This is the Dudley Observatory Skywatch Line for Wednesday, October 28th, and Thursday, October 29th, written by Louis Suarato.
The 93% illuminated, waxing gibbous Moon rises at 5:05 p.m. Wednesday. Mars rises 4 minutes later and will trail the Moon by about 10 degrees throughout the night. Thursday night, Mars will lead the Moon across the sky. The Moon and red planet will be separated by about 5 degrees. Jupiter and Saturn emerge over the southern horizon 6 degrees apart during twilight. The two gas giants will set at 10:28 p.m., and 10:55 p.m., respectively. Venus rises at 4:22 a.m., about 3 hours before sunrise.
On October 28, 1991, Galileo became the first spacecraft to approach an asteroid. Galileo flew by the asteroid Gaspra on its way to Jupiter. Gaspra was discovered by Russian astronaut G.N. Neujmin in 1916. Gaspra is a 3.1 by 4.3 mile asteroid that completes its orbit around the Sun once every 3.29 years. Its orbit takes Gaspra beyond Mars to the asteroid belt, approximately 2.21astronomical units, or 205.53 million miles. Since then, 16 asteroids have been visited by space probes. The most recent mission to an asteroid occurred last week when the spacecraft OSIRIS-Rex (Origins, Spectral Interpretation, Resource Identification, Security Regolith Explorer) landed on asteroid 101955 Bennu and obtained samples. After traveling over 200 million miles in four years, OSIRIS-Rex collected a sample of about 60 grams from the asteroid’s surface. The sample will be returned to Earth in September 2023. Asteroid Bennu was chosen for this mission because it is composed of carbon rich materials carrying the building blocks of planets and life and may shed light as to how the solar system was formed. Bennu orbits the Sun once every 1.2 years, coming as close as 300,000 miles to Earth.