Starship Asterisk*

by **crosscountry** » Thu Jan 06, 2005 1:31 pm

Why do galaxies with small black holes still exibit characteristics due to dark matter?

I guess the question is:

Large Galaxies with large black holes exhibit characteristics of dark matter.

Small Galaxies with small or no black holes also exhibit those characteristics.

So how could a no-black-hole-galaxy produce dark matter?

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I kind of like the string theory idea. (not that I'm too fond of string theory). It suggests that there is a lot of matter on other membranes "branes" (or dimensions) that we cannot see. it's still there though and through gravitons helps hold our universe together.

I'm still kind of iffy on gravitons though. We've never seen one.

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

anyone heard about the guy that studied the motions of the Voyagers. He said their positions were off after many years. There was no venting or other failure that could attest for the large discrepency. There was an article I read not too long ago that suggested dark matter caused it.

by **path** » Thu Jan 06, 2005 2:32 am

If what you are saying is that black holes make dark matter that raises questions. but I feel that it's not true. black holes come in different sizes. what size does it take to "churn" dark matter? Why do galaxies with small black holes still exibit characteristics due to dark matter?[/quote]

Yes, I am suggesting that black holes churn matter (and thanks for that term "churn") You ask what size black hole is needed. By definititon, any size black hole can churn matter. What happens to the matter that goes into the black hole? There are several possibilities I think. The matter is changed (churned, but not created or destroyed) into some other entity that we can't describe because it isn't detected by our current methods of measurement. It may remain undetected for some period of time or space until it recombines with other matter in our visible universe, or not. But the matter consumed by a black hole is surely moving, and not in a straight line.
I don't understand the last question.

by **crosscountry** » Wed Jan 05, 2005 3:25 am

path wrote:
-=Arramon=- wrote:um... holy unlimited bliss batman..!

So then... who out there still thinks we are the only ones here?

=)

So if it would take 1 million uninterrupted years to observe the full range of what encompasses us, what if there were hundreds, or thousands of telescopes doing this at one time? All capable of the Ultra Deep Field views?

'Course it would help... but how much time could that save if more instruments were created to do this, or the Ultra Deep Field was enhanced to provide even more coverage, with the same depth...?

Too many galaxies...!

Hmm... what if that 'straw' could be made to look even further?
What would it take to peer through the CMB?

Also... is there such a technology that could send out a light source (laser even) that could send information back to earth? I'm not sure how far our science has come, but what if we could bounce a beam off of some object in space and have it return to our general area, information stored within it of what it's seen, so that we could analyze... CAN information be stored within a light source?

My mind won't stop... =)

I luv space!!!
Arramon
I think that the question you raised was part of a famous bet. Stephen Hawking conceded he was wrong that no light/matter comes out of a black hole with the recent statement that "information" can never be destroyed. He conceded the bet saying that whatever information passes through a black hole remains intact. He paid the $100, but I suspect we have not heard the end of this. Hence, your question, "Can information be stored within a light source?" might receive a positive response from Mr. Hawking.
Is it space you love, or physics?
I happen to think that black holes are great recyclers, transforming matter we know into things we don't have the physics to explain yet (dark matter anyone?). I also believe black holes move.

sure black holes can move. they experience forces from all other objects just like you and I.

from what I understand (very little) dark matter has nothing to do with a black hole. We can measure the gravitational effect of all the "visible matter" and even black holes (by watching orbiting objects). Those together don't make up enough matter to bind a galaxy.

If what you are saying is that black holes make dark matter that raises questions. but I feel that it's not true. black holes come in different sizes. what size does it take to "churn" dark matter? Why do galaxies with small black holes still exibit characteristics due to dark matter?

by **Guest** » Mon Jan 03, 2005 8:44 pm

The wikipedia does a nice job of differentiating between the visible universe and the known universe. English link.

~Neal

by **path** » Mon Jan 03, 2005 1:09 am

-=Arramon=- wrote:um... holy unlimited bliss batman..!

So then... who out there still thinks we are the only ones here?

=)

So if it would take 1 million uninterrupted years to observe the full range of what encompasses us, what if there were hundreds, or thousands of telescopes doing this at one time? All capable of the Ultra Deep Field views?

'Course it would help... but how much time could that save if more instruments were created to do this, or the Ultra Deep Field was enhanced to provide even more coverage, with the same depth...?

Too many galaxies...!

