Tunguska Centenary

What was it? Anti-matter explosion? Alien spacecraft? Or a meteoroid? Whatever it was, it happened 100 years ago today in remote Siberia…

The Tunguska Event or explosion

was most likely caused by the air burst of a large meteoroid or comet fragment at an altitude of 5–10 kilometres (3–6 miles) above Earth’s surface. Different studies have yielded varying estimates for the object’s size, with general agreement that it was a few tens of metres across.

Although the meteor or comet burst in the air rather than directly hitting the surface, this event is still referred to as an impact. Estimates of the energy of the blast range from 5 megatons to as high as 30 megatons of TNT, with 10–15 megatons the most likely – about 1000 times as powerful as the bomb dropped on Hiroshima, Japan and about one third the power of the Tsar Bomba, the largest nuclear weapon ever detonated. The explosion knocked over an estimated 80 million trees over 2,150 square kilometres (830 square miles). It is estimated that the earthquake from the blast would have measured 5.0 on the Richter scale, which was not yet developed at the time. An explosion of this magnitude is capable of destroying a large metropolitan area. [Wikipedia]

Of course, anyone familiar with the X-Files knows the real story. 😉

links for 2008-05-13

  • is a national, grassroots nonprofit organization dedicated to increasing, preserving and protecting America’s roadless public lands. Today there are Broads of all ages and both genders in every state in the union making their voices heard to protect America’s last wild places.

St. Patrick’s Day 2008

Happy Saint Patrick’s Day, however you may or may not observe it. (Probably not…)

As far as I can tell, the Irish branch of my family (Boyle, through my paternal grandfather) were ‘orange’ Irish, not ‘green’, thus it never was a big deal for him. Well, being a teetotaler was perhaps a factor.

So chase those snakes out of the Emerald Isle of your stomachs via green beer and whiskey if you have such a hankerin’. I’ll be available to drive if need be, plus, I promise to not make much noise around here tomorrow morning.

[later, via Ed] A Guide to Irish stouts, ales, and porters.

Winter Session

We’re heading into the “16 straight 14-hour days of teaching Geology Field School” season for Audrey. The best part is you get a semester’s worth of TA-ing out of the way prior to the semester. The bad part is you enter the semester depleted.

They’re going to be down in those heavily faulted ranges with a series of calderas along the west side of the Colorado River. Posting will occur when possible.

Audrey’s Dissertation Proposal Defense is Today

At 1 p.m. (PST) Audrey will defend her dissertation proposal: The Role of Subsurface Carbon Dioxide in the Formation of Martian Rampart Craters and the Geology of Meridiani Planum, Mars. This is the partial culmination of a great deal of work and I am very proud of her. I’m sure she will be accepting good thoughts via the ethers…

Go get ’em, Tiger. 🙂

[evening update:] Things went extremely well! Her committee was very receptive and offered only a few suggestions, none of them mandatory. Excellent job! After Ian went to bed she said, “see you Wednesday,” and headed off to bed herself.