This week I downloaded an application called Exoplanets onto my iPhone. Not only does it have a list of confirmed extra-solar planets (some 825 and counting in the database), but it also has the ability to plot the discoveries in terms of mass, density, distance, semi-major axis, and many other variables. My favourite feature, however, is the button that reads “Milky Way”.
When you press this button, you are brought to a map of the Milky Way. This is no regular map though; it’s the most amazing map I’ve used in a long time. It’s cooler than Google Earth. And I think we’ve all spent hours zooming around in Google Earth. By using one finger and dragging, you can rotate the galaxy, and pinching with two fingers will zoom in. By tapping a star once you can centre the map there, and tapping twice takes you on a whirlwind journey closer and closer to the star until you can see the planet(s) orbiting it.
The stars with exoplanets are coloured red and they are the only ones the app allows you to focus on. I find it interesting (although it totally makes sense) that the vast majority of red dots lie in the area around the Sun. Nearby stars appear much brighter and so they will be much easier to analyze for Doppler Shifts and for transits.
Another neat feature of this map is that the Earth’s constellations are drawn in the sky with white lines connecting the stars. When you zoom in to our Solar System, all of the shapes are recognizable. There is the Big Dipper, Orion, Cygnus, etc. When you zoom in to another star somewhat near the Sun, say HD 33654a, the stars that make up our constellations are still connected, but the shapes are totally different. This reminds me how arbitrary our constellations are. Not only can you draw most any shape from the bright stars in the sky, no two stars share the same sky; any shapes drawn on the night sky will be unique to the planet that draws them.