Starship Asterisk*

by **geckzilla** » Wed Aug 19, 2015 7:47 pm

Ghoulardi wrote:
Claudio wrote:To explain the small mistake we are discussing for who is not Italian, Apuan Alps are actually here:
https://goo.gl/maps/n3USf
....just south of Parma, a suburb of Cleveland

Link takes me to Italy. It was nothing like Olive Garden.

by **Ghoulardi** » Wed Aug 19, 2015 4:07 pm

Claudio wrote:To explain the small mistake we are discussing for who is not Italian, Apuan Alps are actually here:
https://goo.gl/maps/n3USf

....just south of Parma, a suburb of Cleveland

by **Claudio** » Wed Aug 19, 2015 1:30 pm

To explain the small mistake we are discussing for who is not Italian, Apuan Alps are actually here:
https://goo.gl/maps/n3USf

Even if the Apuan mountains are part of the Appennini range, they are called "Alps" because the landscapes resembles the ones of the real Alps. There are some places known to have good skies for stargazing, but are more known for the marble quarries (Michelangelo used to choose the marble for his sculpture in the quarries of Carrara) and the great landscapes.

by **Alessandro Gardini** » Wed Aug 19, 2015 7:14 am

Please notice that, as explained in the link to the author, Andromeda is rising over the Apuan Alps, not the Alps. Apuan Alps are part of the Apennine Mountains and are renowned for the famous Carrara marble.

by **Claudio** » Tue Aug 18, 2015 7:17 pm

There is a small error in the caption of the picture: the picture was taken on the Apuan Alps, which are actually NOT the real Alps but part of the Appennini Mountain chain. Nevertheless, great picture!

by **andreadomenici** » Tue Aug 18, 2015 5:37 pm

The picture was not taken from the Alps but from the Alpi Apuane. This is a small mountain range which belongs to the Appennine mountains, but it is called "Alpi" because of its peculiar morphology. It is part of the provinces of Lucca and Massa-Carrara, in Tuscany.

Great picture at any rate. Thank you, NASA!

Andrea Domenici

by **chuckster** » Tue Aug 18, 2015 4:25 pm

Besides not being able to see the full size and magnificence of Andromeda in visible light from Earth with your own eyes, another thing that gets me about galaxies in general, especially the ones tipped enough to our line of sight to see the whole thing, is that the light from that far rim may be (say) 150,000 yrs older than the light from the near rim, and all along the sides of the elliptical view, the age of the light is different depending on its distance. There's an age gradient throughout the disc, relative to Earth, along our line of sight. Pictures of colliding galaxies are incredible, but what parts of each galaxy don't know they're in collision yet, from our distant viewpoint ? Even locally, the events of the collision (star formation, black holes combining, etc) are far enough from each other to make it impossible for a single observer to see the whole thing in real time. The mind boggles. Even a full-on flat face view has an age gradient in its light. For us, and for the stars and gas and dust on-scene, there are delays as gravity waves orchestrate the collision, and new stars form, etc, and it all gets reported to us, after light travel time delays, and out of sequence, because of the distances involved.

by **Guest** » Tue Aug 18, 2015 2:09 pm

Boomer12k wrote: ........
Now...an ELECTRON has mass...and yet...travels at the same speed... ALL electro-magnetic radiation travels at the same speed...so...the question is, WHY can an electron with a mass, travel at the same speed of light, which supposedly has no mass?

I guess as an OBJECT in space...it does not age, as it does not appear to deteriorate, but still takes 100,000 EARTH years to cross the galaxy, or 2.2 million from Andromeda, or 11mly from other galaxies. As a WAVE, I wonder at how it stays the same, as it should dissipate some as it goes outward, and should "widen" as with other waves. Radio waves for example dissipate around 1.5-2 ly away from us...NO ONE is watching Lucy 60 ly out...the signal has long dissipated to the point of being unrecognizable, and blends with the background noise. You need a "tight" beam I guess, and regular radio, television, just does not do that. But Light does not seem to widen, nor dissipate as an energy wave. It is an odd thing. And yet, a projection of light WIDENS from the source, and it does get dimmer with distance.
There are so many illusions with light, it is hard to get past the apparencies, and quandaries.

