Starship Asterisk*

by **aristarchusinexile** » Tue May 26, 2009 2:02 pm

Zero Hour and Pipes? No Bong? No Cheech and Chong? "When I was a young man Momma told me how to live: But I didn't listen 'cause my head was like a sieve" Darned vixens luring me away from fishing.

by **neufer** » Mon May 25, 2009 10:00 pm

neufer wrote:
astrolabe wrote:Hello neufer,

A while back an image was posted that showed the red and blue shifting in the CMB indicating to me our movement in the Universe relative to it. The question that follows is this: Are we advancing toward Andromeda in relation to the CMB or is it the other way around?
Our whole local group of galaxies is moving at ~627 km/s in the direction
of galactic longitude l = 276°, b = 30° (vis-a-vis the CMB).

Now relative to our local group of galaxies the Andromeda Galaxy
is moving at ~150 km/s in more or less the same direction:
galactic longitude l = 301°, b = 22°.

So the Andromeda Galaxy is the faster [627+150 km/s] dog
chasing us (the slower [627-150 km/s] Milky Way cat)
as we all move in more or less the same direction vis-a-vis the CMB.

Of course the Local Group could just be going with the flow:
---------------------------------------

http://en.wikipedia.org/wiki/Dark_flow wrote:
<<Dark flow is a name given to a net motion of galaxy clusters with respect to the cosmic microwave background radiation which was found in a 2008 study. According to standard cosmological models, the motion of galaxy clusters with respect to the cosmic microwave background should be randomly distributed in all directions. However, analyzing the three-year WMAP data using the kinematic Sunyaev-Zel'dovich effect, the authors of the study found evidence of a common motion of at least 600 km/s toward a 20-degree patch of sky between the constellations of Centaurus and Vela [galactic longitude l = 285°, b = 9°].

The authors suggest that the motion may be a remnant of the influence of no-longer-visible regions of the universe prior to inflation. Telescopes cannot see events earlier than about 380,000 years after the Big Bang, when the universe became transparent; this corresponds to the particle horizon at a distance of about 46 billion light years. Since the matter causing the net motion in this proposal is outside this range, it would in a certain sense be outside our visible universe; however, it would still be in our past light cone.

The results appear in the October 20, 2008, issue of Astrophysical Journal Letters, which is available online. The authors state that they plan to extend their analysis to additional clusters and the recently released WMAP five-year data.

Astrophysicist Ned Wright posted an online response to the study arguing that its methods are flawed. The authors of the "dark flow" study released a statement in return, refuting three of Wright's five arguments and identifying the remaining two as a typo and a technicality, respectively, that, they say, do not affect the measurements and their interpretation.>>

---------------------------------------

. Finnegans Wake p 404

I heard at zero hour as 'twere the peal of vixen's laughter among
midnight's chimes from out the belfry of the cute old speckled church
tolling so faint a goodmantrue as nighthood's unseen violet
rendered all animated greatbritish and Irish objects nonviewable
to human watchers save 'twere perchance anon some
glistery gleam darkling adown surface of affluvial flowandflow
as again might seem garments of laundry reposing
a leasward close at hand in full expectation.

---------------------------------------

by **aristarchusinexile** » Mon May 25, 2009 4:02 pm

mark swain wrote:When the main man found that no matter how fast you can go.. light is always at a constant speed. Was he thinking outside the box? Or was he looking for something that everybody already knew? Or just an answer to what everybody wanted to know.. Are there no more questions that need answers? I,m as interested as Noelc to know the answers..To find something nobody has ever Found , Don,t you have to think out side the box?
Mark

I can't imagine why the speed of light should at all be regulated by our speed .. recognizing of course that our speed is not regulating the speed of light .. but I can't imagine why it should be a surprise that our speed does not affect the speed of light .. and I repeat finding no reason that the speed of light must remain constant regardless of observer or condition of observer. Laws are simply (and unfortunately sometimes) not inviolable.

by **The Code** » Mon May 25, 2009 3:31 pm

When the main man found that no matter how fast you can go.. light is always at a constant speed. Was he thinking outside the box? Or was he looking for something that everybody already knew? Or just an answer to what everybody wanted to know.. Are there no more questions that need answers? I,m as interested as Noelc to know the answers..To find something nobody has ever Found , Don,t you have to think out side the box?

