Lois & Clark Forums Forums General Discussion Off Topic Cool astronomical picture (or at least I think so...)

I know, I know, I keep posting all these astronomical pictures and tidbits here. Oh, but this one is cool! At least I really think so!

Really cool starscape and cloudscape

Sorry I'm only posting a link, but I'm worried that I may not be allowed to directly hotlink this image!

As you can see if you click on the link, this picture is called 'A Protected Night Sky Over Flagstaff' (which tells you where the picture was taken, too). 'Protected' in this case means protected against light pollution - no unnecessary street lights are allowed!

Not all night skies are protected against light pollution, to be sure.


A light polluted sky.

(The fact that almost no artifcial lights are allowed over Flagstaff means that the color of the striking mountain-hugging cloud formation reflects the general color of the unspoilt sky, not the color of street lights and neon signs.)

Look at the first picture again, the one you'll have to click on the link to see. In a way, the most amazing-looking thing in it is the fantastic lenticular cloud hugging the mountain! A comment posted on the picture said that the cloud looked like an humongous alien spaceship emerging from behind the mountains!!



(As for what a lenticular cloud really is and how they form, why don't you click on the link you can find if you open that first picture?)

Above the cloud, you see the beauty of the Milky Way stretching from lower left to the upper right across the image. The Milky Way is, quite simply, our own flat disc-shaped galaxy seen from inside and, literally, seen from the side. This is another picture of the Milky Way, seen from our earthbound sideways vantage point:

Road on Earth and Milky Way

Here is another galaxy altogether, NGC 4013, which is also seen from the side:

Edge-on galaxy NGC 4013

See the very dark 'band' running right along the entire galaxy? That's the so-called galactic dust band. The 'dust' is made of tiny particles of, for the most part, ice-covered miniscule grains of coal, billions and billions and billions of them. When these grains gather in sufficient numbers, they start slowly collapsing under their own weight, sometimes giving rise to the birth of new stars. (Stars are born inside thick dark clouds of hydrogen gas and 'space dust'.)

Take a look at the Milky Way pictures again. You see those dark 'blotches' inside the bright 'path' of the Milky Way? Those are indeed dark 'dust clouds' (or as they are often called, molecular clouds) and some of them are indeed giving birth to new stars.

Some new-born stars are extremely hot. Such stars emit copious ultraviolet light. When ultraviolet light hits a hydrogen atom, it will knock the electron into a higher orbit around the proton. After a while, however, the electron will 'fall down' into a lower orbit again, and when it does so, it will emit a specific wavelength of red light. Therefore, extremely hot young stars are often surrounded by glowing red clouds of hydrogen, which glow red because all those trillions and trillions of electrons which are simultanelously 'falling down' after they were 'excited' (that is, 'lifted up') by being struck by an ultraviolet photon.

In the first picture I posted a link to here, you can see one of the most famous 'emission nebulae' - clouds of glowing red hydrogen - in the sky. It is called the North America Nebula. Cool, eh? And it really does look a bit like North America, too. In the first picture, you can see the North America Nebula towards the upper right, in the two o'clock position. Here is a better picture of the North America Nebula:

The North America Nebula

It sure looks like North America, doesn't it? Surely you can see 'The Bay of Mexico'? And to the right of the North America Nebula you find The Pelican Nebula. Can you see the Pelican's neck, beak and dark eye? The pelican is facing left, in case you are wondering.

Anyway. The North America Nebula and the Pelican Nebula are really one and the same glowing gas cloud, seemingly cut in two by a really thick dust lane. The star that causes all this hydrogen to glow red is situated behind this dark curtain, but it is nevertheless faintly visible. Can you locate the star that would be equivalent to Miami if the North America Nebula was North America itself?

If you find 'Miami', try to find a faint red star to the right and slightly below 'Miami'. To the right of this faint red star there is another faint star, also somewhat reddish. Can you find it? Okay. Because scientists believe that this last star is the culprit, the star responsible for making many many cubic light years of hydrogen gas glow red. This faint reddish star is really blindingly blue-white, but it looks so faint and reddish because the dark dust swallows up so much of its visible light. The star is estimated to be as a hot as about 40,000 degrees Kelvin, almost seven times as hot as the Sun.

Where does all the dark dust come from, by the way? Astronomers say that stars like the Sun make a huge amount of dust as they prepare to die, and then the spew this dust out into the cosmos.



A dusty dying star, sending out 'searchlight beams' through openings in a thick dusty torus ('donut') surrounding it.

Anyway. Wowzers, you know?

Ann

Wowzers is right!!! I love astronomy!! Thanks for posting those Ann. They're beautfiul.

This stuff is great, Ann! I love astronomy. I took a lot of it in my first round through college, and it still never ceases to amaze me. That picture of all the stars over Flagstaff is amazing. It makes me feel like we're all so very small and insignificant in the grand scheme of it all (which we really are).

Thanks for sharing!!