Showing posts with label Earth. Show all posts
Showing posts with label Earth. Show all posts

Tuesday, November 23, 2010

Small Asteroid to Give Earth a Close Shave

This story was updated at 4:32 p.m. ET.

A tiny asteroid will zip close by Earth tonight (Nov. 16) at a range much closer than the moon, but poses no threat of striking our planet or even entering the atmosphere, NASA has announced.

The asteroid 2010 WA will pass Earth at 10:44 p.m. EST (0344 GMT), missing the planet by about 24,000 miles (38,000 kilometers), NASA's asteroid-watching team wrote on Twitter. It is nearly 10 feet (3 meters wide), so small it would simply break apart if it encountered Earth's atmosphere.

NASA officials said the asteroid is a "very small space rock" that will pass the Earth at roughly one-tenth the distance between our planet and the moon, according to NASA's AsteroidWatch Twitter feed. [5 Reasons to Care About Asteroids]

On average, the moon is about roughly 238,900 miles (384,402 km) from Earth. Some of the highest satellites above Earth fly in geostationary positions about 22,370 miles (36,000 km) up. The International Space Station sails through space about 220 miles (354 km) above Earth.

Asteroid 2010 WA is the fourth space rock in as many months to buzz harmlessly by the Earth within the moon's orbit. The asteroid 2010 TD54 passed the planet at nearly the same miss distance on Oct. 12. In September, a rare sighting of two asteroids ? called 2010 RX30 and 2010 RF12 ? was spotted when they both passed within the moon's orbit on the same day (Sept. 8).

Like 2010 WA, those earlier asteroid flybys posed no threat to Earth and most were small enough that they would burn up in the atmosphere if they hit it.

"Still, a good practice in detection," NASA's asteroid-tracking team wrote of 2010 WA on Twitter.

An asteroid about 16.5 feet (5 meters) across can be expected to pass Earth inside the orbit of the moon about once a day, NASA scientists have said. They typically enter Earth's atmosphere about once every two years, they added.

Bigger asteroids of about 460 feet (140 meters) wide can cause widespread damage around their impact sites. But much larger space rocks would have to strike Earth to cause global devastation.

There are an estimated 30 million unknown asteroids in our solar system, NASA has said.

Asteroid 2010 WA is not even the first space rock to slip by the Earth-moon system this month.

On Nov. 9, the small asteroid 2010 VL65 passed the Earth at a range of 610,000 miles (980,000 km) ? about 2 1/2 times the distance between our planet and moon, NASA officials said. That asteroid was only 23 feet (7 meters) across ? small enough to burn up completely in the atmosphere ? and was only visible to seasoned skywatchers with telescopes.

NASA routinely tracks asteroids and comets that fly near Earth as part of its Near-Earth Object Observations program, which uses a network of ground and space telescopes to monitor the space rock environment around the planet. To date, the program has tracked about 85 percent of the largest asteroids that fly near Earth and 15 percent of asteroids in the 460-foot class, according to the latest report.

The U.S. space agency also plans to send astronauts to an asteroid by 2025 under a space plan ordered by President Obama. The mission could help scientists better understand the composition of asteroids, as well as develop better methods of deflecting them before they pose a threat to Earth, agency officials have said.


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Wednesday, November 17, 2010

Journeys into the Hollow Earth

North Pole entrance.


This diagram shows how an entrance to a hollow planet might look.



• In 1824, a wealthy doctor is said to have mounted an expedition to find Symmes' Hole at the south pole, but the journey was unsuccessful.


• In 1893, Dr. Fridtjof Nansen designed his own ship, the Fram, to explore the north pole. Hollow earth followers have cited his reports of warm winds coming from the north, of red and green pollen covering the snow in some areas, and of fresh driftwood found in the Arctic Ocean ice, where there are no trees. All of these anomalies, hollow Earthers say, have come out of the warm northern opening.


• In 1926, Admiral Richard E. Byrd became the first person to fly over the North Pole. In 1929, he successfully flew over the South Pole. Although officially, of course, Byrd discovered no entrances into the Earth's interior at either pole (he certainly wasn't looking for any), staunch hollow Earthers contend that he really did find a hole at the North Pole. They say he may have even flown as far as 4,000 miles into the interior, although there's no evidence to support this.


• In 1939, the Americans and Germans were in a race to explore and claim lands in Antarctica. President Roosevelt sent Admiral Byrd to the frozen continent to thwart any German claims to Antarctic lands in the Western Hemisphere. Hollow Earthers have proclaimed that this was actually a secret mission to beat the Nazis in the exploration of "the land beyond the poles."


• In 1947, Admiral Byrd is said to have made a secret flight to the North Pole to find this land beyond the pole. The "evidence" for this flight comes from a highly controversial "lost diary" kept by Byrd and miraculously found in the 1970s by "The Society for a Complete Earth." In it he writes that as he looked down from his plane, he saw not snow, but green vegetation, grassy valleys and mountains not shown on any map. Very few take this diary - or the flight itself - seriously.