Hmm... what if that 'straw' could be made to look even further?
What would it take to peer through the CMB?

Also... is there such a technology that could send out a light source (laser even) that could send information back to earth? I'm not sure how far our science has come, but what if we could bounce a beam off of some object in space and have it return to our general area, information stored within it of what it's seen, so that we could analyze... CAN information be stored within a light source?

My mind won't stop... =)

I luv space!!!

Arramon
I think that the question you raised was part of a famous bet. Stephen Hawking conceded he was wrong that no light/matter comes out of a black hole with the recent statement that "information" can never be destroyed. He conceded the bet saying that whatever information passes through a black hole remains intact. He paid the $100, but I suspect we have not heard the end of this. Hence, your question, "Can information be stored within a light source?" might receive a positive response from Mr. Hawking.
Is it space you love, or physics?
I happen to think that black holes are great recyclers, transforming matter we know into things we don't have the physics to explain yet (dark matter anyone?). I also believe black holes move.

by **Guest** » Wed Dec 29, 2004 4:21 pm

RJ Emery wrote:Arramon asks:

what percentage of our visible universe is this Ultra Deep Field image of?
I take his query to mean "What area of the celestial sphere does the UDF cover?"

I did a Google search using the keywords "arcsec hubble ultra deep field." From the page hits, it appears the area covered by the Ultra Deep Field (UDF) is 0.2 sq arcsec. By contrast, the area for the Hubble Deep Field (HDF) was 90 sq arcsec. There are 86,400 (24x60x60) arcsec in any celestial great circle. Without doing the calculation, it is an incredibly small area percentage wise.

Thanks for the misinformation. You seem to have your units confused.
There are 360x60x60 arcseconds or 24x60x60 "seconds" on the sky.

The HUDF is 10500x10500 pix at 0.03" scale or 99225 sq arcsec.
This corresponds to aprrox 0.024% of "our" visible universe at the limiting
magnitude of the HUDF (which depends on wavelength).

Unfortunately most of the well known "expanding" Universe is not observable at
visible wavelengths (as per HUDF images) due to redshift. To truely understand
what fraction of the universe we are seeing we would have to adopt a cosmological model and correct for completeness and wavelength biases. Needless to say the
volume we can see in these images is much less than 0.001%

We are not at the center of the universe we are only at the center of what we can
see at the current time, which one might call our visible universe.

The big bang does not emanate from a primoridal atom but a singularity.
A singularity is not an atom. An atom is composed of protonos, neutrons and
electrons which are composed of quarks in various flavors. These may or may
not themselves be composed of strings depending on if you believe M-theory
or not. If you really want to understand cosmology you could read some of the
articles discussed by professionals here: http://cosmocoffee.info/index.php

by **RJ Emery** » Wed Dec 29, 2004 4:26 am

Arramon asks:

what percentage of our visible universe is this Ultra Deep Field image of?

I take his query to mean "What area of the celestial sphere does the UDF cover?"

I did a Google search using the keywords "arcsec hubble ultra deep field." From the page hits, it appears the area covered by the Ultra Deep Field (UDF) is 0.2 sq arcsec. By contrast, the area for the Hubble Deep Field (HDF) was 90 sq arcsec. There are 86,400 (24x60x60) arcsec in any celestial great circle. Without doing the calculation, it is an incredibly small area percentage wise.

by **RJ Emery** » Wed Dec 29, 2004 4:16 am

Dan writes:

However, every second, every day, the "visible" universe gets larger because more light arrives at Earth.

I'm not certain the above is a correct statement. We already see the light from the Big Bang. If the visible universe is getting bigger, it is because the universe continues to expand. I do not believe that any more light is reaching us than before.

Moreover, the entire universe is much larger than what we can see and may very well be infinite. Turning the clock back, we think of the Big Bang as emanating from a primoridal atom, but that atom may just have been one of many that underwent expansion, presumably in the same manner as the atom that gave birth to our universe. This enters the realm of quantum cosmology, a topical area I am still struglling to grasp.

by **Can't use my Bad Buoy** » Sun Dec 26, 2004 3:50 pm

Yes, you are quite right in making the distinction between the 'visible' and 'known' universe.

