The recently launched Lucy mission will take on the task of exploring Jupiter's Trojan asteroids, leading to a new understanding of these strange objects. While waiting for the spacecraft to reach its first targets, today's close-up of some of the asteroids of all shapes and sizes already visited or studied from Earth.
Discovered by Giuseppe Piazzi in 1801 , Ceres is the largest object in the asteroid belt, between Mars and Jupiter. Considered a dwarf planet since the first passage of the American probe Dawn, in 2015, this object is of interest to the scientific community. And for good reason, according to a series of studies recently published, Ceres would be "an oceanic world" with liquid and salty water flowing under its surface.
Incidentally, we also recall that a Finnish researcher proposes to create a human colony in orbit around the object. According to him, this option would be a more viable alternative to Martian colonization.
Apollinian asteroid 2014 JO25 is a very irregularly shaped space rock that spins around once every 4.5 hours or so. The object was observed closely in April 2017 by the Arecibo observatory, destroyed a few months ago following several cable breaks, while the object was triggered just over a million kilometers from Earth.
With an average diameter of about 530 kilometers, Vesta is the second largest object in the asteroid belt after Ceres. Several of its fragments have already hit Earth as meteorites. The object also offers a very shiny surface sometimes visible to the naked eye from Earth depending on light pollution conditions.
Eros was the first near-Earth asteroid to be discovered after an accidental appearance on a photographic plate in 1898 . It was also the first asteroid to be imaged by a spacecraft in orbit (NEAR in 1998), a century after its discovery. This same ship also landed on Eros in 2001. It was then the first "human landing" on an asteroid.
Bennu recently made headlines thanks to the OSIRIS-REx mission which is currently returning to Earth with samples from the asteroid. The return capsule should land in 2023 . These chunks of rock and dust are sure to reveal new clues about the history of our Solar System, and possibly the origin of life on Earth.
Let's end with Ida, the first asteroid known to have its own moon (named Dactyl, visible on the right). It is believed to be debris from an ancient collision between two larger objects. You will find them in the main belt, between the orbits of Mars and Jupiter.
