<p>Adding to Oceanescence's mention of Gamma Ray Bursts, someone's recently done some calculations: <a href="http://www.universetoday.com/117259/gamma-ray-bursts-limit-the-habitability-of-certain-galaxies-says-study/" rel="nofollow">Gamma Ray Bursts Limit The Habitability of Certain Galaxies, Says Study</a></p>

<blockquote>
  <p>In fact, according to the authors of the new paper, there is a 90% chance that a GRB powerful enough to destroy Earth’s ozone layer occurred in our stellar neighborhood some time in the last 5 billion years, and a 50% chance that such an event occurred within the last half billion years. These odds indicate a possible trigger for the second worst mass extinction in Earth’s history: the Ordovician Extinction. This great decimation occurred 440-450 million years ago and led to the death of more than 80% of all species.</p>
</blockquote>

<p>Gamma ray bursts are thought to emerge from the <em>poles</em> of supernova, so a star's spin axis would have to be in the right direction for it to hit us. Betelgeuse, a nearby supernova candidate has it's spin axis at <a href="http://en.wikipedia.org/wiki/Betelgeuse" rel="nofollow">an inclination of about 20° to the direction of Earth</a>, so that star is not likely to get us when she blows. However, we don't have accurate information on the direction of the spin axis of <em>most</em> stars.</p>

CC BY-SA 3.0
2015-01-09T16:04:15.133Z
Excellent! I hadn't considered that. I have some sources of gamma-ray-burst information in my answer [here](http://astronomy.stackexchange.com/questions/2585/how-likely-and-severe-is-the-threat-of-a-gamma-ray-burst-to-earth), if that will help you at all.
HDE 226868
CC BY-SA 3.0
2015-01-09T16:02:55.207Z
2015-01-09T16:02:55.207Z
Wayfaring Stranger
<p>Essentially, anything could happen! We can't really predict events such as you've described.
The only event we can really be certain of is that the Sun will inevitably die in about 5 billion years. When it's almost run out of hydrogen to fuse it will expand into a red giant, becoming so large it will take out the Earth. There's a good video demonstrating this here: <a href="http://science.howstuffworks.com/life/evolution/life-on-earth-end1.htm" rel="nofollow">http://science.howstuffworks.com/life/evolution/life-on-earth-end1.htm</a></p>

<p>You could add geomagnetic reversal and gamma ray bursts to your list. Also see: <a href="http://science.howstuffworks.com/life/evolution/life-on-earth-end1.htm" rel="nofollow">http://science.howstuffworks.com/life/evolution/life-on-earth-end1.htm</a> </p>

CC BY-SA 3.0
2015-01-08T18:04:37.327Z
2015-01-08T18:04:37.327Z
Oceanescence
<p>What kinds of astronomical events can pose a serious threat to life on Earth in the near future (1000-10,000 years). If there are none in the near future, when is the soonest event that is predicted to threaten life on Earth? </p>

<p>I am ignorant about astrononomy and so far I have only thought of an asteroid collision, solar flares, and effects from the sun dying in several billion years (and a visit by some hostile aliens).</p>

CC BY-SA 3.0
2015-01-08T07:30:51.447Z
https://en.wikipedia.org/wiki/Gamma-ray_burst
Deer Hunter
<earth>
Near-future astronomic events that could threaten Earth
math_lover
# Near-future astronomic events that could threaten Earth

(Asked by: username_0 on 2015-01-08)

What kinds of astronomical events can pose a serious threat to life on Earth in the near future (1000-10,000 years). If there are none in the near future, when is the soonest event that is predicted to threaten life on Earth?

I am ignorant about astrononomy and so far I have only thought of an asteroid collision, solar flares, and effects from the sun dying in several billion years (and a visit by some hostile aliens).

**Tags:** earth
> **Comments:**
> **username_1**: https://en.wikipedia.org/wiki/Gamma-ray_burst  

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## 2 answers

### Answer by username_2 on 2015-01-09. Score: 2

Adding to Oceanescence's mention of Gamma Ray Bursts, someone's recently done some calculations: [Gamma Ray Bursts Limit The Habitability of Certain Galaxies, Says Study](http://www.universetoday.com/117259/gamma-ray-bursts-limit-the-habitability-of-certain-galaxies-says-study/)

> In fact, according to the authors of the new paper, there is a 90% chance that a GRB powerful enough to destroy Earth’s ozone layer occurred in our stellar neighborhood some time in the last 5 billion years, and a 50% chance that such an event occurred within the last half billion years. These odds indicate a possible trigger for the second worst mass extinction in Earth’s history: the Ordovician Extinction. This great decimation occurred 440-450 million years ago and led to the death of more than 80% of all species.

Gamma ray bursts are thought to emerge from the *poles* of supernova, so a star's spin axis would have to be in the right direction for it to hit us. Betelgeuse, a nearby supernova candidate has it's spin axis at [an inclination of about 20° to the direction of Earth](http://en.wikipedia.org/wiki/Betelgeuse), so that star is not likely to get us when she blows. However, we don't have accurate information on the direction of the spin axis of *most* stars.

> **Comments:**
> **username_3**: Excellent! I hadn't considered that. I have some sources of gamma-ray-burst information in my answer [here](http://astronomy.stackexchange.com/questions/2585/how-likely-and-severe-is-the-threat-of-a-gamma-ray-burst-to-earth), if that will help you at all.  

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### Answer by username_4 on 2015-01-08. Score: 2

Essentially, anything could happen! We can't really predict events such as you've described.
The only event we can really be certain of is that the Sun will inevitably die in about 5 billion years. When it's almost run out of hydrogen to fuse it will expand into a red giant, becoming so large it will take out the Earth. There's a good video demonstrating this here: <http://science.howstuffworks.com/life/evolution/life-on-earth-end1.htm>

You could add geomagnetic reversal and gamma ray bursts to your list. Also see: <http://science.howstuffworks.com/life/evolution/life-on-earth-end1.htm>


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