More normal dark matter found between the Andromeda & Triangulumgalaxies

A couple of years ago, it was found that there were some streamers of
gas that were flowing between Andromeda and Triangulum, which scientists
thought were the result of a possible near collision between them.

Neighbor galaxies may have brushed closely, astronomers find
http://www.sciencedaily.com/releases...0611193632.htm

But now, after some further analysis, they are finding that there may be
something more significant here. They think the gas between the galaxies
are as massive as dwarf galaxies, but just more diffuse, so there are no
stars that formed in them. So the nearly invisible gas is likely to be
independent from either galaxy. What's more, they think that this gas
came from an even bigger clutch of gas that has so far remained invisible.

Astronomers discover surprising clutch of hydrogen clouds lurking among
our galactic neighbors
http://www.sciencedaily.com/releases...0508131700.htm

If this is true, then it's making it more and more unnecessary to look
for exotic WIMPs and other such things to explain dark matter, as dark
matter may simply be this invisible gas between galaxies.

Yousuf Khan

Yousuf Khan wrote:
A couple of years ago, it was found that there were some streamers of
gas that were flowing between Andromeda and Triangulum, which
scientists thought were the result of a possible near collision
between them.
Neighbor galaxies may have brushed closely, astronomers find
http://www.sciencedaily.com/releases...0611193632.htm

But now, after some further analysis, they are finding that there may
be something more significant here. They think the gas between the
galaxies are as massive as dwarf galaxies, but just more diffuse, so
there are no stars that formed in them. So the nearly invisible gas
is likely to be independent from either galaxy. What's more, they
think that this gas came from an even bigger clutch of gas that has
so far remained invisible.
Astronomers discover surprising clutch of hydrogen clouds lurking
among our galactic neighbors
http://www.sciencedaily.com/releases...0508131700.htm

If this is true, then it's making it more and more unnecessary to look
for exotic WIMPs and other such things to explain dark matter, as dark
matter may simply be this invisible gas between galaxies.

This hypothesis does nothing to address the problem of dark matter being
present in galaxies. The rotation curves of spiral galaxies, for example,
was one of the first clues that dark matter exists and does not interact
with other matter except through gravitation. Another clue is in the
gravitational lensing of distant galaxies caused by massive elliptical
galaxies in clusters. There is far more lensing effect than can be
accounted for in the stellar populations, and ellipticals have very little
interstellar hydrogen.

--
Mike Dworetsky

(Remove pants sp*mbl*ck to reply)

On 09/05/2013 12:58 PM, Mike Dworetsky wrote:
Yousuf Khan wrote:
If this is true, then it's making it more and more unnecessary to look
for exotic WIMPs and other such things to explain dark matter, as dark
matter may simply be this invisible gas between galaxies.

This hypothesis does nothing to address the problem of dark matter being
present in galaxies. The rotation curves of spiral galaxies, for
example, was one of the first clues that dark matter exists and does not
interact with other matter except through gravitation. Another clue is
in the gravitational lensing of distant galaxies caused by massive
elliptical galaxies in clusters. There is far more lensing effect than
can be accounted for in the stellar populations, and ellipticals have
very little interstellar hydrogen.

Actually, it's been shown time and time again, that the rotation curves
of nearly all galaxies is better explained by modified gravity theories,
rather than dark matter. Even Dark Matter supporters admit that much,
but they have so far stated that despite this the gravitational lensing
of galaxy clusters is better explained by dark matter.

However, if there is so many hard to detect unlit dwarf galaxies just
sitting between lit galaxies, they could also account for gravitational
lensing inside clusters. If they are so hard to detect just within our
own local cluster, they would be almost impossible to detect even in
neighboring clusters, let alone distant ones. And to an extent, they
would still actually qualify as dark matter, only back in the old
competing MACHO's form of dark matter rather than the WIMP's form.

Yousuf Khan

Dear Mike Dworetsky:

On Wednesday, May 8, 2013 11:58:05 PM UTC-7, Mike Dworetsky wrote:
Yousuf Khan wrote:

If this is true, then it's making it more and
more unnecessary to look for exotic WIMPs and
other such things to explain dark matter, as
dark matter may simply be this invisible gas
between galaxies.

This hypothesis does nothing to address the
problem of dark matter being present in galaxies.
The rotation curves of spiral galaxies, for
example, was one of the first clues that dark
matter exists and does not interact with other
matter except through gravitation.

This has been shown to be an error in the intervening decades. They calibrate the spiral galaxy at its center, assuming it has normal luminosity vs. normal mass distribution, and the Dark Matter component is small. We know this area has a large dark matter collection (the black hole), the area is swept clear, and is abnormally hot (higher luminosity on average than stars near us). The areas further from the center are smaller and cooler, and there is plenty of interstitial dust, so any sort of linear relationship is fatally flawed.

