Animation of 2012 LZ1 compiled from 10-second exposures with a 78" telescope June 13.

Amateur astronomers with 10-inch or larger telescopes can watch newly discovered near-Earth asteroid 2012 LZ1 slowly crawl from northern Sagittarius into southern Aquila tonight. Although it’s on the larger side – between 984 to 2,300 feet across – LZ1 will be faint because it won’t pass as close as several other notable Earth approachers have this year.

Minimum distance from Earth occurs early this evening around 8 p.m. CDT when the giant rock will be 3.4 million miles away or about 14 times the distance of the moon. Thanks to Ernesto Guido, Nick Howes and Giovanni Sostero we can watch it stroll across the sky (left).

LZ1 will shine meekly at 14th magnitude (very faint) and move about 20 arc minutes or 2/3 the width of the full moon an hour to the northeast. That’s quick it enough to notice its movement over several minutes time through a telescope. If you have clouds tonight, the asteroid will be out again tomorrow night June 15 and appear only slightly fainter.

To plot its position, please stop by JPL’s Horizons website, select your city and click the Generate Ephemeris link. You’ll be taken to a table of Universal times (Remember to subtract 4 hours for EDT, 5 for CDT and so on) and positions which you can plot on a detailed sky chart. You can also grab 2012 LZ1′s orbital elements to plunk into your own sky charting program by going HERE and typing the name into the search box.

One idea for deflecting potentially dangerous asteroids uses "mirror bees", small satellites equipped with mirrors that focus sunlight on the asteroid to vaporize rocks and create thrust. Credit: The Planetary Society

While this asteroid poses no threat to our planet, some day, whether this year or 100,000 years from now, astronomers will discover a significant space rock on a collision course with Earth. You’ve probably heard of ideas on how we might deflect or destroy such an object before it becomes our nemesis. These range from using nuclear bombs to blast it to bits to landing a type of rocket thruster on its surface that would continuously fire, slowly changing the body’s orbit. We might also send a swarm of small satellites equipped with mirrors to focus sunlight and vaporize rocks on the asteroid’s surface. The gas created would drive the body out of harm’s way.

A U.S. military scientist operates a powerful blue laser in a lab. Click photo to learn how lasers work.

In a new twist, two researchers at University of
Strathclyde in Scotland suggest we deploy solar-powered lasers. Similar to sunlight, the lasers would cook rock into streams of hot vapor, pushing the asteroid off course and hopefully saving the planet.  The advantage of lasers vs. sunlight is that the satellites could do their beaming from a much greater distance, avoiding getting cameras and sensors sandblasted and ruined by rock dust. To read more about this intriguing idea, click HERE.

Comet C/2011 L4 PANSTARRS on June 9, 2012 from Port Wing, Wis. Credit: William Wiethoff

I also wanted to update you on Comet L4 PANSTARRS, which is expected to become a bright morning comet next March. PANSTARRS continues its slow westward trek through Scorpius on its way to Libra the Scales tomorrow night. I followed the comet two nights ago and found the little guy shining at magnitude 12.5.

If you’re planning to observe it, look for a very small blob with a brighter center. On close scrutiny you might be able to see the comet’s coma extending to the east as a small hood visible in the photo at right. Use the chart and link below to guide you there.

Chart showing Comet L4 PANSTARRS (see below for details) each night around 11 p.m. CDT now through June 22. North is up and east to the left. Click chart to go to a larger, easier-to-read version you can download. Credit: Emil Bonnano's MegaStar software