APOD: The Magnificent Horsehead Nebula (2010 May 13)

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Expand view Topic review: APOD: The Magnificent Horsehead Nebula (2010 May 13)

Re: APOD: The Magnificent Horsehead Nebula (2010 May 13)

by Chris Peterson » Fri Jan 21, 2011 4:15 pm

slick wrote:I know this is an old pic, but I have had someone ask something about it, and would like someone with insight to explain it for me so I can explain it to him. Here is what he said re. the explaination:

"I think they are vastly over estimating sizes.

Think about it. An object supposedly so big it takes years for light from the back side just to reach the front side.

If that were true, the light from the front side would reach us many years sooner that light from that back side that would have been in a different place in the sky at that time.

The object would appear as a long smear in the sky, not a solid object."
It would not appear as a "smear", but would be distorted if it was moving. And in fact, all objects we see do have this distortion. But it is very small- usually too small to detect. That's because the objects we view do not move very much during the time differential between when light from their near side and light from their far side reaches us. And since the objects are generally amorphous, a shift in apparent position of some structure by a fraction of a degree is not really apparent, in any case.

Re: APOD: The Magnificent Horsehead Nebula (2010 May 13)

by slick » Fri Jan 21, 2011 2:53 pm

I know this is an old pic, but I have had someone ask something about it, and would like someone with insight to explain it for me so I can explain it to him. Here is what he said re. the explaination:

"I think they are vastly over estimating sizes.

Think about it. An object supposedly so big it takes years for light from the back side just to reach the front side.

If that were true, the light from the front side would reach us many years sooner that light from that back side that would have been in a different place in the sky at that time.

The object would appear as a long smear in the sky, not a solid object."

Re: APOD: The Magnificent Horsehead Nebula (2010 May 13)

by neufer » Fri May 14, 2010 3:48 pm

Chris Peterson wrote:
johnhami wrote:By the way, why do you guys refer to a target in light years as a "mere" 100-2000 or so from us? We would never see that firsthand at these distances. Travel of just one light year is pure science fiction
Things within a few thousand light years are in our corner of the galaxy. These are typically things we can see with the naked eye, or with very modest equipment. In a universe with edges that are tens of billions of light years away, "mere" isn't a bad way to talk about a few thousand.
  • _______ Finnegans Wake

    [page 583.12] And the twillingsons, ganymede, garrymore, turn in trot and trot. But old pairaMERE goes it a gallop, a gallop.

    [page 627.5] Just a whisk brisk sly spry spink spank sprint of a thing theresoMERE, saultering.

    [page 628.16] O bitter ending! I'll slip away before they're up. They'll never see. Nor know. Nor miss me. And it's old and old it's sad and old it's sad and weary I go back to you, my cold father, my cold mad father, my cold mad feary father, till the near sight of the MERE size of him, the moyles and moyles of it, moananoaning, makes me seasilt saltsick and I rush, my only, into your arms

Re: APOD: The Magnificent Horsehead Nebula (2010 May 13)

by Chris Peterson » Fri May 14, 2010 1:20 am

johnhami wrote:By the way, why do you guys refer to a target in light years as a "mere" 100-2000 or so from us? We would never see that firsthand at these distances. Travel of just one light year is pure science fiction
Things within a few thousand light years are in our corner of the galaxy. These are typically things we can see with the naked eye, or with very modest equipment. In a universe with edges that are tens of billions of light years away, "mere" isn't a bad way to talk about a few thousand.

Re: APOD: The Magnificent Horsehead Nebula (2010 May 13)

by johnhami » Fri May 14, 2010 1:11 am

What are the odds? I kept old favorites from 1994 on a floppy disk and pulled up one today and pasted it on the screen as a desktop just for the heck of it. Yep, you guessed it (and before I saw it) - the Horsehead Nebula, today's APOD. Never in a million light years!

