When we see the Earth’s only Moon up in the sky, we often think about how small it is. It’s only about 1/4 the diameter of the Earth, and at a distance of 384,000 Km, it looks small in the sky. But often size is entirely a matter of perspective. What we compare something to, that’s what determines it’s size. When the Moon is high in the sky we easily compare it to the size of the window we are looking through, or to a nearby tree, or our outstretched hand. All of this can make the Moon seem pretty tiny....
Some days at work, when I am in the Space hall at the Ontario Science Center, I take a close look at the golf-ball-sized Moon rock we have on display. I think about how this rock was brought back on an Apollo mission over 40 years ago, how it had been an untouched part of the Moon for Billions of years before this, and how it has taught us so much about how the Moon, and subsequently the Earth, formed. But now it’s time for a new generation of Moon rocks to be analyzed, and China is in the nation...
Lovely Earth is not entirely lonely. We have five planets that have been observed since the dawn of civilization. The five are visible with the naked eye in the sky at different times of year, and were given the name planets as a derivation of the Greek ‘planetes,’ meaning ‘wanderers.’ They do wander, or at least they appear to move against the background of the stars, since they are much closer to the Earth as it orbits the Sun. So what planets are visible this month? For September 2015 and back to school, you had better be willing to get...
Our Solar System is so much more than just the eight planets that inhabit it. One of the things I learned a bit later in my career as an astronomer (my teenage years; been doing this for awhile) is how unique and diverse the natural satellites are. Our own moon seems somewhat tame, and it’s easy to think the same of all moons. Many of them are boring quiescent rocks with little more scientific value than asteroids, but the largest hide deep and profound secrets that we are just starting to unlock. Four moons in our solar system are larger...