I still say it is quite the illusion.
:---[===] *

Boomer:
electrons do NOT travel at the speed of light, nor does electric current.
Light, radio, or any EMRs do not decay or dissipate with distance. (perhaps for the very reason that, in a photon's reference frame, no time has elapsed even if it crossed the 14 billion ly diameter of the known universe). But from a point source, radiant waves get more widely separated, as they are not parallel. Sunbeams on earth are nearly parallel for our purposes, but are not absolutely.
BTW, distant simultaneity is the illusion. For the 2 million year old photon we were discussing, to it the universe looks exactly the same at its emission and absorption 2 million years later; only its position has changed. Only what's in a observer's light cone matters. The simultaneous hyperplane/the 'hypersurface of the present', is purely an abstraction.

by **tomatoherd** » Tue Aug 18, 2015 2:09 pm

Boomer12k wrote: ........
Now...an ELECTRON has mass...and yet...travels at the same speed... ALL electro-magnetic radiation travels at the same speed...so...the question is, WHY can an electron with a mass, travel at the same speed of light, which supposedly has no mass?

I guess as an OBJECT in space...it does not age, as it does not appear to deteriorate, but still takes 100,000 EARTH years to cross the galaxy, or 2.2 million from Andromeda, or 11mly from other galaxies. As a WAVE, I wonder at how it stays the same, as it should dissipate some as it goes outward, and should "widen" as with other waves. Radio waves for example dissipate around 1.5-2 ly away from us...NO ONE is watching Lucy 60 ly out...the signal has long dissipated to the point of being unrecognizable, and blends with the background noise. You need a "tight" beam I guess, and regular radio, television, just does not do that. But Light does not seem to widen, nor dissipate as an energy wave. It is an odd thing. And yet, a projection of light WIDENS from the source, and it does get dimmer with distance.
There are so many illusions with light, it is hard to get past the apparencies, and quandaries.

I still say it is quite the illusion.
:---[===] *

Boomer:
electrons do NOT travel at the speed of light, nor does electric current.
Light, radio, or any EMRs do not decay or dissipate with distance. (perhaps for the very reason that, in a photon's reference frame, no time has elapsed even if it crossed the 14 billion ly diameter of the known universe). But from a point source, radiant waves get more widely separated, as they are not parallel. Sunbeams on earth are nearly parallel for our purposes, but are not absolutely.
BTW, distant simultaneity is the illusion. For the 2 million year old photon we were discussing, to it the universe looks exactly the same at its emission and absorption 2 million years later; only its position has changed. Only what's in a observer's light cone matters. The simultaneous hyperplane/the 'hypersurface of the present', is purely an abstraction.

by **Boomer12k** » Tue Aug 18, 2015 2:00 pm

wbd wrote:Never seen Andromeda, but it is my #1 on my bucket list of deep sky targets.
I live right down the 'bottom' of Australia, so M31 is below our northern horizon, so I always love seeing pictures of our 'cosmic neighbor'.

I have ALWAYS want to see...the MAGELLANIC CLOUDS...but cannot...being in Oregon, USA...and always appreciate a good image of them....so we are even?

:---[===] *

by **bystander** » Tue Aug 18, 2015 1:51 pm

paragkulkarni wrote:
Tszabeau wrote:There appears to be another galaxy, that looks to be even further away from us than Andromeda, just above Andromeda. Would not that galaxy's light be "older"?
M32 ?

bystander wrote:
Tszabeau wrote:There appears to be another galaxy, that looks to be even further away from us than Andromeda, just above Andromeda. Would not that galaxy's light be "older"?
Non Professional wrote:Is that other one M32? It's fairly close to M31, isn't it?
That would be M110. M32 is also visible in the high def image. It looks like a fuzzy star below and to the right of M31.

by **paragkulkarni** » Tue Aug 18, 2015 1:47 pm

Tszabeau wrote:There appears to be another galaxy, that looks to be even further away from us than Andromeda, just above Andromeda. Would not that galaxy's light be "older"?

M32 ?

by **wbd** » Tue Aug 18, 2015 7:30 am

Never seen Andromeda, but it is my #1 on my bucket list of deep sky targets.
I live right down the 'bottom' of Australia, so M31 is below our northern horizon, so I always love seeing pictures of our 'cosmic neighbor'.

by **Joe Stieber** » Tue Aug 18, 2015 3:19 am

Chris Peterson wrote:
ronreefman wrote:Am I seeing things? On my computer screen the photograph is 10" from left to right and Andromeda, although faint, appears to be 1.5" of the 10" total. The center of the galaxy is easy and bright, but is that 1.5" disk the actual size on Andromeda in our sky if we could see it more clearly? Or am I just seeing things?
The image is 11° across (not arcseconds, which is the symbol you used). The average scale is 9.9 arcseconds per pixel (on the full sized image). That makes the bright core about 1/4° wide, which I think is pretty close to what we see visually under most conditions. The full galaxy spans a little over 2° in this short exposure. That's also typical of images, although a much longer exposure will show the galaxy extending to about 3°.

