Asteroid Near Earth Discovered by Amateur Astronomers (SPACE.com)

A team of amateur astronomers has discovered a previously unknown asteroid in orbit that brings it near the Earth, highlighting the contributions regular folks can make to planetary defense, scientists announced Wednesday (Oct. 12).

The skywatchers spotted the asteroid, which is known as 2011 SF108, in September using a telescope in the Canary Islands. While 2011 SF108's orbit appears to bring it no closer to Earth than about 18 million miles (30 million kilometers), it still qualifies as a near-Earth object — the class of space rocks that could pose a danger to our planet.

The team took advantage of an observation slot sponsored by the European Space Agency's Space Situational Awareness (SSA) program to make the find, according to an ESA announcement.

"As volunteer work, it is very rewarding," said Detlef Koschny, head of near-Earth object activity for SSA, in a statement. "When you do spot something, you contribute to Europe's efforts in defending against asteroid hazards." [Photo of newfound asteroid 2011 SF108]

Amateurs make a find

Asteroid 2011 SF108 was discovered by the Teide Observatory Tenerife Asteroid Survey (TOTAS) team, a group of 20 skywatching volunteers. They used the 1-meter telescope at the European Space Agency's Optical Ground Station on Tenerife in the Canary Islands.

Specifics on the asteroid's estimated size were not detailed in the ESA announcement.

The telescope observed for four nights, running automated asteroid surveys using software developed by amateur astronomer and computer scientist Matthias Busch from the Starkenburg Amateur Observatory in Heppenheim, Germany.

Busch's software flags potential space rocks, but the finds must be confirmed by human eyes. The software scored a hit during the observing session of Sept. 28 and 29, researchers said.

"Images are distributed to the entire team for review, and any one of them could be the discoverer of a new asteroid," Koschny said. "This time, the luck of the draw fell to Rainer Kracht."

Kracht, a retired schoolteacher who lives in Elmshorn, Germany, is therefore 2011 SF108's official discoverer. He now has found 46 asteroids, researchers said.

To date, about 8,000 near-Earth objects have been discovered worldwide, but many thousands more are suspected to exist. Astronomers are keen to find as many of them as possible, so they can better assess the chance that a big, dangerous space rock will slam into Earth sometime soon.

Since starting their SSA-sponsored survey work in January 2010, the TOTAS amateur astronomers have identified nearly 400 candidate asteroids, 20 of which have been confirmed and named, researchers said.

Determing the orbit

After examing telescope images from three separate nights, the TOTAS team was able to determine 2011 SF108's orbit well enough to declare it a near-Earth object.

The team sent news of its find to the Minor Planet Center in Cambridge, Mass., the worldwide clearinghouse of information about comets and asteroids.

While 2011 SF108 appears not to pose much risk to Earth for the foreseeable future, further observations could help refine its orbit and our assessment of just how dangerous it might be, researchers said. But for now, the team can bask in the glow of discovery for a spell.

"It was really an exciting moment when I saw 'our' asteroid appearing on my computer screen," Koschny said. "It confirms the excellent quality of work done by the entire TOTAS team."

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Did an Amateur Astronomer Spot a Secret Mars Base? (SPACE.com)

A self-described "armchair astronaut" claims to have identified a human (or alien) base on Mars. David Martines noticed a mysterious rectangular structure that appears to be on the Red Planet's surface while trolling the planetary surface using Google Mars, a new map program created from compiled satellite images of the planet.

"This is a video of something I discovered on Google Mars quite by accident," said Martines, the armchair astronaut, in a now-viral YouTube video. "I call it Bio Station Alpha, because I'm just assuming that something lives in it or has lived in it."

He zooms in the surface anomaly — a long, pixelated, white object — and lists the coordinates as 49'19.73"N 29 33'06.53"W. "It's over 700 feet long and 150 feet wide. It looks like it's a cylinder or made up of cylinders," he says.

Has Martines really found evidence of alien life, or a secret space base, as he and some media sources are claiming? No, say experts: "Bio Station Alpha" is simply a glitch in the image caused by cosmic energy interfering with the camera.

"It looks like a linear streak artifact produced by a cosmic ray," said Alfred McEwen, a planetary geologist at the Lunar and Planetary Lab at the University of Arizona and the director of the Planetary Imaging Research Laboratory. McEwen is the principal investigator of the High Resolution Imaging Science Experiment (HiRISE), a powerful telescope currently orbiting Mars.

Cosmic rays are extremely energetic particles emitted by the sun and other stars. For the most part, the Earth's protective magnetosphere blocks them from hitting the planet's surface, McEwen explained. "But with space images that are taken outside our magnetosphere, such as those taken by orbiting telescopes, it's very common to see these cosmic ray hits. You see them on optical images and a lot of the infrared images too," he told Life's Little Mysteries. [Read: Why Do Photos from Deep Space Take So Long to Get to Earth?]

As a cosmic ray passes through a camera's image sensor, it deposits a large amount of its electric charge in the pixels that it penetrates. If the particle passes through at a shallow angle to the plane of the camera, it affects several pixels along its path. The result is a bright streak on the image.

The digital compression software that converts the image into a JPEG file then "sort of smears out the image, giving it that pixelated look," McEwen said. What started as a clear streak in high-resolution turns into a streak that, in the armchair astronaut's words, looks like it is "made up of cylinders."

McEwen said that the cosmic ray streak would be much easier to recognize in the raw, pre-compressed image, but many orbiters and telescopes have contributed imagery to create the Mars map, and Google doesn't identify the source image.

"I can't tell whether this image was taken by Viking or what," McEwen said. "The people at Google need to document what the heck they're doing. They should be able to identify what the source of their information is, and let people know so they can go back and look at the raw data."

This story was provided by Life's Little Mysteries, a sister site of SPACE.com. Follow Natalie Wolchover on Twitter @nattyover.

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