We don't yet know if we're outward bound from an ongoing event, or just part of the expanding shockwave.

by **Dan Cordell** » Thu Oct 14, 2004 1:34 pm

BMAONE wrote:IF YOU LOOK AT THE ULTRA DEEP FIELD PICTURES AND CONSIDER THAT IT WAS TAKEN IN ONE DIRECTION ABOUT AS FAR AWAY (BACK) AS WE CAN SEE, DOES THE KNOWN UNIVERSE EXTEND THE SAME DISTANCE AWAY ON ALL SIDES? IN OTHER WORDS, ARE WE IN THE CENTER OF THE KNOWN UNIVERSE? OR CAN WE SEE FARTHEST BACK IN TIME IN ONLY ONE DIRECTION?

We are the center of the visible universe.

However, every second, every day, the "visible" universe gets larger because more light arrives at Earth.

As for the known universe, I suppose that'd be the same as the visible universe. However, it would be the SAME situation for ANY location--to an observer on a planet in the Andromeda galaxy, their visible universe would be centered on them.

by **BMAONE** » Fri Oct 08, 2004 5:12 pm

IF YOU LOOK AT THE ULTRA DEEP FIELD PICTURES AND CONSIDER THAT IT WAS TAKEN IN ONE DIRECTION ABOUT AS FAR AWAY (BACK) AS WE CAN SEE, DOES THE KNOWN UNIVERSE EXTEND THE SAME DISTANCE AWAY ON ALL SIDES? IN OTHER WORDS, ARE WE IN THE CENTER OF THE KNOWN UNIVERSE? OR CAN WE SEE FARTHEST BACK IN TIME IN ONLY ONE DIRECTION?

by **Sowndbyte** » Sat Oct 02, 2004 3:16 am

interesting theory I have to share here.
The lifetime of light is 16 Billion years. as this is how far we can see.
Some profess that we are looking at the beginning of All there is. The Big Bang, or as near to it as technologically possible at this time. perhaps it is opposite, we are seeing the end of lights life. having looked in every direction and seeing basically the same thing for the same distance , we should begin to consider that we are not in the center of it all (which by light we seem to be) but rather that their truly is no energy source which lasts eternally,and Light like all other energies is finite.

by **-=Arramon=-** » Thu Sep 30, 2004 4:07 pm

um... holy unlimited bliss batman..!

So then... who out there still thinks we are the only ones here?

=)

So if it would take 1 million uninterrupted years to observe the full range of what encompasses us, what if there were hundreds, or thousands of telescopes doing this at one time? All capable of the Ultra Deep Field views?

'Course it would help... but how much time could that save if more instruments were created to do this, or the Ultra Deep Field was enhanced to provide even more coverage, with the same depth...?

Too many galaxies...!

Hmm... what if that 'straw' could be made to look even further?
What would it take to peer through the CMB?

Also... is there such a technology that could send out a light source (laser even) that could send information back to earth? I'm not sure how far our science has come, but what if we could bounce a beam off of some object in space and have it return to our general area, information stored within it of what it's seen, so that we could analyze... CAN information be stored within a light source?

My mind won't stop... =)

I luv space!!!

by **The Meal** » Thu Sep 30, 2004 1:09 pm

source

If astronomers made the Hubble Ultra Deep Field observation over the entire sky, how long would it take?

The whole sky contains 12.7 million times more area than the Ultra Deep Field. To observe the entire sky would take almost 1 million years of uninterrupted observing.

How wide is the Ultra Deep Field's slice of the heavens?

The Hubble Ultra Deep Field is called a "pencil beam" survey because the observations encompass a narrow, yet "deep" piece of sky. Astronomers compare the Ultra Deep Field view to looking through an eight-foot-long soda straw.

The Ultra Deep Field's patch of sky is so tiny it would fit inside the largest impact basin that makes up the face on the Moon. Astronomers would need about 50 Ultra Deep Fields to cover the entire Moon.

~The Meal

by **Dan Cordell** » Thu Sep 30, 2004 12:21 am

Good question, and you're about right--it's a very very small percentage of our visible universe.

I'm not sure of the exact number though.

by **-=Arramon=-** » Wed Sep 29, 2004 5:02 pm

I love this image they have hosted right now for Sept 29th. But what I want to know is... what percentage of our visible universe is this Ultra Deep Field image of?

Like .03% or something crazy like that?

Maybe I missed a link that says this. Just thought I'd ask and say how much I enjoy seeing images like these, because of the TRUTH it shows of what is really out there... on an Eternal scale.

Starship Asterisk*

Distant Galaxies in the Hubble Ultra Deep Field... what %?

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Distant Galaxies in the Hubble Ultra Deep Field... what %?