Daniel Pope

As we gaze around the night sky at this time of year we cannot help but notice in the northeast the third brightest star above the northern hemisphere, Vega (VAY-gah or VEE-gah). The main reason it looks so bright is that it’s relatively nearby as stars go, only 25 light years away. Vega is about twice as hot as our Sun, more than twice as big across, and 50 times more luminous. Vega serves as another signpost in my never-ending quest of – where am I and where am I going? As our Sun and Solar System revolve around the center of our Milky Way galaxy we are moving in the general direction of Vega. This region of the sky is now coming under very close scrutiny by the Kepler Space Telescope.

Johannes Kepler (1571-1630) is credited with providing the first complete and accurate mathematical model of the movements of the planets in our Solar System. It does seem appropriate that the mission to specifically look for Earth-like planets in other solar systems is named in his honor. The Kepler Telescope was launched on March 6, 2009. It saw “first light” on April 8 and all elements are functioning as expected. Kepler will be examining 100 square degrees of sky between Lyra and Cygnus. Your fist at arm’s length will about cover the area. There are over 4,000,000 stars in that field of view. For at least the next 3 1/2 years Kepler will be staring at 100,000 of those stars looking for telltale signs of planets. These stars are between a few hundred and a few thousand light years away from us. For comparison: our Milky Way galaxy has over 200,000,000,000 stars, is about 100,000 light years in diameter and we are about 26,000 light years from its center. It is expected that by early 2010 Kepler will be finding large planets and smaller ones later on. This is a significant sample size and by 2012-2013 we will have a large amount of data that will statistically show whether or not we can expect to find many Earth-like planets when we consider our entire Milky Way galaxy.

Brilliant Vega anchors the small and dim but beautiful constellation, Lyra (LYE-rah), the Lyre. The darker the sky and the later you stay out, the better your chances of seeing all of Lyra. Your closed fist at arm’s length will more than cover the whole constellation. Look below or east of Vega for a small parallelogram of four stars as depicted in the graphic. Now look for another star just a little north or to the lower left of Vega. Use this star to form a small triangle with Vega and the top star in the parallelogram. The triangle and parallelogram form the exquisite shape of Lyra. If you have a dark sky look carefully at the star to the lower left (north) of Vega. Some people can see that this is a double star with their naked eye. Everyone else can experience this “double” with binoculars. This is actually known as the famous “double-double” in Lyra. “Double-double” meaning that a telescope reveals that each of the naked eye or binocular doubles is yet another double.

Perhaps you have seen pictures from the Hubble Space Telescope of the Ring Nebula or M57. It is not a naked eye object but I like knowing where it is in our sky. It is about half way between the two stars that form the southern end of the parallelogram of Lyra. In a telescope it appears as a small hazy smoke ring. The Ring Nebula is the result of a dying star. The star has used up a great deal of its mass in its fusion reaction and that has led to a collapse that has produced the cloud of gas that forms the ring.

If your eastern horizon is quite dark you might be able to detect the misty band of our Milky Way somewhat parallel to eastern horizon just below Lyra. If you can see it, you are looking at the main disk of our home galaxy, the Milky Way, edge-on from within our galaxy itself – cool! Here again, having a moonless night really helps.

From the Greek stories we learn that the lyre, the first stringed musical instrument, was invented by Hermes, the messenger of the Olympian gods. Hermes traded the lyre to Apollo, the Sun god, for a magical staff. Apollo gave the lyre to his son, Orpheus, who became the greatest master of this instrument.

When Jason was assembling his crew of Argonauts, the Centaur, Chiron, told him he would need Orpheus and his lyre. The Argo would have to sail by the Sirenum scopuli islands, where the Sirens, sea nymphs, would sing their enchanting songs and attract the crew to their deaths on the rocks. As Jason and the Argonauts approached and the Sirens began to sing, Orpheus played even more entrancing music on his lyre, drowning out the Sirens, thus saving the Argo and her crew.

Next week we will locate Scorpius, the Scropion, and discuss its part of our night sky.

Clear Skies