General Discussion > Science & Nature

Scientific Picture of the Week (another new feature)

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Simon:

Clive:
This is a truly awesome photo of the very centre of our Milky Way galaxy.  If you want to know which direction to look for it, look towards south on any clear night this month and you will see the very bright planet Jupiter.  After the Sun and the Moon, Jupiter is currently the brightest object in the sky.  A the moment, Jupiter lies in front of  the constellation of Sagittarius which is the direction of the galactic centre.  The black  hole at the centre can't be seen but we know it's there because the 10 million stars in Sam's photo are all orbiting it at breakneck speeds of 5 million kph.  Calculations show that in order for the stars to orbit at that speed the unseen object must have a mass of at least 2.6 million suns.   ;)

Simon:
It's just mind boggling, isn't it?

GillE:
Very interesting explanation of how to observe a black hole, Sam - thanks.

It would appear my language wasn't terribly precise when I said "the contents of a novel could be hidden in a photo like that".  I meant it literally!  Apparently, by varying the pixels in a photograph that size just slightly, it's possible to conceal a whole book of text in the image.  Osama Bin Laden's lot has used that technique extensively in the past, especially in photos on eBay.  It makes you wonder, doesn't it?

sam:

--- Quote from: GillE on August 07, 2008, 23:31 ---Very interesting explanation of how to observe a black hole, Sam - thanks.

It would appear my language wasn't terribly precise when I said "the contents of a novel could be hidden in a photo like that".  I meant it literally!  Apparently, by varying the pixels in a photograph that size just slightly, it's possible to conceal a whole book of text in the image.  Osama Bin Laden's lot has used that technique extensively in the past, especially in photos on eBay.  It makes you wonder, doesn't it?

--- End quote ---

Oh yeah, I've come across that before - I actually have a tool that can do that (somewhere) - its fairly simple stuff to break though.. so I wouldn't worry - but quite useful to hide stuff from prying eyes who have no idea.

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