Mark

by **aristarchusinexile** » Mon May 25, 2009 2:58 pm

bystander wrote:" ... Perhaps it's time itself that is variable.

Excellent step up towards a more freestyle contemplation. But I honestly cannot imagine why anyone would negate the probability of variable speed of light.

by **Chris Peterson** » Mon May 25, 2009 3:57 am

bystander wrote:Yes, I find it hard to give much credence to these theories because they require a variable speed of light and other inconstant physical constants (variable over time). Perhaps it's time itself that is variable. It's far easier for me to believe that there is something out there that we haven't been able to directly observe that is holding galaxies, clusters, and super-clusters together (dark matter) and something else causing the universe to fly apart (dark energy).

I also don't give them much credence, because they don't seem to solve any problems. They aren't needed, and in my view they produce a more complex, less likely explanation for what we see. But at least, those are actually scientific theories, subject to test. Not very strong ones, but a good deal better than much of the speculation that gets casually tossed around sometimes.

by **bystander** » Mon May 25, 2009 3:19 am

Chris Peterson wrote:In fact, there are a couple of a widely regarded theories that deal with questions along the lines of yours. They do work quite well, and don't depend on anything that is "invisible".

Yes, I find it hard to give much credence to these theories because they require a variable speed of light and other inconstant physical constants (variable over time). Perhaps it's time itself that is variable. It's far easier for me to believe that there is something out there that we haven't been able to directly observe that is holding galaxies, clusters, and super-clusters together (dark matter) and something else causing the universe to fly apart (dark energy).

by **Chris Peterson** » Sun May 24, 2009 11:30 pm

NoelC wrote:Let me toss this snide comment right back at you - your "working theory" doesn't model reality particularly well. Look at all the invisible crap that has had to be invented (dark this and that) to make it work. And from what I can see not everyone agrees on ONE working theory either, so there is no "we" as you'd like to imply. Try not to be so uppity. There is room for more than just your opinion here.

Sorry, Noel. Sometimes tone doesn't come across as intended in forums like this. I wasn't being snide at all, my questions to you were serious ones.

There are tools that we can use to separate idle speculation from scientifically answerable questions. Your questions need quite a lot of additional development before they can even be considered seriously. Hence, my questions.

In fact, there are a couple of a widely regarded theories that deal with questions along the lines of yours. They do work quite well, and don't depend on anything that is "invisible". Any new ideas really do have to be considered in the context of existing, well supported theory. That is, in what way do the new ideas solve problems in existing theory? In what way do the new ideas improve upon or simplify the existing theory? How could we test the new ideas?

by **NoelC** » Sun May 24, 2009 11:03 pm

Aw c'mon. There's no rule here that says everything written has to be hard science. Philosophy helps people reach for science; I'm just throwing things out there to help the less technical among us expand their thought processes. To make them wonder. To get them thinking.

Frankly I don't care to think on this particular subject hard enough to even try to understand current theory. It's not what lights my fire. As I noted quite clearly, I certainly don't have my head around it.

frankly, not very good philosophy

Let me toss this snide comment right back at you - your "working theory" doesn't model reality particularly well. Look at all the invisible crap that has had to be invented (dark this and that) to make it work. And from what I can see not everyone agrees on ONE working theory either, so there is no "we" as you'd like to imply. Try not to be so uppity. There is room for more than just your opinion here.

-Noel

by **Chris Peterson** » Sun May 24, 2009 9:38 pm

NoelC wrote:What if the universe is not expanding at all?

What if the passage of time isn't constant?

Maybe it's still the size of a pea.

From an observer inside if the passage of time changed it might seem that things are getting farther apart as photons would take longer to get from one place to another.

Very few folks (certainly not I) can get their heads around this kind of relativity.

Well, you can play "what if" games all you like, but what's the real point? We have a working theory, it describes what we see, and has been useful in predicting observations and guiding experiment design. That's all that science asks.

