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Astronomy for Kids
The First Seven Astronauts
Everything starts somewhere, and the space program began in earnest with the selection of the first seven astronauts that would participate in manned space flight. The NASA selection committee was made up of Charles Donlan, a senior management engineer; Warren North, a test pilot engineer; Stanley White and William Argerson, flight surgeons; Allen Gamble and Robert Voas, psychologists; and George Ruff and Edwin Levy, psychiatrists.
When the selection committee began their task, they received 508 applications. This number was reduced to 110 candidates after records were reviewed. The 110 candidates were brought together at an undisclosed location. A battery of tests were given and interviews were conducted. It took a month but the number of possible candidates was reduced to 32.
The 32 candidates were then subjected to even more stressful physical, psychological, and mental examinations. They were given full-body x-rays, tested in pressure suits, endured a variety of cognitive tests and really intense interviews. Finally, 18 or the 32 were recommended to the Mercury program without any medical reservations.
The final choices were made by Robert Gilruth, who was the head of the Space Task Group, as well as Charles Donlan, Warren North, and Stanley White.
The first seven astronauts selected for the Mercury program (the first manned space flight program) were Scott Carpenter, L. Gordon Cooper Jr., John H. Glenn Jr., Virgil I. "Gus" Grissom, Walter M. Schirra Jr., Alan B. Shepard Jr., and Donald K. "Deke" Slayton. Their names will resound through history forever.
Six of the original seven flew in Project Mercury. Only "Deke" Slayton did not fly because of a heart condition that had not been discovered. Deke later flew as a crewmember of the Apollo-Soyuz Test Project.
See Also:
Space Future
Astronomy for Kids
The Planet Venus
Back in 1686, a French scholar by the name of Bernard de Fontenelle, wrote, "I can tell from here...what the inhabitants of Venus are like; they resemble the Moors of Granada; a small black people, burned by the sun, full of wit and fire, always in love, writing verse, fond of music, arranging festivals, dances, and tournaments every day."
Nice try, Bernard, but you had it all wrong. Back in those days, it was generally accepted that Venus was much like Earth. Venus is about the size of Earth, but that's pretty much where all resemblance ends.
Almost all of the planets in our solar system travel around the sun in a counterclockwise direction…all of them except Venus and Uranus, that is. Venus (as well as Uranus) travels clockwise. All of the planets except Venus and Uranus rotate on their axis in a counterclockwise direction. Venus and Uranus rotate clockwise.
Venus also rotates really slowly, too. A "day" on Venus would equal about 243 Earth days. Venus is covered by a thick layer of clouds that make studying the surface very difficult. In the last 30 years, however, astronomers have learned how to "see" through the thick cloud cover.
In 1962, Mariner 2 was the first spacecraft to go by Venus. Since then, there have been 20 more missions. The first hard landing on Venus was done by Venera 4 in 1967. The first soft landing was done by Venera 7 in 1970.
In 1989, the Magellan spacecraft probe was launched. Magellan rotated around Venus from 1990 to 1995. It then burned up in the atmosphere of Venus. Magellan bounced radar signals off the surface of Venus and transmitted the data back to Earth. |
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Solar Eclipses
Our Sun's Twin
Jorge Melendez of the Australian National University, and Ivan Ramirez of the University of Texas at Austin, are both astronomers from Peru. Using the Harlan J. Smith Telescope at McDonald Observatory located atop Mount Locke and Mount Fowlkes in the Davis Mountains of West Texas, they discovered the best candidate as a twin to our sun that has been found to date in November 2007. The findings by Melendez and Ramirez suggest that our sun's chemical composition is not unique, as some previously thought.
The star found by the Peruvian astronomers is in the constellation Draco, which is over 200 light years away from our solar system. HIP 56948, the star in question is more like our sun than any yet seen. The star may be a billion years older than the sun.
There have been three other possible twins to our sun located, but there is a major difference in the amount of lithium they contained. These stars -- 18 Scorpius, HD 98618, and HIP 100963 -- have all been contenders, but they all contain several times more lithium than our sun. This difference has led astronomers to believe that our sun was possibly unique because of its low amount of lithium. Now, it seems, maybe our sun is not so unique after all.
The search for solar twins to our sun is important because astronomers use our sun as a baseline for a variety of astronomical studies, and studying our own sun is very difficult because it is too close and too bright.
The discovery of HIP 56948 by Melendez and Ramirez lays to rest the belief that our sun is somehow completely unique and that the uniqueness is what allowed life to spring up and thrive and raises the possibility (no, probability) that life exists in other places in the universe. Maybe we aren't alone.
Related Topics: Our Solar System,
Telescope Accessories, The Future of Space Travel
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