Tunguska-sized asteroid to skim Earth tomorrow closer than the moon, some satellites

A newly-discovered asteroid is incoming fast, and astronomers calculate that it will skim by Earth by only about 40,000 miles. That's closer to Earth than the moon., and closer than some satellites  stationed in a High Earth Orbit.

The new asteroid, 2009 DD45,  was spotted by prolific comet-hunter Rob McNaught  about two days ago at Australia"s Siding Spring Observatory. DD45 is estimated to have a diameter of about 115 feet, or roughly the size of the asteroid (120 feet) that slammed into Tunguska in Siberia  in 1908.

That disastrous impact slammed the energy of about 150 Hiroshima-sized bombs into the Siberian countryside. NASA's Near-Earth Object office has details:

...Eight hundred square miles of remote forest had been ripped asunder. Eighty million trees were on their sides, lying in a radial pattern.The massive explosion packed a wallop.

...The resulting seismic shockwave registered with sensitive barometers as far away as England. Dense clouds formed over the region at high altitudes which reflected sunlight from beyond the horizon. Night skies glowed, and reports came in that people who lived as far away as Asia could read newspapers outdoors as late as midnight. Locally, hundreds of reindeer, the livelihood of local herders, were killed, but there was no direct evidence that any person perished in the blast.

DD45 is expected to speed past Earth somwehere over the Pacific Ocean near Tahiti at about 6 a.m. PST March 2. Racing at about half a degree per minute, the asteroid will be in the constellation of Virgo, with a magnitude of slightly more than 10.

NASA has provided a plot of DD45's path here. 

Image: artist's concept of asteroid impact on Earth/NASA