The Harvest Moon is coming up on Friday the 14th and all across the country people think they know what it means. Some assume it has no observational significance and that "Harvest Moon" is just another archaic name like April's "Grass moon." Others imagine just the opposite, that the Harvest Moon looks special in some way: bigger or redder or higher or - something.
Now that it's September, we've all noticed that daylight is shrinking. Meteorologists often recite the number of hours and minutes of sunshine each day and then say "It's a decrease of two minutes from yesterday." Yet tomorrow they might say there's only one minute of decrease, or a three minute decrease. Let's get to the bottom of this.
This week it's the birthday of 127 million people from around the world, making our planet's shared birthdays pretty common. If we take one complete revolution around the sun to constitute a birthday, then our planet has had 4.5 billion birthdays.
The vast majority of meteors strike our atmosphere at between 22 and 37 miles per second, but thankfully our atmosphere slows nearly all meteors. Meteroids weighing more than 10 tons are were things get dangerous because they retain a portion of their original space velocity and could hit the ground at 10,000 miles per hour.
The Perseid meteor shower is ruined by a nearly full moon. The moon has once been long a scapegoat for many other problems too, but recent studies allow us to replace those old myths with new lunar powers.
So far this summer, we've had humid days as well as drier ones. What most people don't know is that meteorologists express humidity with the word 'dewpoint.' At night, high humidity gives us a sky without many stars that don't twinkle.
On this week's episode Bob Berman explains why a dark night is important for health, and how gorgeous phenomena only materialize when there is no artifical skyglow, something most of us living in urban environments don't get to experience.