The Earth has four seasons—spring, summer, fall, and winter. Do other planets in the solar system have seasons? Before answering that question, let’s review what causes the Earth’s seasons.
This spring will bring us the best view of Mars in seven years.
The “comet of the century” died before its time.
In August I introduced you to comet ISON. In the last two months we have learned much more about the comet.
About every 175 years the orbits of the outer planets — Jupiter, Saturn, Uranus and Neptune — are arranged so that a spacecraft on a particular flight path can swing from one planet to the next without the need for large onboard propulsion systems.
During the formation of our solar system — in the outer regions where it is cold enough to permit ices of water, methane, ammonia and carbon dioxide to exist — the comets were born.
Every year in mid-August the Earth intersects the orbit of the Swift-Tuttle comet. Lewis Swift and Horace Tuttle independently discovered this comet in 1862.
There are many objects in the sky you can see with your unaided eyes, but these are only a small fraction of the objects you can see if you use a telescope.
Saturn during April and May was the closest, biggest and brightest it will be during 2013. And it will still be a great view in June.
Since the beginning of recorded history, people who have looked at the night sky have tried to understand and predict the motions of the stars.