So yes, if our eyes were more sensitive we'd see M31 extending 4-6 Moon widths, instead of the more typical 0.5-1 Moon widths from the bright core.

I suspect that ronreefman was measuring his screen in inches (alas, the quote mark is used for both inches and seconds). In any case, if we take ron's ratio of 1.5"/10" and multiply it by Chris' 11-degree width of the picture, then the Andromeda Galaxy is about 1.7 degrees across. I measured it on-screen and compared it to star spacing on a SkyTools chart and got a width of 1.75 degrees, fairly close to ron's measurement. I also measured the core at 0.2 degrees (note: the measured edges of the galaxy and the core are somewhat indefinite).

As far as the visual appearance goes, on the morning of 13-August-2015, I was watching the Perseid meteor shower from the New Jersey Pinelands. The sky was pretty good (for NJ) with billowing Milky Way. At 3 am EDT, M31 was about 75 degrees altitude and easily visible to the unaided eye with direct vision. With careful inspection and averted vision, I could see that the length of M31 was about half to two-thirds the 2.3 degree spacing between nearby Nu and 32 Andromedae, or 1.2 to 1.5 degrees wide (approaching three moon diameters). With 16x70 binoculars, M31 was about two-thirds of the 4-degree field of the binoculars (however, because of peripheral extinction, the field probably looks to be about 3.5 degrees). Using the lesser field size, that would make M31 about 2.3 degrees wide in the binoculars (about 4.5 moon diameters). Although nice, the sky wasn't dark enough to allow the nearby Triangulum Galaxy (M33) to be seen with unaided eyes (not surprising for NJ).

by **Boomer12k** » Tue Aug 18, 2015 12:30 am

We are not SETTING....the Earth is not setting....

The VIEW is rising...objects in the view are "rising"....to our perspective.

:---[===] *

by **Boomer12k** » Tue Aug 18, 2015 12:27 am

Chris Peterson wrote:
ronreefman wrote:Am I seeing things? On my computer screen the photograph is 10" from left to right and Andromeda, although faint, appears to be 1.5" of the 10" total. The center of the galaxy is easy and bright, but is that 1.5" disk the actual size on Andromeda in our sky if we could see it more clearly? Or am I just seeing things?
The image is 11° across (not arcseconds, which is the symbol you used). The average scale is 9.9 arcseconds per pixel (on the full sized image). That makes the bright core about 1/4° wide, which I think is pretty close to what we see visually under most conditions. The full galaxy spans a little over 2° in this short exposure. That's also typical of images, although a much longer exposure will show the galaxy extending to about 3°.

So yes, if our eyes were more sensitive we'd see M31 extending 4-6 Moon widths, instead of the more typical 0.5-1 Moon widths from the bright core.

AndromedaAlps_Dunchi_4677-Moon.jpg

Now THAT is what I was asking for...THANKS, CHRIS!!!!

:---[===] *

by **Boomer12k** » Tue Aug 18, 2015 12:26 am

A Photon maybe a particle...but LIGHT is a WAVE, I guess a wave of these particles,....a Massless Wave, of a massless particle, I guess, as it has a constant speed in a vacuum, it takes time to cross space...there IS no "instant transmission"...GOKU does that in Dragonball Z...

That is THOUGHT. As a thought can picture itself some place instantly. But thought is a BRAINWAVE, and the brainwave is electro-magnetic, and is really subject to the same speed limits...so, just because I can think of being on the other side of the galaxy...does not mean it would be instantaneous. It takes time for even a WAVE to go somewhere. It does not instantly leave and arrive. I suppose to cross the space of your bedroom it is a split trillionth of a nanosecond...but is still time... AGE is not really a factor for the Photon or Light wave, it would seem. It is MORE just an Energy, not a particle, but sometimes acts, or is seen to act, as one.
Now...an ELECTRON has mass...and yet...travels at the same speed...

ALL electro-magnetic radiation travels at the same speed...so...the question is, WHY can an electron with a mass, travel at the same speed of light, which supposedly has no mass?
My guess...it has to do with ENERGY...it IS energy...an Energy...I work with Emotional Charge...Emotion Energy...

