Stephen Speicher

Spectacular Hubble image of a spiral galaxy

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This newly-released detailed image of the spiral galaxy NGC 5457 (Messier object M101), is spectacular beyond belief!

xlarge_web.jpg

Affectionately known as the Pinwheel galaxy, M101 encompasses some one trillion (!) stars spread across a span of 170,000 light-years, some 25 million light-years from us.

The displayed image is only 289.8 kB in size. Here you can download a 9.48MB or a 58.7MB image. Suitable for framing, to say the least!

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Affectionately known as the Pinwheel galaxy, M101 encompasses some one trillion (!) stars spread across a span of 170,000 light-years, some 25 million light-years from us.

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Thanks, Stephen. I love pictures like that. I've been thinking for several weeks now where to go on vacation, and you've provided me with the perfect location. I'll email you some Milky Way pictures when I get there. I'm not too worried about getting there, it's the trip home that's a bummer!!

;)

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I've been thinking for several weeks now where to go on vacation, and you've provided me with the perfect location.

If you are planning your vacation in July, that would be perfect timing. July is an off-season for M101. ;)

I'll email you some Milky Way pictures when I get there.  I'm not too worried about getting there, it's the trip home that's a bummer!!

Some say if you travel fast-enough, you can get back even before you started!

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[...] M101 encompasses some one trillion (!) stars [...]

I remember hearing Carl Sagan mention on his miniseries Cosmos (some of which I like a great deal, and especially overall his "sense of wonder" at the universe) that there were more stars than grains of sand on the earth. That's just staggering. Have you heard that comparison, and if so, do you know how such an estimation could be made? Off the cuff, I figured you could form some upper estimate of the number of sand grains by taking some average volume of a grain and computing how many would fit in a, say, mile thick shell over the earth, and comparing that number to the estimated number of stars in the observable universe.

I realize of course that in Alex's hypothesis, there are no limits to the number of entities in the universe, making the question moot, but I'm speaking now of that part of the universe that's observable to date, which I assume is what Sagan was talking about.

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I remember hearing Carl Sagan mention on his miniseries Cosmos (some of which I like a great deal, and especially overall his "sense of wonder" at the universe) that there were more stars than grains of sand on the earth. That's just staggering. Have you heard that comparison, and if so, do you know how such an estimation could be made?

It is difficult to complete a mathematics or physics curriculum without that problem appearing at some point. I've never seen a formal paper in a technical journal, but the internet abounds with a multitude of such calculations. Here is one.

More interesting, however, is how millenium ago Archimedes estimated the grains of sand on a beach, and more. See Archimedes' The Sand Reckoner.

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Looking at this image, I started to ask myself what some of those yellow (artificially so?) flecks, mainly scattered about on the right half of the frame, might be. Are they also galaxies?

Then I spotted one at ten-o'clock what is obviously yet another spiral galaxy, presumably in the background. So re-point Hubble, zoom in, and there is yet another photo like this one.

I'm amazed I don't bump into things more often when I away from city lights and can see the night sky. In such situations, I'm incessantly looking up ...

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It is difficult to complete a mathematics or physics curriculum without that problem appearing at some point. I've never seen a formal paper in a technical journal, but the internet abounds with a multitude of such calculations. Here is one.

More interesting, however, is how millenium ago Archimedes estimated the grains of sand on a beach, and more. See Archimedes' The Sand Reckoner.

Thanks for the links. re: the Archimedes problem, fascinating. I'd never heard of it before. Reading the translation it's apparent what an incredible genius that he was (in addition to all the other evidence to that effect.)

I'm confused about something though - on this page they describe the notation that Archimedes used:

http://www.calstatela.edu/faculty/hmendel/...ranslationNotes

particularly his subscripted ranking system. They say:

"In the notes a number in his system is given with its rank as a subscript. 1324 (sub 7) is 1324 of the seventh rank, i.e., 1324 * 10^49-1 or more in our notation 1.324 *10^51."

I still don't get the system. My first thought is that the rank is an index into the table that they give, but beyond 8, each increase is a power of 10, and whether you count from 0 or from 1, it still doesn't remotely get rank 7 -> 10^48. My second thought is that the rank represents powers of myriads (4 digits = 10000), but that would give 10^28, so that doesn't begin to match either. Can you elaborate on this?