Another clue is in the gravitational lensing of
distant galaxies caused by massive elliptical
galaxies in clusters. There is far more lensing
effect than can be accounted for in the stellar
populations, and ellipticals have very little
interstellar hydrogen.

More bad assumptions. We cannot see the actual stars in the elliptical galaxies, so we SWAG at their populations, and we make the same errors in distributions. Add to this that we expect the "interstellar hydrogen" to be in ground state, but the lion's share of what we are finding is ionized hydrogen and ionized oxygen. Which will be "dark" to optical wavelengths.

It can be simply normal matter, neutrinos, and black holes. We need to look for other options, but it clearly wrong to assume Dark Matter is a fact.

David A. Smith

On 5/8/13 7:11 PM, Yousuf Khan wrote:
A couple of years ago, it was found that there were some streamers of
gas that were flowing between Andromeda and Triangulum, which scientists
thought were the result of a possible near collision between them.

Neighbor galaxies may have brushed closely, astronomers find
http://www.sciencedaily.com/releases...0611193632.htm

But now, after some further analysis, they are finding that there may be
something more significant here. They think the gas between the galaxies
are as massive as dwarf galaxies, but just more diffuse, so there are no
stars that formed in them. So the nearly invisible gas is likely to be
independent from either galaxy. What's more, they think that this gas
came from an even bigger clutch of gas that has so far remained invisible.

Astronomers discover surprising clutch of hydrogen clouds lurking among
our galactic neighbors
http://www.sciencedaily.com/releases...0508131700.htm

If this is true, then it's making it more and more unnecessary to look
for exotic WIMPs and other such things to explain dark matter, as dark
matter may simply be this invisible gas between galaxies.

Yousuf Khan

Not necessarily--it would be hard to account for the mass necessary
required for the observed dynamics with just undetectable baryonic
matter.

The GBT, because of its enormous size, unique design, and location in
the National Radio Quiet Zone of West Virginia, was able to detect
this signal, which was simply too faint for other radio telescopes to
detect with precision. "The GBT is unique in this regard," said
Lockman.

Astronomers are also interested in these cold, dark regions between
galaxies because there is a great deal of unaccounted-for normal
matter in the cosmos, and a significant fraction may be contained in
intergalactic clouds like the ones observed by the GBT. Further
studies of this region and around other galaxies in our Local Group
(the galaxies found relatively close to the Milky Way) may yield
additional clues as to the amount of hydrogen yet to be accounted for
in the Universe.

Dear Sam Wormley:

On Thursday, May 9, 2013 12:05:49 PM UTC-7, Sam Wormley wrote:
On 5/8/13 7:11 PM, Yousuf Khan wrote:

....
If this is true, then it's making it more and
more unnecessary to look for exotic WIMPs and other
such things to explain dark matter, as dark
matter may simply be this invisible gas between
galaxies.

Not necessarily--it would be hard to account for
the mass necessary required for the observed
dynamics with just undetectable baryonic matter.

http://www.spitzer.caltech.edu/news/...Lonesome-Stars

No, it seems to me, we just need to look in the Dark to avoid seeing Dark Matter. Because each new way we look we see more normal matter than expected.

http://www.dailymail.co.uk/sciencete...tar-orbit.html
http://www.livescience.com/22852-bla...telescope.html
http://iopscience.iop.org/2041-8205/756/1/L8/

Dark Matter is a placeholder for ignorance. There is *nothing* to it, that observation cannot fix.

David A. Smith

In article ,
Yousuf Khan writes:
Astronomers discover surprising clutch of hydrogen clouds lurking among
our galactic neighbors
http://www.sciencedaily.com/releases...0508131700.htm

If this is true, then it's making it more and more unnecessary to look
for exotic WIMPs and other such things to explain dark matter, as dark
matter may simply be this invisible gas between galaxies.

You need to be quantitative here. Just how much mass are these "new"
clouds adding compared to, say, the mass of stars in galaxies? How
does that compare to the mass of dark matter?

Remember that stars are only a small fraction of baryons, and all the
baryons together are about 1/6 of all the matter.

--
Help keep our newsgroup healthy; please don't feed the trolls.
Steve Willner Phone 617-495-7123
Cambridge, MA 02138 USA

On 10/05/2013 1:05 AM, Sam Wormley wrote:
Not necessarily--it would be hard to account for the mass necessary
required for the observed dynamics with just undetectable baryonic
matter.

Hard to say, if this much matter was found essentially just under our
noses, then they must be everywhere and we just can't see it.

Yousuf Khan