By the way, why do you guys refer to a target in light years as a "mere" 100-2000 or so from us? We would never see that firsthand at these distances. Travel of just one light year is pure science fiction

Re: APOD: The Magnificent Horsehead Nebula (2010 May 13)

by Astronut » Thu May 13, 2010 5:59 pm

Hofi -- Before a few up-grades ago, the Eagle Nebula tower on the left looked more like a horse head than it does now.
In the case of Space - sometimes - the more details we get, the less it looks like what we thought it looked like when we first saw it.

However, what would we see if the Hubble could see where everything started from? If the colorlessness of Space, that push's everything apart from one-another, has followed everything outward, then should'nt we be able to see what was there 'BEFORE' anything covered it up and trampled it down on its way outward??

Or how about we get a Dark Energy/Matter eraser and erase a small part of it somewhere. What would we find in that spot with the Darkness removed?? Just a thought :idea:

Re: APOD: The Magnificent Horsehead Nebula (2010 May 13)

by Chris Peterson » Thu May 13, 2010 5:51 pm

Astronut wrote:Are there actually any colorful objects that the Hubble or others have seen that look colorful on their own ??
Not really. Planets and stars are bright enough for the human eye to detect color, but that's all. Nebulas and galaxies are generally too dim to trigger human color vision. There are a handful of exceptions- very bright nebulas like Orion and the Blue Snowball that show very faint color- usually only green (the peak of human response). But most people don't even see the faint color in these objects.

To the human eye, the Universe is basically gray.

Re: APOD: The Magnificent Horsehead Nebula (2010 May 13)

by Astronut » Thu May 13, 2010 5:36 pm

Yup! I think I'll stick with my original assesment that it's "The Thing that Ate the Nebula".
That way no matter how many :b: one has had - or how much the technology has improved - the Title of it will always apply and may even improve with a few more :b: :lol: .

Are there actually any colorful objects that the Hubble or others have seen that look colorful on their own ??

Re: APOD: The Magnificent Horsehead Nebula (2010 May 13)

by Hofi » Thu May 13, 2010 4:44 pm

That's right! I think that especially the "missing" colors help to see the object through a telescope as it is named. But these gray images are just something for nerds, "normal" public would not be quite interested in it.

Looking at the constellations, it's different. I just cannot see the imaginated things behind the stars. But in my opinion, that is because a lot of the constellations were choosen willfully, not considering the stars' positions.

Re: APOD: The Magnificent Horsehead Nebula (2010 May 13)

by Chris Peterson » Thu May 13, 2010 4:31 pm

Astronut wrote:I think sometimes the ones that name these things have one toooooo many :b: while doing so :!: :lol:
Actually, most of these objects were named based on their visual appearance through the eyepiece of a telescope. In that view, everything is dim, gray, and fuzzy. Most famous objects like the Horsehead really do look a lot like their names suggest when seen that way. The "problem" is that new technology is producing these rich, colorful, incredibly high resolution images. In many cases, the forest is being lost for the trees.

Re: APOD: The Magnificent Horsehead Nebula (2010 May 13)

by Hofi » Thu May 13, 2010 4:03 pm

Astronut wrote:I have seen - on tv - when Hubble pictures have been shown, a picture similiar to this one only the horse's head was faceing to the right and it actually looked like a horse's head.
It must have been a different Nebula with a different name, which figures. I think sometimes the ones that name these things have one toooooo many :b: while doing so :!: :lol:
I think you mean the Eagle Nebula (Messier 16, NGC 6611). The Hubble image looks so:
Image

Re: APOD: The Magnificent Horsehead Nebula (2010 May 13)

by marvin the martian » Thu May 13, 2010 3:56 pm

Horse head? Nope, it's always been a ghostly headless person to me.

Re: APOD: The Magnificent Horsehead Nebula (2010 May 13)

by Chris Peterson » Thu May 13, 2010 1:00 pm

rstevenson wrote:I've always thought of it as more of a seahorse.
I always saw it as a seahorse or chess knight, until the day I saw it as a horse from behind. Since then, I've not been able to see it as anything else.

