A huge asteroid the size of the football stadium has a close encounter with Earth today (Oct. 31) and you can watch the space rock safely fly by online this Halloween. NASA scientists have dubbed asteroid a cosmic "Great Pumpkin" to celebrate the spooky holiday flyby.
The newfound asteroid 2015 TB145 will buzz Earth 1:01 p.m. EDT (1701 GMT), passing by at a safe range of about 300,000 miles (480,000 kilometers), just beyond the orbit of the moon. The asteroid poses no threat of hitting Earth, but it does give astronomers a tantalizing chance to ping the space rock with radar to learn more about what it's like.
Today at 1 p.m. EDT (1700 GMT), the online Slooh Community Observatory will host a free live webcast of asteroid 2015 TB145 to discuss the asteroid's flyby, the "dangers of near-Earth asteroids, the potential fallout of an asteroid this size impacting the Earth or moon and try to understand why it took so long to discover," according to a Slooh statement. You can go to Slooh.com to join and watch this broadcast live, as well as access Slooh's library of past shows.
You can also watch the asteroid flyby webcast on Space.com, courtesy of Slooh. The webcast will be hosted by Slooh's Paul Cox and Slooh astronomer Bob Berman.
NASA scientists have been tracking asteroid 2015 TB145 with optical telescopes and radar tools since the space rock was discovered on Oct. 10 by astronomers using the University of Hawaii's Pan-STARRS 1 telescope. [Halloween Asteroid Flyby: A Guide for Observers]
"We are going to study it with optical, infrared and radar wavelengths," Marina Brozovic, a research scientist with NASA's Jet Propulsion Laboratory in Pasadena, California, said in avideo explaining the asteroid observation plan. The radar images of 2015 TB145 captured during the asteroid's closest approach should offer the best views of the space rock.
"We are expecting them to be really spectacular and that they are going to show a wealth of surface features," Brozovic said.
So far, observations on Friday (Oct. 30) using the Planetary Radar Group at the National Science Foundation's Arecibo Observatory in Puerto Rico have revealed that the asteroid is about 1,968.5 feet (600 meters) wide, "which is larger than expected," according to a statement from the National Astronomy and Ionosphere Center (NAIC), which runs the observatory.
The asteroid also rotates once every five hours, and is hurtling through space at a speed of about 78,293 mph (126,000 km/h), according to the NAIC statement on Facebook.
In addition to the Arecibo Observatory, NASA scientists will use the agency's Goldstone Solar System Radar antenna in Goldstone, California to image asteroid 2015 TB145.
"The close approach of 2015 TB145 at about 1.3 times the distance of the moon's orbit, coupled with its size, suggests it will be one of the best asteroids for radar imaging we'll see for several years," JPL scientist Lance Benner, who leads NASA's asteroid radar research program, said in a statement. "We plan to test a new capability to obtain radar images with two-meter resolution for the first time and hope to see unprecedented levels of detail."
The Halloween flyby will be the closest approach of an object as large as asteroid 2015 TB145 until 2027, when an asteroid even larger - the 2,600-foot (800 m) object called 1999 AN10 - will pass Earth at a range of 238,000 miles (383,023 km), or about the same distance between the Earth and moon.