October 23, 2017

Review: Falling to Earth by Al Worden and Francis French.

Out from Smithsonian Press!

We’re approaching 40 years since the last human set foot on the Moon, and we’ve yet to have the ability to point at a calendar and state unequivocally when such a feat may happen again. Thus, the era is dwindling when we can hear the stories of these early astronauts, in their own words. This week’s review entitled Falling to Earth tells the tale of NASA astronaut Al Worden, the Command Module pilot for Apollo 15. [Read more...]

02.04.11: Stalking an Impact.

Click image to see animation…(Credit: Stefano Sposetti/Marco Iten/Geological Lunar Researches Group).

Take a look at the image above. It may not be one of the most colorful we’ve ever run, but it shows something dramatic; a possible impact on the limb of the Moon. On February 11 of this year, Stefano Sposetti and Marco Iten of Gnosca Observatory Switzerland used a Borg 125 ED refractor and a high speed video camera along with a similar setup attached to a Celestron 11 at a separate location to record the flash on the nighttime side of the then just past 1st Quarter Moon. [Read more...]

26.03.10: Dude, That’s My Rover!

The Apollo 13 booster impact site. (Credit: NASA/GSFC?Arizona State University).
Apollo XIII booster impact site. (Credit: NASA/GFSC/Arizona State University).

 

   Attention, lunar landing deniers; NASAs Lunar Reconnaissance Orbiter has a bone to pick with you. The LRO continues to reveal some fairly mind-blowing pics of the Moon up-close. This week saw two uber-cool images which show what a littered place the lunar surface has become. First up is the splat of the Apollo 13 upper stage north of the Mare Cognitum pictured above. Apollo 13 was, of course, the “successful failure” of Hollywood lore. Bright rays and ejecta are apparent, and you can almost picture the booster tail sticking straight out of the lunar regolith like some bad Beastie Boys album cover. Sensors placed 135 km distant by Apollo 12 astronauts registered the impact event.   [Read more...]

Astro Event: The Closest Full Moon of the Year.

Last year's Wolf Moon as seen from Astroguyz HQ in Hudson, Florida. (Photo by author).

Last year's Wolf Moon as seen from Astroguyz HQ in Hudson, Florida. (Photo by author).

(Editor’s note: Due to a flurry of astronomical events, February’s events of the week will be released on an accelerated schedule; hang on!)

Amid the opposition of Mars, two launches out of the KSC and the Cape next week, and an exceptionally fine elongation of Mercury in the early morning skies, this weekend brings us a special treat; the closest Full Moon of the year. This Moon, known also as the Full Wolf Moon, is technically full at precisely 06:00 Universal time on Saturday morning, the 30th of January. This comes only 3 hours prior to perigee, when the Moon is closest to Earth in its orbit. At this time, the Moon will be only 217,862 miles distant, and appear 34.1’ arc minutes in size, as opposed to 29.3’ arc minutes at apogee. An added plus is that this Full Moon occurs at a very northerly declination in the constellation Cancer, and hence will be riding high for northern hemisphere viewers all night. And don’t forget ruddy Mars, just 7° degrees north of the Moon!

The astro word for this week is albedo. Think that bright silvery Full Moon is bright? Science says otherwise. Albedo is the measure of the percentage of light reflected back by an astronomical object; 100% is a full mirror, optimal reflection, and 0% is pitch black. On Earth, fresh snow reflects about 85% of the light that falls on it, and the average albedo of Earth is about 30%, depending on the amount of cloud cover and the percentage of land versus ocean presented to the Sun. In fact, this phenomenon of reflectivity may play a key role in a lesser known effect impacting global climate; that of global dimming. Now for the real shocker; the average albedo for the Moon is about 10%, slightly less than worn asphalt! Ask the Apollo astronauts; the Moon is in fact, a very grey-to-black place! The reason that this weekend’s Full Moon looks bright is that you are seeing the sum of 5% of the Sun’s reflected light crammed into an area tinier than a fingernail at arm’s length. In fact, anyone who has stood under a 99% percent eclipsed Sun, as occurred earlier this month, will tell you that even 1% of the sun’s output is still pretty bright!