It’s a commonly heard complaint for would-be urban star-gazers: with the amount of light pollution in a big metropolitan area, especially one the size of Chicago, it’s impossible to see any stars. While it is true that most stars get overwhelmed by the amount of light that is in an average night sky here in the city, it might be surprising to find out that it can often be much easier for a beginning urban astronomer to find cosmological objects in the sky. Why? If you’ve ever looked up while out in the country, you probably noticed that there are a LOT of stars out there. In fact, there are so many that even if you use a star chart, it might be harder for a beginner to find even iconic constellations like the Big Dipper. In Chicago, though, the light pollution only allows the brightest stars to shine, making constellations fairly easy to find. You don’t even need a telescope to see some really interesting objects.
This month, Venus is a very prominent object high in the southwestern sky. If you’re on the NEIU campus, all you have to do is look above the Library after twilight. The planet will most likely be the brightest object in the sky besides the moon, but wait a moment to make sure it’s not an incoming airplane. When you’re sure it’s not moving, pat yourself on the back. You’ve just found the second planet from the sun!
Venus was named after the Roman goddess of love, though conditions on the planet are anything but lovely. At one time it was thought to be Earth’s ‘twin,’ and some early scientists even proposed the idea that there could be life on it. They didn’t know it at the time, but Venus is a very unlikely place to look for life. As it turns out, Venus is the hottest planet in the Solar System with temperatures nearly reaching 900 degrees Fahrenheit. This is because Venus has something called the ‘runaway greenhouse effect’ – like Earth, Venus also has problems with carbon emissions. Although the planet doesn’t have to worry about cars or factories, Venus is covered in hundreds of active volcanoes, which spew sulfur and carbon dioxide into the atmosphere, trapping heat and making Venus absolutely unlivable. It’s an important reminder of how greenhouse gases can get out of control, and something to keep in mind about how things could turn out here on Earth.
Another prominent object is the constellation Orion, which rises in the south. If you’re on the NEIU campus, the best place to search for it would be in between the PE complex and the Library where you will have a clearer view of the southern sky. Look for its iconic ‘belt’ of three stars in a diagonal. Above and to the left of the belt, you might notice a really bright star, which forms Orion’s right shoulder. This is Betelgeuse (don’t be worried about the spelling – it’s pronounced the same as Michael Keaton’s Beetle Juice movie), which is a red supergiant star. That means that if it was right where our sun is, it would be so large that its surface would stretch out nearly to Jupiter’s orbit, swallowing up Mercury, Venus, Earth and Mars. Needless to say, it’s a REALLY big star.
On top of being rather large, red supergiants also have short lives (only a few million years) and have a tendency to end their lives by exploding in an event called a supernova. Despite being about 600 million light years away from us, when Betelgeuse ‘goes supernova’, it could possibly be an even brighter object in the night sky than the moon. Actually, Betelgeuse could have already gone supernova, but because it is so far away from us, light from the star takes 600 million years to reach us. It is an interesting thought to leave you all with – when you look up into the night sky, you are looking at light that has taken millions of years to reach you. So in effect, you are looking into the past.
For extra help locating other constellations, you can print up this free star chart to get started: http://content.telescope.com/rsc/img/catalog/lc/starcharts/02Feb09StarChart_clr.pdf