by Boldra » Tue Jun 28, 2005 2:13 pm
I found the usage of "false colour" in
todays APOD somehow incongruent... Surely it's enough to say that there are radio waves visible in the above image without saying that they're falsely coloured? What colour do people think radio waves are anyway?
I realise this kind of thing can cause all sorts of confusion for some, but what's next...?
Explanation: Together, the radio lobes span over one million light years (light years are a distance, not a time) -- what caused them? In the center is a large but peculiar elliptical galaxy (galaxies are not the same thing as solar systems, they're much bigger) dubbed NGC 1316. Detailed inspection of the NGC 1316 system indicates that it began absorbing a small neighboring galaxy about 100 million years ago (actually much longer, but what we're seeing now happened 75 million years ago) . Gas from the galactic collision has fallen inward toward the massive central black hole, with friction heating the gas to 10 million (celsius or fahrenheit, you choose) degrees. For reasons not yet well understood, two oppositely pointed fast moving jets (jets as in jacuzzi, not jets as in airport) of particles then developed, eventually smashing into the ambient material on either side of the giant elliptical galaxy (because space isn't really empty). The result is a huge reservoir of hot gas that emits radio waves, observed as the orange (false-color) radio lobes in the above image. The radio image is superposed on an optical survey image of the same part of the sky (which might not have been falsely coloured, but the spikes on the stars definitely aren't really there). Strange patterns in the radio lobes likely indicate slight changes in the directions of the jets.
Maybe the solution is to just have a disclaimer somewhere: "Images appearing on this site may not match what you would see with your own eyes (YMMV)"?
* apologies if you're confused by the different spellings of
colour in this post, they were mostly intentional.
I found the usage of "false colour" in [url=http://antwrp.gsfc.nasa.gov/apod/ap050628.html]todays APOD[/url] somehow incongruent... Surely it's enough to say that there are radio waves visible in the above image without saying that they're falsely coloured? What colour do people think radio waves are anyway?
I realise this kind of thing can cause all sorts of confusion for some, but what's next...?
[quote][color=brown][b]Explanation:[/b][/color] Together, the radio lobes span over one million light years [color=brown][b](light years are a distance, not a time)[/b][/color] -- what caused them? In the center is a large but peculiar elliptical galaxy [color=brown][b](galaxies are not the same thing as solar systems, they're much bigger)[/b][/color] dubbed NGC 1316. Detailed inspection of the NGC 1316 system indicates that it began absorbing a small neighboring galaxy about 100 million years ago [color=brown][b](actually much longer, but what we're seeing now happened 75 million years ago)[/b][/color] . Gas from the galactic collision has fallen inward toward the massive central black hole, with friction heating the gas to 10 million [color=brown][b](celsius or fahrenheit, you choose)[/b][/color] degrees. For reasons not yet well understood, two oppositely pointed fast moving jets [color=brown][b](jets as in jacuzzi, not jets as in airport)[/b][/color] of particles then developed, eventually smashing into the ambient material on either side of the giant elliptical galaxy [color=brown][b](because space isn't really empty)[/b][/color]. The result is a huge reservoir of hot gas that emits radio waves, observed as the orange (false-color) radio lobes in the above image. The radio image is superposed on an optical survey image of the same part of the sky [color=brown][b](which might not have been falsely coloured, but the spikes on the stars definitely aren't really there)[/b][/color]. Strange patterns in the radio lobes likely indicate slight changes in the directions of the jets.
[/quote]
Maybe the solution is to just have a disclaimer somewhere: "Images appearing on this site may not match what you would see with your own eyes (YMMV)"?
* apologies if you're confused by the different spellings of [i]colour[/i] in this post, they were mostly intentional.