Supernova to Destroy Earth! Sometime...

[Scupperer]

A star that's closer than thought is on "the verge" of going supernova: T Pyxidis

3,260 light years - is that really close enough to sterilize?

[IntLibber]

A star that's closer than thought is on "the verge" of going supernova: T Pyxidis

3,260 light years - is that really close enough to sterilize?

Oh yes. Thats as dangerous for our collective productivity as a scrotum bomb is for a certain Nigerian....

[hanelyp]

The bit about radiation from a supernova destroying the ozone layer strikes me as fishy. Ozone is constantly created and destroyed by UV from the sun. An X-ray & gamma burst from a supernova would probably break apart a great deal of ozone, as well as a fair amount of O2, the resulting atomic oxygen having a fair chance of latching onto an O2 and creating more ozone. Whatever disruption there is to ozone is at most temporary.

[Skipjack]

Phil Plait disagrees. No "death from the skies" from that one...

http://blogs.discovermagazine.com/badas ... pe-us-out/

But even with their added power, a Type Ia just doesn’t have the oomph needed to destroy our ozone layer (as the press release indicates) from 3300 light years away

It looks like Sion used the wrong numbers for the gamma ray emission for a Type Ia event, instead using the emission from a gamma-ray burst… a far, far, far more energetic event, and dangerous from several thousand light years away

[Carl White]

A star that's closer than thought is on "the verge" of going supernova: T Pyxidis

3,260 light years - is that really close enough to sterilize?

By "on the verge" they meant "within several million years".

No one seems to be considering that stars move relative to each other. Where will this star be in five million years relative to the Sun? It could end up ten thousand light years away by then.

[Skipjack]

And again... It would have to be MUCH closer.

[Tom Ligon]

We had about the same discussion over at analogsf.com. Dr. C. W. Johnson, our resident astrophysicists, says his best info for the kill radius of a Type 1A supernova is around 120 LY.

I like to point out a Wolf/Rayet star, WR104, around 8000 LY away, that is probably more dangerous. These massive stars only live around 100,000 years, so the timeline to explosion is shorter. They may die in a gamma-ray burst, and have hypernova energies. What makes WR104 particularly nasty is it apparently has a pole pointed within 16 degrees of Earth, so a powerful polar jet could be aimed right at us. In that case it might be dangerous here.

Earth has probably survived relatively nearby supernovae many times before. One possible effect may be to trigger an ice age, via some interaction between cosmic rays and the upper atmosphere. In other words, maybe a cure for AGW?

[Skipjack]

Dr. C. W. Johnson, our resident astrophysicists, says his best info for the kill radius of a Type 1A supernova is around 120 LY.

I think it is more like 20 LYs usually, maybe 50, but 120 ly is nevertheless much closer than 3000...
Yeah gamma ray bursts can be a lot meaner. You have to be really unlucky though to get hit by one. The problem is that by the time you know that it is comming, it is already to late...

Phil Plait had a post about GRBs:
http://blogs.discovermagazine.com/badas ... rosshairs/