SAN FRANCISCO — Hours after a meteor exploded over Russia and injured more than 1,000 people and an asteroid passed relatively close to Earth, residents in California reported seeing an unusual flash of light over the San Francisco Bay area that left many startled and thrilled.
Based on reports, the light streaking in the Northern California sky was a sporadic meteor, or fireball, and not a major event, said Mike Hankey, operations manager for the American Meteor Society, based in Genesee, N.Y. The group recorded at least 35 reports of the event, he said.
"Fireballs happen every single night, all around the world," he said.
Experts say smaller meteorites hit earth five to 10 times a year but chances of a large meteor passing, such as the one that streaked over Chelyabinsk, Russia, are much rarer. Another meteor landed in the Bay Area in October and caused a loud sonic boom, a sound that could have been from the meteor traveling faster than the speed of sound, officials said at the time.
Another meteor that exploded April 22 was seen over a large part of Northern California and Nevada.
On Friday, the Chabot Space and Science Center in Oakland also reported receiving calls describing what appeared to be a fireball flying west around 8 p.m.
Jonathan Braidman, an instructor at the center, described the object based off reports as likely being a small piece of an asteroid that "somehow" got on a collision course with the earth.
"This is a very common occurrence," Braidman said. "What is uncommon is that it's so close to where people are living."
Bay Area media outlets reported the fireball was reported seen from an area stretching from Gilroy, about 80 miles south of San Francisco, to Sacramento, about 90 miles to the northeast.
One viewer told television station NBC11 the object appeared bluish in color and appeared to be heading straight to the ground. San Leandro resident Krizstofer Loid told KTVU-TV that he was sitting on a lawn chair in the backyard of his home when he saw the object.
"I saw, like, a blue streak from the sky coming down. I thought it was fireworks, but I didn't hear any sounds," he said.
The center's large telescopes did not pick up the object during a stargazing event, astronomer Gerald McKeegan told KGO-TV.
"The media attention on the Russian thing got people's attention, so they're more likely to notice things in the sky," said Mike Hankey, operations manager of the American Meteor Society.
While Friday night's fireball received a lot of attention in the San Francisco Bay area, Braidman notes about 15,000 tons of debris from asteroids enter the earth's atmosphere every year.
"Usually these things break up into small pieces and are difficult to find," he said.
Earlier on HuffPost:
How Big Is It?
DA14 is about 150 feet wide, which is about the same size as the White House.
How Fast Is It Going?
DA14 will speed past the earth at about five miles per second -- approximately <a href="http://www.telegraph.co.uk/science/space/9856539/Nasa-2012-DA14-asteroid-will-not-impact-Earth.html">eight times as fast</a> as a bullet from a rifle.
How Close Will It Get?
The asteroid will pass within 17,200 miles of earth. In comparison, geosynchronous satellites orbit the earth at an altitude of 22,300 miles. In the image at left, each white dot represents a satellite --with the horizontal ring of dots indicating satellites in geosynchronous orbit. Don't worry -- DA14 isn't expected to collide with any satellites.
DA14 will make a repeat appearance in 2046, when it will pass about 620,000 miles from earth -- that's about three times the distance to the moon. The asteroid's orbit around the sun is similar to earth's, which means it comes relatively close to our planet <a href="http://www.slate.com/blogs/bad_astronomy/2013/02/11/asteroid_2012_da14_space_rock_will_miss_the_earth_by_17_000_miles.html">twice each orbit</a>.
When Was DA14 Discovered?
<a href="http://www.nasa.gov/topics/solarsystem/features/asteroidflyby.html">DA14 was discovered</a> on Feb. 23, 2012 by astronomers at the Astronomical Observatory of Mallorca in Spain. At left, an early observation of the asteroid.
If It Hit...
There's no chance that DA14 will hit earth, but if it did, we might be in trouble. In 1908, a space rock about the same size as DA14 struck Tunguska, Russia, <a href="http://www.livescience.com/27000-flyby-asteroid-da14-tunguska.html">leveling an area of about 800 square miles</a> and releasing as much energy as 185 Hiroshima bombs. A direct hit of this magnitude could easily wipe out a major city.
Other Near-Earth Objects
D14 isn't the only asteroid in the sky. NASA is tracking 9,693 <a href="http://neo.jpl.nasa.gov/faq/#howmany">so-called Near-Earth objects</a>. Of these, 1,378 are classified by NASA/JPL as Potentially Hazardous Asteroids. That means they're large enough and will come close enough to earth to merit further observation.
How often do asteroids the size of DA14 hit the earth? About once <a href="http://www.livescience.com/27000-flyby-asteroid-da14-tunguska.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+Livesciencecom+(LiveScience.com+Science+Headline+Feed)">every 1000-2000 years</a>, according to Mark Boslough, a physicist at Sandia National Laboratories.
What's It's Made Of?
DA14 is probably made of iron, magnesium, silicon and other metals, <a href="http://www.space.com/19758-asteroid-worth-billions-2012-da14-flyby.html">Michael Busch, a Fellow at the National Radio Astronomy Observatory</a>, told SPACE.com. There may also be ice clinging to the asteroid. If the asteroid were on earth, the water and metals might be worth nearly $200 billion, <a href="http://www.space.com/19758-asteroid-worth-billions-2012-da14-flyby.html">according to officials</a> at Deep Space Industries, a company that hopes to one day mine asteroids.
How To Watch
You can watch a live broadcast from NASA on HuffPost Science starting at 2 p.m. EST on Feb. 15.