New Theory of Moon Origin

A study of the zinc contents of lunar rock samples brought back to the Earth by the Apollo astronauts strongly suggests that the Moon formed not from the crust of a Mars sized planet striking the young Earth, but from the debris field formed by the collision of the two planets.  You can read about it here.

Advertisements

Jump From the Edge of Space

Felix Baumgartner made history today, jumping from about 128,000 feet, an altitude of over 24 miles.  Preliminary estimates indicate that he resoundingly broke the speed of sound in air barrier, traveling at a maximum speed of Mach 1.24, or 834 mph.  Keep in mind that the speed of sound in air number he needed to exceed is a function of the temperature and density of the  thin atmosphere he was travelling through.  The speed of sound in air at the Earth’s surface is about 768 mph.

It was a great deal of fun and somewhat nerve wracking as I, and upwards of 7.3 million other viewers on various livestreams, watched his descent, in optical and infrared frequencies.

I Luv Vi Hart

Perhaps you heard of the blog phenom named Vi Hart, who posts mathematically intriguing videos about geometric shapes, number theory and the like.  It’s always a hands-on experience for sure, but she often includes references to historical figures, such as Blaise Pascal, or in the case of the following video, Richard Feynman.

You can see the first part of her video summary of hexaflexagons here.

Breaking the Sound Barrier, With Your Head

Felix Baumgartner is making his final preparations for a record-breaking, supersonic skydive from a little less than 23 miles above New Mexico’s desert surface.  The jump is currently scheduled for Tuesday, October 9th.

Reports are that he will be going directly to Disneyworld after landing.

Shine On Harvest Moon

Folks of a certain age (which includes yours truly) grew up singing “Shine On Harvest Moon” along with Mitch Miller and his bouncing ball.  On You Tube, a wonderful and humorous version of this song is sung by none other than Oliver Hardy, with Stan Laurel soft shoeing in accompaniment.

More to the science of it, the Harvest Moon is defined as the moon closest to the autumnal equinox.  This moon just occurred the night of September 30th, and was captured, by a Chicago Tribune photographer, framing the statue on the top of the old Montgomery Ward’s administration building.  As a child, my dad comically deceived us into thinking the statue was that of a monkey, hence “Monkey Wards”.

My understanding of the Harvest Moon is that it was used by farmers to extend their harvest past sundown.  In any event, the moon lies low to the horizon, and so looks large, because of the moon illusion.  Further, the moon looks yellowish and gauzy, because it shines more directly through the atmosphere of the eastern horizon.

Why is the Harvest Moon so low in the sky when it rises?  The answer is that the Moon and the Sun both track the ecliptic, and thus the full moon is “two seasons advanced” in angular declination relative to the current location of the Sun.  Since the Sun is shining over the equator on the autumnal equinox, the full moon will have a corresponding zero declination over the eastern horizon at sunset (6 PM standard time).

I hope you enjoy the You Tube video as much as I did.  Click on the picture to learn how it was taken.