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Drakheim
2005-Mar-04, 04:36 PM
Is there any real answer on how far away a hypernova would have to occour for it to not be lethal to Earth?

Majin Vegeta
2005-Mar-04, 05:28 PM
Depends, How Many Solar Masses are you talkin'?

Romanus
2005-Mar-04, 06:14 PM
IIRC, the term "hypernova" is gradually falling out of favor, as GRBs are seen increasingly as the result of regular supernovae with jets that happen to be pointed in Earth's direction. If that's the case, then hypernovae aren't much different from regular supernovae in terms of their range of lethality. From what I've read, a SN at 100 light-years would be rough on the biosphere. At 30 light-years, we're probably looking at a mass extinction of some kind. At 10 light-years, we'd break out the time capsules. All this is under the Earth's atmosphere; in space the lethal range without shielding would likely be much greater.

Majin Vegeta
2005-Mar-04, 06:44 PM
*cough* Doesn't anyone remember Eta? 120 Solar Masses at 7K lightyears away? When that thing pops the earth will go bye-bye, Because of the power, radiation, and a bunch of other **** ****! :lol: (i censored myself)

Drakheim
2005-Mar-04, 06:55 PM
Depends, How Many Solar Masses are you talkin'?

Yes, I was asking more for ETA Caraine. I think that star is 120 - 150?

I am not worried at all about not waking up tomorrow if that star were to blow, I was just curious as to how many systems in it's polar paths were going to be rendered sterile.

the_shaggy_one
2005-Mar-04, 07:07 PM
we've had many threads here about the threat posed by Eta Car, and the general consensus I get is that it's not really a threat to us. It would just make it easier to read at night for a couple days :P

Glom
2005-Mar-04, 11:46 PM
A nearby supernova can cause major climatic changes that can be troublesome. A supernova is a suspect for the recent Little Ice Age.

Ilya
2005-Mar-05, 02:05 AM
IIRC, the term "hypernova" is gradually falling out of favor, as GRBs are seen increasingly as the result of regular supernovae with jets that happen to be pointed in Earth's direction. If that's the case, then hypernovae aren't much different from regular supernovae in terms of their range of lethality. From what I've read, a SN at 100 light-years would be rough on the biosphere. At 30 light-years, we're probably looking at a mass extinction of some kind. At 10 light-years, we'd break out the time capsules. All this is under the Earth's atmosphere; in space the lethal range without shielding would likely be much greater.

So re-phrase the question: How far away a GRB (supernova with its magnetic pole pointed at Earth) would have to occour for it to not be lethal to Earth?

AFAIK, Eta Carinae's poles DO NOT point at Earth, so when it blows up, from our viewpoint it won't be a GRB.

Jobe
2005-Mar-05, 06:31 AM
you have to take into account other variables than distance! how big an event are we talking here?

Glom
2005-Mar-07, 02:37 PM
But I thought the interesting thing about GRBs was that they are so distant that they have to be something more powerful.

Feezle
2005-Jun-15, 11:57 AM
*cough* Doesn't anyone remember Eta? 120 Solar Masses at 7K lightyears away? When that thing pops the earth will go bye-bye, Because of the power, radiation, and a bunch of other **** ****! :lol: (i censored myself)

Not sure, I think ya might wanna' look it up again, :oops: but last I checked, if Eta C were somewhat less than 3K ly, it may cause serious trouble here (mass extinction, yadayada) but at > 7K ly, probably not a major threat to Earth when it goes (and it WILL go) BOOM ... However, it may be one pretty sight !!! It could go soon too, cosmically speaking, in as little as 25K yrs, and if certain current thought is close and VERY massive stars go SNe/Hypernova after core collapse and subsequent ingestion of the original envelope as dense accretion disk after t=1 day, (assuming correct viewing angle of rotational axis and existence of "cannon ball" mechanism in pulsed beam is correct; see: http://arxiv.org/abs/astro-ph/0101007 for a discussion), WOW WOW WOW ... Eta C, as possibly most massive star in MW should be incredible sight when it goes. THAT would be sumpin to see :o

mickal555
2005-Jun-15, 12:45 PM
I'd rather eta go in my lifetime than not. It's a lonnnnnnnnnnnnnnng way away and we'd be fine I reakon.

Feezle
2005-Jun-15, 07:54 PM
But I thought the interesting thing about GRBs was that they are so distant that they have to be something more powerful.


you have to take into account other variables than distance! how big an event are we talking here?

Glom: The interesting thing about GRB's IS that they are the most powerful event in the observable universe. So your question is moot in reference to "something more powerful". Clearly a SNe/GRB progenitor of 120 Ms will produce a jet more "powerful" than a progenitor of 50 Ms.

Jobe: "How big an event?" .... "BIG" .... I believe Dr. Martin Reese, the Astronomer Royal, equated the GRB's 'power output' (and correct me please if I am wrong :oops: ) to "All the observable galaxies in the universe" .... OK, so that's rather "BIG" ...

Should we be surprised? Uh, no. Prior to the current excitement over GRB's it was routinely splashed around that SNe, specifically of Type II (Core collapse model, as opposed to Type Ia/b/c which are accretion models) routinely outshine (regardless of their peak energy wavelength) the 100G to 400G stars of their host galaxy.

Really the ONLY parameters in determining a GRB's effect on a given system are: It's distance and it's alignment. It seems likely that there are no ultra massive stars, the progenitors of GRB's, currently in our local galactic neighborhood, (Eta C is far far away) although there ARE stellar nurseries not TOO far away (and it seems likely, as per astronomer Woolsey, who with Reese sort of formulated the latest picture, that GRB progenitors are likely born in the same stellar nurseries as most other type stars, and are therefore likely indicators of these stellar nurseries). AND .... it seems that these progenitors live only a few million years and therefore do not travel far from the "nursery" in which they are born, which precludes one moving close enough to US to be a threat.

It then seems that we are likely safe for some time to come. i.e; The ultra massive progenitor star would have to be both relatively near AND it's rotational pole (NOT it's magnetic pole) would have to point nearly at us for it to be a worry.

Pretty good bet that Sol will go the way of Betelgeise (sp?) and eat our home before an 'Ultra Massive' star goes SNe/GRB on us. OR, a large chunk such as a comet or an asteroid will wipe life as we know it from Momma Terra.

Either way, you'll likely be able to wake tomorrow and while eating that long yearned for donut, smile with the knowledge that a GRB ain't likely to erase your debt to the IRS .........

Have a nice day ..... :D