Re: APOD: The Magnificent Horsehead Nebula (2010 May 13)

by Astronut » Thu May 13, 2010 12:39 pm

Nope! no matter how you guys do it, its just not a horse head - to me!
I have seen - on tv - when Hubble pictures have been shown, a picture similiar to this one only the horse's head was faceing to the right and it actually looked like a horse's head.
It must have been a different Nebula with a different name, which figures. I think sometimes the ones that name these things have one toooooo many :b: while doing so :!: :lol:

Re: APOD: The Magnificent Horsehead Nebula (2010 May 13)

by Hofi » Thu May 13, 2010 12:11 pm

orin stepanek wrote:maybe it could just be the 'Horse Nebula'! :wink:
I'd rather say that it is also just the head of a seahorse...
I cannot see any flippers.

Re: APOD: The Magnificent Horsehead Nebula (2010 May 13)

by orin stepanek » Thu May 13, 2010 12:06 pm

maybe it could just be the 'Horse Nebula'! :wink:

Re: APOD: The Magnificent Horsehead Nebula (2010 May 13)

by Hofi » Thu May 13, 2010 12:06 pm

rstevenson wrote:I've always thought of it as more of a seahorse.
seahorse.jpg
This one fits too! Nice find!

Re: APOD: The Magnificent Horsehead Nebula (2010 May 13)

by rstevenson » Thu May 13, 2010 11:57 am

I've always thought of it as more of a seahorse.

Rob
seahorse.jpg
seahorse.jpg (14.8 KiB) Viewed 3165 times

Re: APOD: The Magnificent Horsehead Nebula (2010 May 13)

by Hofi » Thu May 13, 2010 11:50 am

neufer wrote:
  • 1) What you have as the horse's head is really the top of its mane.

    2) What you have as the horse's ass is really the back of its head.

    3) What you have as the horse's tail is really the back of its mane.
I agree! I also always saw it this way. But this overlay also fits quite well!

Re: APOD: The Magnificent Horsehead Nebula (2010 May 13)

by neufer » Thu May 13, 2010 11:34 am

Chris Peterson wrote:
Astronut wrote:From that particular angle it just does not look like a horse head to me.
hha.jpg
Based upon today's APOD I would say rather that:
  • 1) What you have as the horse's head is really the top of its mane.

    2) What you have as the horse's ass is really the back of its head.

    3) What you have as the horse's tail is really the back of its mane.

Re: APOD: The Magnificent Horsehead Nebula (2010 May 13)

by Hofi » Thu May 13, 2010 5:32 am

A really great picture!

I wonder why and how it is that the area bottom-left of the horsehead is sharper than the rest. Does anyone of you have any ideas?

Re: APOD: The Magnificent Horsehead Nebula (2010 May 13)

by Chris Peterson » Thu May 13, 2010 4:42 am

Astronut wrote:From that particular angle it just dose not look like a horse head to me.
hha.jpg
hha.jpg (19.54 KiB) Viewed 3223 times

Re: APOD: The Magnificent Horsehead Nebula (2010 May 13)

by Astronut » Thu May 13, 2010 4:35 am

OH - WOW!! a movie advertisement. The thing that ate the Nebula. Now playing in a Galaxy near you.

From that particular angle it just dose not look like a horse head to me.

APOD: The Magnificent Horsehead Nebula (2010 May 13)

by APOD Robot » Thu May 13, 2010 3:51 am

Image The Magnificent Horsehead Nebula

Explanation: Sculpted by stellar winds and radiation, a magnificent interstellar dust cloud by chance has assumed this recognizable shape. Fittingly named the Horsehead Nebula, it is some 1,500 light-years distant, embedded in the vast Orion cloud complex. About five light-years "tall", the dark cloud is cataloged as Barnard 33 and is visible only because its obscuring dust is silhouetted against the glowing red emission nebula IC 434. Stars are forming within the dark cloud. Contrasting blue reflection nebula NGC 2023, surrounding a hot, young star, is at the lower left. The gorgeous color image combines both narrowband and broadband images recorded using three different telescopes.

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