's path so strongly that some
00:59of them become Mars crossers.
01:01Do you notice another group that is around the distance of Jupiter?
01:06They are the so-called Trojans.
01:08They are collected in two clusters, preceding and following the giant planet, but never getting close to it.
01:14If we move beyond the orbit of Neptune, we find trans-Neptunian objects.
01:20Gaia observed the brightest 24 members of this population.
01:30Let's now focus again on the internal regions of the solar system.
01:38Back in the inner solar system, we find objects that come close to the Earth and sometimes cross its orbit.
01:44They were brought to the inner solar system from the main belt due to gravitational perturbations by Jupiter and other
01:50planets.
01:51Due to close encounters with the terrestrial planets, the orbits of near-Earth asteroids reach large inclinations with respect to
01:58the Earth's orbit
01:59and can also come very close to the Sun, where they experience strong heating.
02:04None of the known near-Earth objects is a danger to Earth in the coming decades, but it is very
02:10important to determine their orbits precisely.
02:13We now move close to the Earth and observe this group of 446 near-Earth asteroids.
02:22Finally, we move into the main belt and see many of the 153,220 asteroids passing by.
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