For your questions to make sense, you'd need to find a way to express them scientifically. For instance, what does it mean that "time isn't constant"? Constant compared to what? What does it mean to be "the size of a pea"? In what fundamental units? If the Universe is the size of a pea, how big is an actual pea?

How can you express the questions so they could be tested? Otherwise, it's just philosophy (and frankly, not very good philosophy).

by **NoelC** » Sun May 24, 2009 9:28 pm

What if the universe is not expanding at all?

What if the passage of time isn't constant?

Maybe it's still the size of a pea.

From an observer inside if the passage of time changed it might seem that things are getting farther apart as photons would take longer to get from one place to another.

Very few folks (certainly not I) can get their heads around this kind of relativity.

-Noel

by **astrolabe** » Sun May 24, 2009 7:04 pm

Hello Chris,

Thank you for the correction.

Just goes to show that good intent doesn't necessarily get followed by fact.
93 billion ly diameter it is.

by **Chris Peterson** » Sun May 24, 2009 6:21 pm

astrolabe wrote:Approximately 46 billion ly. across now by some estimates and which has taken about 13.7 billion lyrs. for it to get to that diameter.

Radius. The diameter is 93 billion ly. And to be clear, that's the observable universe. The entire thing is almost certainly larger- probably much larger.

by **astrolabe** » Sun May 24, 2009 5:24 pm

Hello DavidLeodis,

As has been said in other threads (not by me 'cause, like you, I'm a relative novice) that the Universe creates space as it goes. Approximately 46 billion ly. across now by some estimates and which has taken about 13.7 billion lyrs. for it to get to that diameter. Mind boggling to be sure! Some have said that beyond the visible parameter the Universe could be much larger -even infinite- but without the instruments there is no way of knowing and most if not all arguments concerning the nature of the great beyond are mental exercises only and rather futile. No one can tell yet if in fact there are influences at all beyond what humans can currently see. IMHO we have quite enough to keep us busy as it is! But this is as you say a good thread- very interesting indeed.

Ya think?

by **DavidLeodis** » Sun May 24, 2009 4:58 pm

This is a fascinating discussion, which I've read with interest even though most of it is beyond me!

As to an expanding Universe I can't help but wonder, if it is expanding just what is it expanding into

.

I stll think the image is awesome.

by **neufer** » Sun May 24, 2009 5:19 am

astrolabe wrote:Hello neufer,

A while back an image was posted that showed the red and blue shifting in the CMB indicating to me our movement in the Universe relative to it. The question that follows is this: Are we advancing toward Andromeda in relation to the CMB or is it the other way around?

Our whole local group of galaxies is moving at ~627 km/s in the direction
of galactic longitude l = 276°, b = 30° (vis-a-vis the CMB).

Now relative to our local group of galaxies the Andromeda Galaxy
is moving at ~150 km/s in more or less the same direction:
galactic longitude l = 301°, b = 22°.

So the Andromeda Galaxy is the faster [627+150 km/s] dog
chasing us (the slower [627-150 km/s] Milky Way cat)
as we all move in more or less the same direction vis-a-vis the CMB.

(It's late at night so someone might want to check my back of the envelope calculations.)

by **neufer** » Sun May 24, 2009 5:07 am

Chris Peterson wrote:I think your assessment is correct, or nearly so. The fields found between the bound members of galaxy clusters aren't strong enough to completely counter expansion. Eventually most galaxy clusters will come apart (except where some of their components first merge).

Thanks, Chris. There is a lot of stuff I don't understand very well...and even the stuff I sort of understand I don't necessarily explain it well.

by **Chris Peterson** » Sun May 24, 2009 4:46 am

neufer wrote:Perhaps...but let us take the case of the Andromeda Galaxy whose Doppler shift
(for some bizarre reason) IS only capable of being measured to a few kilometers per second:

The Andromeda Galaxy is observed to be advancing at 301 ± 1 km/s.

The Andromeda Galaxy is located about 0.778 Mpc away.

Hubble expansion constant ~ 74.2 (km/s)/Mpc.
Now I would argue that the Andromeda Galaxy is retreating by about 58 km/s (= 74.2 x 0.778) due to universal expansion but it is actually observed to be advancing at 301 ± 1 km/s thanks to a combination of a strong initial velocity and (to a much lesser extent) by its attraction to the Milky Way.

