Hurtling Star on a Path to Clip Solar System (!)

Hurtling star on a path to clip solar system - New Scientist, 15 March 2010

"A star is hurtling towards us. It will almost certainly clip the outskirts of the solar system and send comets towards Earth.

Vadim Bobylev of the Pulkovo Observatory in St Petersburg, Russia, modelled the paths of neighbouring stars using data from the European Space Agency's Hipparcos satellite and from ground-based measurements of the speeds of stars. He found four previously unidentified stars that will pass within roughly 9.5 light years of Earth. They will tug on the Oort cloud, a diffuse cloud of icy objects around the solar system thought to be a reservoir of comets.

However, the biggest threat comes from another star, Gliese 710, an orange dwarf now some 63 light years away but zooming our way at 14 kilometres per second. Bobylev's calculations suggest Gliese 710 has an 86 per cent chance of passing through the Oort cloud. This could scatter millions of comets into paths that cross Earth's orbit..."

17 4-Ever

Just a little incentive for SAT to check her blog.

You are never too old to be a tween.

Happy Almost Birthday.

Wait, it did what?

The Chilean earthquake that killed more than 700 people on Saturday probably shifted the Earth's axis and shortened the day, according to a NASA scientist.

Richard Gross, a geophysicist at NASA's Jet Propulsion Laboratory in Pasadena, California, told Bloomberg that the 8.8-magnitude quake is likely to have moved the Earth's axis by 2.7 milliarcseconds - about 8 centimetres - and shorted the day by about 1.26 microseconds.

Gross used the same model to estimate the shift caused by the 2004 Sumatran earthquake that caused the Indian Ocean tsunami. That quake had a magnitude of 9.1, shifted the Earth's axis by 2.3 milliarcseconds and shortened the day by 6.8 microseconds.

Gross said the fact that the Chilean earthquake was in the Earth's mid-latitudes, instead of near the equator, meant it will have shifted the axis further despite being smaller. Plus the fault that caused the Chilean quake dips into the Earth at a slightly steeper angle, making it more effective in moving mass.

The changes caused by earthquakes are permanent, Benjamin Fong Chao, dean of Earth Sciences of the National Central University in Taiwan, toldBusiness Week.