Bob Moler's Ephemeris Blog

Ephemeris for Thursday, April 5th.  The sun will rise at 7:15.  It’ll be up for 13 hours exactly, setting at 8:15.   The moon, 1 day before full, will set at 6:44 tomorrow morning.

Astronomers have come to the realization that what we see in the universe as normal matter is only four percent of the universe’s mass and energy.  Dark matter makes up about 23 percent, while the totally mysterious dark energy makes up the rest.  We do have some clues about what dark matter is.  We still can’t see it.  However we can detect its presence in distant galaxy clusters.  Since whatever it is has mass, it can distort space-time, and the path of light that passes through it.  We can detect it because it distorts the shapes of more distant galaxies we see through it.  The amount and shape of the distortions point to the location and densest of the dark matter.  Whatever this stuff is it has mass, and has and is affected by gravity, but apparently doesn’t interact with ordinary matter of itself for that matter.

* Times are for the Traverse City/Interlochen area of Michigan.  They may be different for your location.