I'm assuming that you would argue that there IS no expansion within the Local (Galactic) Group because the gravitational field of the Local (Galactic) Group is too strong to allow the local space to expand. Is that your argument? (At what point is universal expansion finally allowed?).

No, I think your assessment is correct, or nearly so. The fields found between the bound members of galaxy clusters aren't strong enough to completely counter expansion. Eventually most galaxy clusters will come apart (except where some of their components first merge).

by **astrolabe** » Sun May 24, 2009 2:34 am

Hello neufer,

A while back an image was posted that showed the red and blue shifting in the CMB indicating to me our movement in the Universe relative to it. The question that follows is this: Are we advancing toward Andromeda in relation to the CMB or is it the other way around? Now, I know it could be mutual unless one was chasing the other because a third party (or more) may have some dynamic influence. I am also thinking that the expansion of space in between (if it exists) is still happening and that it probably expands everywhere, even within or through galaxies, but inter/intra galactic processes overpower it's properties. What can I say I'm like the village idiot of sorts and constantly strive to oversimplify things so I can grasp ideas until called wrong.

by **neufer** » Sun May 24, 2009 12:53 am

Chris Peterson wrote:
neufer wrote:Well, if it really is universal expansion (i.e., the expansion of space time itself) then it ought to take place within galaxies as well, although not nearly enough (a few kilometers per second) that one would notice it compared to other galactic motions.
What you calculated from the Hubble constant was the expansion of the Universe. But we don't see that expansion within the galaxy (and we are easily capable of measuring a few kilometers per second using Doppler shift) because the gravitational field of the galaxy is much too strong to allow the local space to expand.

Perhaps...but let us take the case of the Andromeda Galaxy whose Doppler shift
(for some bizarre reason) IS only capable of being measured to a few kilometers per second:

The Andromeda Galaxy is observed to be advancing at 301 ± 1 km/s.

The Andromeda Galaxy is located about 0.778 Mpc away.

Hubble expansion constant ~ 74.2 (km/s)/Mpc.

Now I would argue that the Andromeda Galaxy is retreating by about 58 km/s (= 74.2 x 0.778) due to universal expansion but it is actually observed to be advancing at 301 ± 1 km/s thanks to a combination of a strong initial velocity and (to a much lesser extent) by its attraction to the Milky Way.

I'm assuming that you would argue that there IS no expansion within the Local (Galactic) Group because the gravitational field of the Local (Galactic) Group is too strong to allow the local space to expand. Is that your argument? (At what point is universal expansion finally allowed?).

Chris Peterson wrote:
neufer wrote:However, if what we are talking about is simply the recoil of galaxies from an initial explosion (with slowing due to matter and expansion due to dark energy) then I agree that that is a somewhat different matter. But if that is the case, I don't understand why it has taken so long for photons from the cosmic microwave background to reach us. (But, then, there are a lot of things that I don't understand.)
The photons from the edge of the observable Universe have been reaching us for 13.7 billion years (or so). In the beginning, they were much more energetic. Over the billions of years, as space expanded, they have had their wavelength stretched more and more by expanding space. What we're seeing now was emitted 13.7 billion years ago, but is only now reaching us because the space between the emitting material and us has expanded so far (47+ billion light years). In another 13.7 billion years we'll still see the photon background, but it will be even colder.

So... space expands (and photon wavelengths are stretched) only between Local (Galactic) Groups and never within a Local (Galactic) Group?

by **astrolabe** » Sun May 24, 2009 12:02 am

Hello Chris,

So using the Hubble Constant how big will the visible universe be in another 13.7 billion yrs? This is of course if someone was still around to see it. If so, the instrumentation would have to good enough to see back to 600 million years after the Bang at least in order to actually see anything at distance "x". I wonder if if any one or any instrument would survive if the technology then could, when viewing through some apparatus, allow a view of the BB itself?