I guess as an OBJECT in space...it does not age, as it does not appear to deteriorate, but still takes 100,000 EARTH years to cross the galaxy, or 2.2 million from Andromeda, or 11mly from other galaxies. As a WAVE, I wonder at how it stays the same, as it should dissipate some as it goes outward, and should "widen" as with other waves. Radio waves for example dissipate around 1.5-2 ly away from us...NO ONE is watching Lucy 60 ly out...the signal has long dissipated to the point of being unrecognizable, and blends with the background noise. You need a "tight" beam I guess, and regular radio, television, just does not do that. But Light does not seem to widen, nor dissipate as an energy wave. It is an odd thing. And yet, a projection of light WIDENS from the source, and it does get dimmer with distance...inverse square law. Yet, with sensitive enough instruments we detect light from 13.8 BILLION LY out there...AMAZING.
PLUS, they say, and show that TIME slows as you near the S.O.L...and STOPS at the speed of light...so a photon making up light, and traveling at that speed....WE observe time for it to stop....
And AS a photon takes A MILLION YEARS to leave the center of even our humble Sun...it is actually A MILLION YEARS OLDER LIGHT!!!!! 3.2my, depending on the star, in the Andromeda Galaxy.

There are so many illusions with light, it is hard to get past the apparencies, and quandaries.

AND YET...Our Esteemed Mr. Peterson, has pointed out to me....IT IS CAPTURED TONIGHT...NOW...it is NOT 2.2 million year old light...because it was captured tonight, now....It is what is happening, now.

I still say it is quite the illusion.
:---[===] *

by **Chris Peterson** » Tue Aug 18, 2015 12:07 am

ronreefman wrote:Am I seeing things? On my computer screen the photograph is 10" from left to right and Andromeda, although faint, appears to be 1.5" of the 10" total. The center of the galaxy is easy and bright, but is that 1.5" disk the actual size on Andromeda in our sky if we could see it more clearly? Or am I just seeing things?

The image is 11° across (not arcseconds, which is the symbol you used). The average scale is 9.9 arcseconds per pixel (on the full sized image). That makes the bright core about 1/4° wide, which I think is pretty close to what we see visually under most conditions. The full galaxy spans a little over 2° in this short exposure. That's also typical of images, although a much longer exposure will show the galaxy extending to about 3°.

So yes, if our eyes were more sensitive we'd see M31 extending 4-6 Moon widths, instead of the more typical 0.5-1 Moon widths from the bright core.

by **ronreefman** » Mon Aug 17, 2015 11:35 pm

Am I seeing things? On my computer screen the photograph is 10" from left to right and Andromeda, although faint, appears to be 1.5" of the 10" total. The center of the galaxy is easy and bright, but is that 1.5" disk the actual size on Andromeda in our sky if we could see it more clearly? Or am I just seeing things?

by **Boomer12k** » Mon Aug 17, 2015 11:32 pm

chuckster wrote:
Boomer12k wrote:OH....THAT IS SOOOOOOOO COOOOOOOOL!!!!!!!!!!!

Could someone put a FULL MOON off to the side of it for comparison????

:---[===] *
That's what gets me about Andromeda. On APOD, the writer(s) always refer to "gorgeous Grand Design island universes", and, in telescopic, spectrum-enhanced images, Andromeda has all the galactic splendor the heart could wish for. AND YET, even though it's a couple moon-diameters wide in Earth's sky, we get squat. Binoculars show a smudge. Only two million ly away, relatively huge in our sky, and we still get squat. Damn my retinas !

I know. Even with 10" Meade and Deep Sky Imager I get a lousy image of only the middle area, I guess, and not well focused. I get a better image of M51....go figure.

:---[===] *

by **tomatoherd** » Mon Aug 17, 2015 7:43 pm

Dad is watching wrote:
I thought I understood relativity theory that states that the speed of light was the same for all observers. I assume that includes the photon itself. So how can a photon be created and destroyed in the same instant and cross two million light years in that instant? That is that the origin of its creation and the destination of its destruction be separated by 2 million light years. I always figured that Maxwell, Einstein, Feynman, etc, didn't have a complete understanding or equations to properly model light. But instantaneous transmission seems to be a little too far out there.

Also, just because we are talking about light and photons. If a photon is traveling at light speed. And anything traveling at light speed has infinite mass. Then why don't light bulbs blow up when you turn them on? Of course, I know they don't, but it always struck me as weird...

