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Astronomy Stuff


Chinahand

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  • 2 weeks later...
  • 2 months later...

A star exploded about 25 million light years away.

 

Just stop and think about that distance - its 146 billion billion miles.

 

And that star blew up 25 million years ago - when the only simian was something like a lemur, and the Mediterranean sea had still not been formed by the movement of the tectonic plates between Africa and Europe.

 

So 25 million light years away, and 25 million years ago - guess what ... the light of that explosion has just reached us.

 

ptf11kly_arrow-1023x578.jpg

 

Link

 

Amazingly astronomers were looking at the same patch of sky and so have been able to capture the explosion basically right from its beginning.

 

Over the next 10 or so days it should get brighter and brighter.

 

At the moment it is totally invisible for anyone without a massive telescope, but over the next 10 days it could become visible with binoculars or a small telescope.

 

The supernova is in the Pinwheel Galaxy M101 which is in the constellation the Great Bear - the Plough which points to the Pole Star is a part of this constellation so it's reasonably famous.

 

heic0801h.jpg

 

The energy released from the explosion is probably going to make the star give out more energy than the entire galactic core over the next few weeks.

 

We are lucky enough to be far enough away to just enjoy it!

 

If you've a telescope or binoculars try and get out and see it - the moon won't be too bright which will help alot.

 

Seeing a supernova is a pretty unique experience - enjoy!

 

SN1994D.thumb.jpg

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A star exploded about 25 million light years away.

Fascinating issue. Some factoids:

This is supposed to be a Type Ia supernova, when a white dwarf star accretes stellar material, usually from a companion star, and above a certain mass limit, it explodes.

Type Ia supernovae are important cosmologically, as they can be used as "standard candles", i.e. a known intensity of light source, thereby enabling the distance to the star to be determined accurately and ultimately leading to estimates about the expansion rate of the universe.

Its eventual brightness depends on the star's "metallicity". Astronomers define "metals" in stars as anything other than hydtogen and helium, which annoys other scientists mightily.

Regarding duration of brightness, found this graph (source http://www-astro-the...resentation.ppt). The luminosity was increasing exponentially last week, so it's probably still in the 5-15 days timescale. You'll still need at least a good pair of binoculars to see it at its peak in maybe a couple of weeks, though.

post-2446-0-53036800-1314637397_thumb.gif

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NASA's Juno probe turned its gaze back towards the earth and put humanity and all of life in context a few days ago.

 

The moon is on the right - all of history and all we have directly touched (apart from Neil Armstrong and 11 colleagues) is on the left.

 

583510main_juno20110830-full.jpg

Edited by Chinahand
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  • 4 months later...

The end is nigh!

http://www.bbc.co.uk/news/science-environment-16756450

An asteroid will pass by the Earth on Friday in something of a cosmic near-miss, making its closest approach at about 1600 GMT.

The asteroid, estimated to be about 11m (36ft) in diameter, was first detected on Wednesday.

At its closest, the space rock - named 2012 BX34 - will pass within about 60,000km of Earth - less than a fifth of the distance to the Moon.

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20% of the distance to the moon sounds pretty close, and as Albert said we haven't had much notice. Presumably, there is plenty more stuff out there like this, although I assume that the really big asteroids are tracked or at least would tend to be picked up further away.

 

An 11m asteroid sounds like it is just a bit smaller than the object that caused the Tunguska event in 1908, estimated to have been several 10s of metres in diameter. When one of these objects nexts hits the Earth, it will potentially be pretty noticeable, given how much human settlement has spread across the planet.

 

Keep in mind that whatever caused the Tunguska event released energy in the same sort of range as a thermonuclear weapon.

 

http://en.wikipedia.org/wiki/Tunguska_event

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