Sunday, December 02, 2007

New Hubble Image - Messier 74


Science Daily posted the news item about this new image from the Hubble Telescope.

Hubble has sent back an early Christmas card with this new NASA/ESA Hubble Space Telescope image of the nearby spiral galaxy Messier 74. It is an enchanting reminder of the impending season. Resembling glittering baubles on a holiday wreath, bright knots of glowing gas light up the spiral arms, with regions of new star birth shining in pink.

Messier 74, also called NGC 628, is a stunning example of a 'grand-design' spiral galaxy that is viewed by Earth observers nearly face-on. Its perfectly symmetrical spiral arms emanate from the central nucleus and are dotted with clusters of young blue stars.

In the new Hubble image we can also see a smattering of bright pink regions decorating the spiral arms. These are huge, relatively short-lived, clouds of hydrogen gas which glow due to the strong radiation from hot, young stars embedded within them; glowing pink regions of ionized hydrogen (hydrogen that has lost its electrons). These regions of star formation show an excess of light at ultraviolet wavelengths and astronomers call them HII regions.

Tracing along the spiral arms are winding dust lanes that begin very near the galaxy's nucleus and follow along the length of the spiral arms. These spiral arms are not actually static 'arms' like spokes on a wheel. They are in fact density waves and move around the galaxy's disc compressing gas -- just as sound waves compress the air on Earth -- creating a new generation of young blue stars.

Messier 74 is located roughly 32 million light-years away in the direction of the constellation Pisces, the Fish. It is the dominant member of a small group of about half a dozen galaxies, the Messier 74 galaxy group. In its entirety, it is estimated that Messier 74 is home to about 100 billion stars, making it slightly smaller than our Milky Way.

Read the rest.


3 comments:

Unknown said...

Yeah, yeah, it's very pretty. But with only 100 billion stars, it's a pipsqueak galaxy. I mean, if you go there, can you find a good cup of coffee?

And it's called "messier." Do you think, maybe, that's for a reason? Would you book a room at a hotel called Messier?

william harryman said...

Yeah, if there's no bohemian coffee shop, no point going.

I was just grooving on the purdy picture.

Peace,
Bill

Unknown said...

Now I feel bad.

It is a very nice picture.

I wonder how many sentient beings we're looking at. If we figure just one in 2000 stars has an inhabitable planet. And the inhabitable planets have an average of two billion sentient beings each. That makes for a whole lot of sentient beings.

I wonder how many of them are looking at us. Of course, just our luck, it could be that the Milky Way is rather ugly and is tilted away from them in a less photogenic position. Sigh.