Could be Cosmologies version of the Tower of Babel in which the civilization at that time tried to build a tower up to heaven and therefore see God. The biblical story could have been an oral account finally written down of a previous civilization before this one that was highly advanced and destroyed itself somehow. I've always felt so even though it's far, far from probable.

by **Chris Peterson** » Sat May 23, 2009 10:48 pm

neufer wrote:Well, if it really is universal expansion (i.e., the expansion of space time itself) then it ought to take place within galaxies as well, although not nearly enough (a few kilometers per second) that one would notice it compared to other galactic motions.

What you calculated from the Hubble constant was the expansion of the Universe. But we don't see that expansion within the galaxy (and we are easily capable of measuring a few kilometers per second using Doppler shift) because the gravitational field of the galaxy is much too strong to allow the local space to expand.

However, if what we are talking about is simply the recoil of galaxies from an initial explosion (with slowing due to matter and expansion due to dark energy) then I agree that that is a somewhat different matter. But if that is the case, I don't understand why it has taken so long for photons from the cosmic microwave background to reach us. (But, then, there are a lot of things that I don't understand.)

The photons from the edge of the observable Universe have been reaching us for 13.7 billion years (or so). In the beginning, they were much more energetic. Over the billions of years, as space expanded, they have had their wavelength stretched more and more by expanding space. What we're seeing now was emitted 13.7 billion years ago, but is only now reaching us because the space between the emitting material and us has expanded so far (47+ billion light years). In another 13.7 billion years we'll still see the photon background, but it will be even colder.

by **neufer** » Sat May 23, 2009 9:50 pm

Chris Peterson wrote:
neufer wrote:The Galactic Center is located about .0076 Mpc away.

Hubble expansion constant = 74.2 ± 3.6 (km/s)/Mpc.

Galactic Center is retreating by 1261 miles per hour due to galactic expansion.
I'm a little confused. Galactic expansion? What's that? I'm guessing (since the calculation works) that you mean Universal expansion. However, the Milky Way is gravitationally bound, and is not itself getting any larger due to the expansion of the Universe. We don't see the galactic center retreating.

Well, if it really is universal expansion (i.e., the expansion of space time itself) then it ought to take place within galaxies as well, although not nearly enough (a few kilometers per second) that one would notice it compared to other galactic motions. However, if what we are talking about is simply the recoil of galaxies from an initial explosion (with slowing due to matter and expansion due to dark energy) then I agree that that is a somewhat different matter. But if that is the case, I don't understand why it has taken so long for photons from the cosmic microwave background to reach us. (But, then, there are a lot of things that I don't understand.)

by **Chris Peterson** » Sat May 23, 2009 9:17 pm

neufer wrote:The Galactic Center is located about .0076 Mpc away.

Hubble expansion constant = 74.2 ± 3.6 (km/s)/Mpc.

Galactic Center is retreating by 1261 miles per hour due to galactic expansion.

I'm a little confused. Galactic expansion? What's that? I'm guessing (since the calculation works) that you mean Universal expansion. However, the Milky Way is gravitationally bound, and is not itself getting any larger due to the expansion of the Universe. We don't see the galactic center retreating.

However, we do see changes in many nebulas over a fairly short period- years or less- because they are typically very dynamic (and nearby) objects. Everthing to do with moving material, and nothing at all with the dynamics of the Universe.

by **neufer** » Sat May 23, 2009 12:09 pm

DavidLeodis wrote:Yes NoelC, it is a wonderful view. It must be amazing to be able to see such a clear sky view.

Realising that the image seemed very famiIiar I've just done a search of the APOD archive and found the APOD of June 23 2006 http://antwrp.gsfc.nasa.gov/apod/ap060623.html. That the image in the two APODs is so very similar should not perhaps be a surprise, but I still think it's awesome that there is no really obvious change despite that the Universe is said to be expanding rapidly. 8)

The Galactic Center is located about .0076 Mpc away.

Hubble expansion constant = 74.2 ± 3.6 (km/s)/Mpc.

Galactic Center is retreating by 1261 miles per hour due to galactic expansion.

Retired Concorde aircraft cruising speed for optimum fuel consumption: 1400 miles per hour
(supersonic drag minimum, although turbojet engines are more efficient at high speed)

Starship Asterisk*

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