PHOTO (courtesy NASA)-39 years ago this month, the Lunar Module of Apollo 11 made the first manned landing on the Moon. Shortly after being the first man to step on the Moon, Neil Armstrong made this photo of his crewmate, Buzz Aldrin stepping on the lunar surface. In 2020, NASA plans to return humans to the Moon with the Ares rocket carrying the new Orion spacecraft, now under construction.

Beginning this blog, I will also post the monthly column, America in Space, that I send to about 70 newspapers and appears in the Piggott Times print edition. Feel free to comment or ask any questions. I also answer questions on space travel and astronomy, as well as on music (conducting) and time management on the national website, www.allexperts.com.

America in Space-July 2008 by Kenneth Renshaw, NASA/JPL Solar System Ambassador, Piggott, Arkansas

METEORITE ANNIVERSARY, RECENT NASA MISSIONS

Late on the evening of June 29, US time (7:17 AM Russian time, June 30) was the 100th anniversary of what was probably the most massive meteorite strike in recent history. That morning in Siberia, Russia, near the Tunguska River, what was probably a comet or asteroid (it is still debated what really happened) exploded about 28 thousand feet above the ground, striking the atmosphere at about 33,500 miles per hour, creating a temperature at that altitude of 44,500 degrees Fahrenheit. The comet or asteroid was probably about 120 feet in diameter, and detonated with the power of 185 Hiroshima atomic bombs. Trees were leveled for dozens of miles, with the trees at ground zero actually standing with their limbs stripped, with no crater and little recoverable debris (indicating a high-altitude explosion). This was similar to the scenario in 1945 when Hiroshima was actually bombed. Although this size strike only occurs once every few hundred years, no one can guarantee it won't occur tomorrow. Astronomers are working on identifying all hazardous projectiles in space, although none of the hundreds of earth-crossers found currently have our name on it for the near future. Every several million years, a truly gigantic asteroid strikes Earth, about 5-10 miles across, causing mass extinctions. One hit about 65 million years ago on the Yuchitan Peninsula (Mexico), possibly spelling the end of the dinosaurs. A much smaller 1-Hiroshima one hits the Earth's atmosphere about every year without causing damage or fatalities, being at a high altitude. The 1908 Tunguska strike resulted in few, if any human fatalities, but a modern strike over the US would kill millions.

Meteorites also strike the Moon and other planets, sometime knocking rocks and soil from these objects into space. Lunar and Martian rocks from these blasts have been confirmed to eventually hit the Earth. I have in my possession small samples of meteorites that have been chemically confirmed to have originated on the Moon and Mars. If you are in the NE Arkansas area, they are currently on loan at the Matilda Pfeiffer Museum in Piggott, Arkansas for public viewing, along with a sample of the historic 1930 Paragould, Arkansas meteorite fall (820 lbs.).

A more modern anniversary in space history occurred this month. 39 years ago July 20, man first landed and walked on the Moon, when the lunar module of Apollo 11 landed on the lunar surface. Seven years later, on the same date, the first unmanned Viking lander successfully touched down on Mars--July 20, 1976.

Now, for a quick overview of the space and astronomy news for this month: