On the morning of Sunday December 9, The brightest asteroid Vesta will be in opposition to the Sun, close to the bright planet Jupiter. CREDIT: Starry Night Software
On Sunday (Dec. 2), the giant planet Jupiter reached opposition with the sun, lining up directly opposite the sun in the sky. That means it's a great target for stargazers, who can see it shine brightly all night long this week.
Within the next two weeks, two more solar system bodies will also reach opposition right alongside Jupiter:Vesta and Ceres.
Seven years ago, these would be described as the solar system's two largest asteroids, which are a large group of small bodies whose orbits mostly lie between the orbits of But in 2006, the International Astronomical Union, the governing body of astronomy, reclassified Ceres as a dwarf planet, grouping it together with Pluto and other Kuiper Belt objects. Many astronomers still classify Ceres as an asteroid, even though at 592 miles (952 kilometers) in diameter, it is almost twice as large as the next largest asteroids, Pallas (326 miles, or 524 km), and Vesta (319 miles, or 513 km.). It is also round in shape, while most asteroids are irregular potato shapes.
The two charts below are snapshots of the same area of sky as it will appear on Dec. 9 and Dec. 18. All the background stars are the same in both views, but the three solar system bodies, Jupiter, Vesta, and Ceres, all jump slightly to the right between the two views.