At the speed of light, there is infinite time dilation. So the 'instantaneous' is only from the reference frame of the photon, not us. If a sentient being dies, and then could be reanimated the next day, chances are he would feel like he went to sleep and was immediately reawakened. Barring an independent consciousness / "soul", he might feel just the same immediacy if the lapse were 2 million years.
Only particles possessing mass to begin with undergo mass increase w/ relativistic velocities, not massless particles.

by **chuckster** » Mon Aug 17, 2015 6:23 pm

Boomer12k wrote:OH....THAT IS SOOOOOOOO COOOOOOOOL!!!!!!!!!!!

Could someone put a FULL MOON off to the side of it for comparison????

:---[===] *

That's what gets me about Andromeda. On APOD, the writer(s) always refer to "gorgeous Grand Design island universes", and, in telescopic, spectrum-enhanced images, Andromeda has all the galactic splendor the heart could wish for. AND YET, even though it's a couple moon-diameters wide in Earth's sky, we get squat. Binoculars show a smudge. Only two million ly away, relatively huge in our sky, and we still get squat. Damn my retinas !

by **Dad is watching** » Mon Aug 17, 2015 6:13 pm

Chris Peterson wrote:
tomatoherd wrote:Yes, I know what the editor means by "the oldest light you will ever see..." But all light is the same age: the photons, going the speed of light, do not 'experience' time in transit: no time elapses at all for them. In their framework,their production/existence when an electron of an atom in a star in Andromeda falls to a lower level an emits a photon, to the absorption on our retinas by same process in reverse, both are instantaneous.
But, theorists aside, who really cares what sort of time a photon "experiences" in its reference frame? In our frame, which is clearly what's under consideration here, a photon has a finite lifetime, marked by a specific time of creation and a specific time of destruction. It is physically correct to recognize that we record photons that were created at different times, and hard to find fault with calling those created earlier "older".

I thought I understood relativity theory that states that the speed of light was the same for all observers. I assume that includes the photon itself. So how can a photon be created and destroyed in the same instant and cross two million light years in that instant? That is that the origin of its creation and the destination of its destruction be separated by 2 million light years. I always figured that Maxwell, Einstein, Feynman, etc, didn't have a complete understanding or equations to properly model light. But instantaneous transmission seems to be a little too far out there.

Also, just because we are talking about light and photons. If a photon is traveling at light speed. And anything traveling at light speed has infinite mass. Then why don't light bulbs blow up when you turn them on? Of course, I know they don't, but it always struck me as weird...

by **Ron-Astro Pharmacist** » Mon Aug 17, 2015 5:55 pm

I might prefer to think the Alps are setting but that's just my perspective from a slightly askew frame of reference.

The idea that we continue to speak in terms that the stars and galaxies move is somewhat perplexing but so are many things in our figures of speech.

I suppose it's a bit clunky to say, "As the Earth rotates and proceeds in its orbit…"but, someday, that would be less esoteric - though most people really do know this. What's a better term for a socially accepted term of something what not in tune with modern practice?

Near a whole "lb" for your thoughts?

by **Chris Peterson** » Mon Aug 17, 2015 5:00 pm

Tszabeau wrote:I thought the implication was that this shot was not taken with a telescope but, I suppose, a time-exposure would capture objects otherwise invisible-to-unaided human eyes.

Actually, a "telescope" is an afocal optical device that has a magnification factor- it does not have a focal plane, and the angle of an incoming ray is changed at the output. A telescope requires a minimum of two optical components- an objective and an ocular. So images are never made through telescopes. Making an image requires optics that can bring light to a focus. In other words, just the objective. So the "telescopes" that we use for imaging- whether something small in our backyard, a giant Keck, or the Hubble- none of these are actually telescopes at all. What else is like this? A camera lens. Optically, a camera lens is just an objective, which brings light to a focus at the sensor. Exactly like an astronomical telescope used for imaging.

This image was as much taken with a telescope (or not) as any other astronomical image we see. This telescope has a rather short focal length compared with most, so we have a wide field of view. But there are professional survey telescopes that are similarly short.

And yes, collecting more information is just a question of collecting more photons. With an instrument, we can do that two ways- more aperture, or more exposure time. Unfortunately, neither of those options are available to the human eye, which has a fixed maximum aperture and a maximum exposure time on the order of 100 milliseconds.

Starship Asterisk*

APOD: Andromeda Rising over the Alps (2015 Aug 17)

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