2020 probably wasn't anybody's favorite year. But there was a lot to celebrate of astronomical interest. It was so hard to choose a top ten, some similar events were grouped together. Asteroids, the Moon, Mars and the Sun all feature, and there were two splendid skywatching events.
Arachnophobes needn't worry about this tarantula. It's not a big spider, it's a big nebula that looks a bit like a spider in some photos. It's also so far away that its light takes 170,000 years to get here. Stars are born there, stars die there, and it's a spectacular object.
No one alive had seen Venus transit when the 2004 one occurred. And if you missed that and the 2012 transit, there isn't another until 2117. However Mercury also transits the Sun – and these transits happen more often. But what's a transit and what do we learn from it?
The starter's pistol for the space race was fired on October 4, 1957. It was in the form of a small highly-polished sphere that orbited the Earth every 98 minutes. This was the Soviet Union's Sputnik, Earth's first artificial satellite. It shook up the United States, and there was more to come.
Most of our knowledge of Neptune and Uranus is based on Voyager 2's visits. Its grand tour of the four giant planets used a rare alignment of the planets that let the gravity of each one boost the spacecraft to the next one. No other probe has been to either of the ice giants.
Rosetta, the European Space Agency (ESA) spacecraft, traveled for ten years and billions of miles in order to rendezvous with a comet, accompany it as it moved through the inner Solar System past the Sun, and deploy a lander.