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Posts written in: 2007 May

How to survive a little longer in a black hole

May 20th, 2007, under , ,

As anyone who has read Hawking knows, you turn into spaghetti after you cross a black hole’s Event Horizon. The Illustrated Brief History of Time even has a picture of this.

It is common knowledge, of course, that you are doomed after you cross this boundary, and the only question is how much time you have left. In this sense, black holes are not all that different from HIV or cancers. However, unlike with HIV and cancer, the common answer to “what should I do” in the case of black holes has been “nothing, because just like in quicksand, the more you do the faster you get crushed by the singularity”.

A new study reported in Nature disagrees. It notes that the “do nothing” plan is only applicable if you have crossed the Event Horizon in zero velocity. In reality, however, one probably rarely does that (how often one actually crosses the Event Horizon altogether is another question). Instead, one tends to fall into a black hole with an initial non-zero velocity, and in that case the advice, it seems, is to counter your velocity so that it drops to zero.

In other words, if you were travelling north 50 km/h in your Ford Fiesta before you crossed the Event Horizon, you better hit the reverse, and speed just enough to attain a velocity of 50 km/h travelling south, so that your total velocity will be zero. It won’t save you, but it will buy you some extra time.

Green tea kills ya!

May 12th, 2007, under , ,

Apparently, drinking green tea in large quantities can cause kidney and liver damage. The New Scientist article reporting about this mentions that “up to 10 small cups of green tea a day is fine”. Rather unscientifically, it doesn’t tell us what the volume of a “small cup” is, but I take it to be around 200mL. This would mean that it’s still ok to drink up to 2 litres of green tea a day. I’ll need to keep that in mind, as my cups are 0.7L, and I can easily drink three of them a day (although I keep switching between green and rooibos tea).

Those taking green tea supplements should, however, apparently be somewhat concerned.

NASA unveils James Webb

NASA has unveiled the James Webb Space Telescope, which will replace the Hubble Space Telescope in 2013. A BBC News article gives the details.



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