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If you are planning your vacation in July, that would be perfect timing. July is an off-season for M101.  :D

Some say if you travel fast-enough, you can get back even before you started!

Yea, but as I've learned from previous posts, it's not the getting there that hurts, it's the starting and stopping (acceleration/deceleration) when all the bad things happen!! ;)

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Yea, but as I've learned from previous posts, it's not the getting there that hurts, it's the starting and stopping (acceleration/deceleration) when all the bad things happen!! ;)

It's not even that - it's that not all of you stops at the same time.

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It's not even that - it's that not all of you stops at the same time.

Maybe a deep 15-month sleep in a tank of water would fix that :D (that is an interesting question, just how would you manage a possible year-long voyage to another planet?)

I as well love pictures of this kind (I am a Physics Major!); makes me want to get back to running my computer on the SETI program.

I downloaded the 50+meg image and it keeps locking up whatever application I try to open it with though ;)

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It's not even that - it's that not all of you stops at the same time.

Which part stops first?

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Which part stops first?

If you were to accelerate or decelerate too quickly wouldn't your brain slosh around in your skull? That's how concussions are caused at least.

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You guys are nuts! ;)

I like to go to the Hubble site every once and a while to look at the pictures. I try to conceive of the size of whatever I'm looking at, but it is too grand for my unschooled brain. Do those of you who have studied the physics and understand what a light-year is really have a grip on what it means to say that something is 170,000 light-years wide?

It's funny that people make up things for something to stand in awe of (religion). All I do is look at our magnificent universe through pictures like those from Hubble, or even the pictures from the SOHO site of our dynamic sun changing its face every day and I've found all the awe I can handle. How could anyone want anything more than to be a part of all of this? Nothing could be grander than to have a mind that makes up for our puny senses, the kind of mind that enables us to see something like this picture.

Is this galaxy what our Milky Way would look like if seen from this perspective?

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Is this galaxy what our Milky Way would look like if seen from this perspective?

For a bird's eye view, check this out.

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Is this galaxy what our Milky Way would look like if seen from this perspective?

If you look up at the sky when it's really dark and no city lights, you'll see a thin band of haze. That's the Milky Way.

Also, check this: http://cassfos02.ucsd.edu/public/tutorial/MW.html

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You guys are nuts! ;)

I like to go to the Hubble site every once and a while to look at the pictures.  I try to conceive of the size of whatever I'm looking at, but it is too grand for my unschooled brain.  Do those of you who have studied the physics and understand what a light-year is really have a grip on what it means to say that something is 170,000 light-years wide?

Yea. It means the chances of finding intelligent life in the universe outside of earth are extremely small. It also means that, presently, that galaxy may not be there any more because the light coming from the galaxy is several hundred million years old.

It's funny that people make up things for something to stand in awe of (religion).  All I do is look at our magnificent universe through pictures like those from Hubble, or even the pictures from the SOHO site of our dynamic sun changing its face every day and I've found all the awe I can handle.  How could anyone want anything more than to be a part of all of this?  Nothing could be grander than to have a mind that makes up for our puny senses, the kind of mind that enables us to see something like this picture.

Makes life enjoyable, for sure.

Is this galaxy what our Milky Way would look like if seen from this perspective?

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If you were to accelerate or decelerate too quickly wouldn't your brain slosh around in your skull?  That's how concussions are caused at least.

If I was smart enough to build a spaceship that could travel at the speed of light, I'd be smart enough to have a mechanism that would control my accleration at a safe rate. ;)

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Thanks for the links. re: the Archimedes problem, fascinating. I'd never heard of it before. Reading the translation it's apparent what an incredible genius that he was (in addition to all the other evidence to that effect.)

I'm confused about something though - on this page they describe the notation that Archimedes used:

http://www.calstatela.edu/faculty/hmendel/...ranslationNotes

particularly his subscripted ranking system. They say:

"In the notes a number in his system is given with its rank as a subscript. 1324 (sub 7) is 1324 of the seventh rank, i.e., 1324 * 10^49-1 or more in our notation 1.324 *10^51."

I still don't get the system. My first thought is that the rank is an index into the table that they give, but beyond 8, each increase is a power of 10, and whether you count from 0 or from 1, it still doesn't remotely get rank 7 -> 10^48.  My second thought is that the rank represents powers of myriads (4 digits = 10000), but that would give 10^28, so that doesn't begin to match either. Can you elaborate on this?

