Bob Moler's Ephemeris Blog

Monday, September 27th.*  The sun will rise at 7:35.  It’ll be up for 11 hours and 55 minutes, setting at 7:30.   The moon, 3 days before last quarter, will rise at 9:16 this evening.

Astronomers have been discovering planets around other stars for the last 15 years.  These planets tend to be as massive as Jupiter or greater, and tend to be very close to their parent stars.  The orbital period of these planets tend to be the matter of days.  Over the years we had been comfortable with how the planets are located in our solar system:  Inner rocky worlds and farther out large gaseous planets.  Now, what we are finding is in part the result of the techniques we use, which are most sensitive to large planets orbiting close to their stars.  Currently aloft is a spacecraft called Kepler that we hope is also sensitive to small planets orbiting farther from their stars by recording them passing in front of their stars.

*Times are for the Grand Traverse Area of Northern Michigan, USA.