“a true blast from the past..”
[Image credit: NASA/JPL-Caltech]. I had mentioned just how really big space is. Left is an image of M33, one of our closest galactic neighbours at just 2.9 million light-years away, viewed in ultraviolet – to show recent star formation – by the Galaxy Evolution Explorer, celebrating 6 years in operation, and in infrared by the Spitzer Space Telescope. Below is an image of one of our most distant relatives, also from Spitzer. With a red shift of 8.2, corresponding to a distance of around 13.035 billion light years, when the Universe was only 630 million years old, Gamma Ray Burst 090423 is the most distant cosmic explosion detected yet. [Second Image Credit: NASA/Swift/Stefan Immler.] Telescopes, eh? Just be thankful it wasn’t closer.. Oh, and Europe’s Herschel and Planck telescopes will be launched on 14 May.
Just to confirm that I also am a big fan of these deep space images and I find them awe inspiring.
Keep delivering.
how can we know that anything more than a few light years away is still there? These are pictures of the distant past surely
Malachi,
You’re almost right. But it’s not a couple of light years. It’s anything beyond the distance that light can travel in the minimum human attention span. Light travels at around 186,000 miles per second.
So when you look up at the sun and feel comforted that it’s still there, you could be mistaken; it may have blown apart up to about 5 minutes or so ago.
Even the sunlight reflected from the moon takes about 1 1/4 seconds to reach earth.
Incidentally, that’s also the reason why there’s a slight delay in a telephone conversation when the signal is relayed via a geosynchronous satellite.
them maybe we have a smaller universe than we suppose
malachi ,
‘maybe we have a smaller universe than we suppose’
Northern Ireland is a very small ‘universe’. There are those who wish it was in a far off galaxy not too distant from a gamma ray burst
On the subject of large numbers . Once you pass the billion mark the human mind seems not up to the task of practically envisioning such vast distances .
The same phenomenon is now alas also found when one tries to envision say the USA’s 3 trillion dollar ‘bail out ‘ or it’s 14 trillion dollar debt .
To bring the latter down to a human scale . If you sat a table and started counting out ten dollar notes one at a time going back in history by the same amount of time it takes you to count each note then you would finally count out the last ten dollar bill about 300,000 years ago or at least 100,000 years before Homo Sapiens emerged as a species
Joe, if you think about the quatization of space into blocks of shapes (which you touched on in Peter’s other thread), the speed of light may vary from one block/unit to the another, ultimately changing the time for light to travel.
If space can be quantized into blocks of space, views from hubble may be like viewing through a collideascope.