It depends upon what that translator meant by "rank." It's a little confusing, but remember this was Ancient Greece, before the decimal system. (In fact, the great mathematician Gauss once lamented the fact that Archimedes came so close but failed to see the decimal system in this work that went so far beyond the scope of numbers the Greek system was capable of representing.)

For his purposes in The Sand Reckoner, Archimedes used a myriad (10,000) of myriads as a first unit, i.e., the octad 100000000 (10^8) was first order. The second order ran from 10^8 to 10^16, and so on to the 10^8th order, (10^8)^(10^8). This last as a number Archimedes then called the first period, and the scheme repeated for 10^8th periods.

So, the 1324(rank 7) by that translator is really 1324(order 6), which is 1324*(10^8)^6, or 1324^(10^48), which in more usual scientific notation is 1.324*(10^51).

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Which part stops first?

In order to accelerate/decelerate an object so that the particles of which it is composed keep a fixed proper distance between them (i.e., that the object does not pull apart or squish), a different acceleration/deceleration would have to be applied along the length of the object. In fact, in relativity there is such a concept, which is known as Born rigid motion. Ordinarily acceleration is not instantaneous throughout an object (it takes time to transmit forces), and with the sufficient acceleration/deceleration of an object the internal forces holding it together can be overcome, and the object can literally be ripped apart or squished together.

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I like to go to the Hubble site every once and a while to look at the pictures.  I try to conceive of the size of whatever I'm looking at, but it is too grand for my unschooled brain.  Do those of you who have studied the physics and understand what a light-year is really have a grip on what it means to say that something is 170,000 light-years wide?

Sure. "Conceptualization is a method of expanding man's consciousness by reducing the number of its content's units—a systematic means to an unlimited integration of cognitive data." (ITOE, p. 64). If you work with the units then the process of reduction from the greater to the smaller (light-years to inches) is an abstractly grasped process that becomes automated and therefore connected to the perceptual world. It is not direct perception, but it is grasped abstractly in a very meaningful way.

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I've had a partial picture of that galaxy running as part of my screensaver for about a year now.

You can get your hands on lots more, right here.

These are my personal favorites:

v838 Monocerotis Light Echo

p0410ab.jpg

Spiral M646

p0404ab.jpg

And this one's not from hubble heritage:

M16 Eagle Nebula -- the image, is called "Pillars of Creation"

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In order to accelerate/decelerate an object so that the particles of which it is composed keep a fixed proper distance between them (i.e., that the object does not pull apart or squish), a different acceleration/deceleration would have to be applied along the length of the object. In fact, in relativity there is such a concept, which is known as Born rigid motion. Ordinarily acceleration is not instantaneous throughout an object (it takes time to transmit forces), and with the sufficient acceleration/deceleration of an object the internal forces holding it together can be overcome, and the object can literally be ripped apart or squished together.

I don't remember Captain Kirk having that problem!! ;)

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For his purposes in The Sand Reckoner, Archimedes used a myriad (10,000) of myriads as a first unit, i.e., the octad 100000000 (10^8) was first order. The second order ran from 10^8 to 10^16, and so on to the 10^8th order, (10^8)^(10^8). This last as a number Archimedes then called the first period, and the scheme repeated for 10^8th periods.

So, the 1324(rank 7) by that translator is really 1324(order 6), which is 1324*(10^8)^6, or 1324^(10^48), which in more usual scientific notation is 1.324*(10^51).

Thanks Stephen, that clarifies things to a degree. So in the translation, the rank means a factor of (10^8)^(rank-1).

In the above, don't you mean "and so on to the 8th order, (10^8)^8"? (10^8)^(10^8) would be about a hundred million digits expanded out. ;)

I can see what Gauss meant. It's really strange that Archimedes didn't discover and use the decimal system. His ranking system could be considered an exponential base system as well, except that it's base "octad", 10^8, rather than base 10 - going from 10^8 to 10^16 being analogous to (10^1) to (10^2) for 10..100, etc. I don't recall if the Greeks had the concept of zero - if they didn't, then missing that would seem to be a key issue in not discovering a simpler base system.

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