Student Discovers the Universe's Missing Mass

[Tritio]

Many college students spend their summers playing sealing envelopes in office or drinking beers on beaches. Then of course, some like to help others so they do service work in Africa or help inner city kids get ahead in school. One Australian 22-year-old went ahead and located the mysterious intergalactic mass has astrophysicists have spent years searching for. During a summer internship with researchers at the University of Melbourne, undergraduate student Amelia Fraser-McKelvie found the missing matter that scientists have long known to remain from the early history of the universe. "There is missing mass, ordinary mass not dark mass ... It's missing to the present day," astrophysicist Kevin Pimbblet told AFP. "We don't know where it went. Now we do know where it went because that's what Amelia found."

According to an Agence France-Presse report: "Fraser-McKelvie, an aerospace engineering and science student, was able to confirm after a targeted X-ray search for the mystery mass that it had moved to the filaments of galaxies, which stretch across enormous expanses of space." The breakthrough discovery will be published the Monthly Notices of the Royal Astronomical Society and likely lead to improved telescope technology.

Congratulations, Amelia! For the rest of you young interns, back to licking envelopes.

The paper in question is available at the Cornell University Library and can be downloaded via a link on the right. Unfortunately, I do not understand the study (which is rather technical in nature). Can anyone translate it into plain English?

[CaptainChewbacca]

Basically, she determined that filaments had more mass than previously thought and this mass was enough to account for the heretofore 'missing' matter thats baffled most of astrophysics and cosmology.

The article irritates me, though, because its another 'hurr hurr layman beats scientists!' like we've seen before. What this 'intern' actually did was use some very sophisticated equipment as guided and compile the data along with a lot of OTHER data which other scientists gathered, and draw a conclusion.

[kaeneth]

....

The article irritates me, though, because its another 'hurr hurr layman beats scientists!' like we've seen before. What this 'intern' actually did was use some very sophisticated equipment as guided and compile the data along with a lot of OTHER data which other scientists gathered, and draw a conclusion.

You are assuming the journalists understand it well enough to explain it properly. Writing a story about 'hurr durr laymen wtfpwns the entire scientist community!!!' seems easier. Maybe that is just my cynicism and low opinion of my fellow man talking tho.

[Dillon]

Basically, she determined that filaments had more mass than previously thought and this mass was enough to account for the heretofore 'missing' matter thats baffled most of astrophysics and cosmology.

The article irritates me, though, because its another 'hurr hurr layman beats scientists!' like we've seen before. What this 'intern' actually did was use some very sophisticated equipment as guided and compile the data along with a lot of OTHER data which other scientists gathered, and draw a conclusion.

That kind of attitude is pretty common. I feel it's probably a result of the insecurities present in many due to the fact can't begin to understand the ideas of their intellectual betters. Like scientists.

Anyway, if I understand correctly, it looks like this could be the end of dark matter. Or at least, it would mean that there is a lot less of it than previously thought. Pretty amazing stuff.

[PeZook]

That kind of attitude is pretty common. I feel it's probably a result of the insecurities present in many due to the fact can't begin to understand the ideas of their intellectual betters. Like scientists.

Except that she is a science student...so, not a layman.

[Tritio]

...The article irritates me, though, because its another 'hurr hurr layman beats scientists!' like we've seen before. What this 'intern' actually did was use some very sophisticated equipment as guided and compile the data along with a lot of OTHER data which other scientists gathered, and draw a conclusion.

Indeed. If you take a look at it; the article seems very technical and detailed. Not at all at the same level as a "envelope licking intern". The journalist probably couldn't understand it either.

[Darth Tanner]

So as a real uninformed layman does this mean dark matter theory is dead as it’s no longer required to make up for the missing mass? If so how does this change our view of the universe? What does electron density mean however, that the elemental makeup of the universe is heavier than we expected, hence older?

I really don't see how the intern can be viewed as a layman however.

[CaptainChewbacca]

That kind of attitude is pretty common. I feel it's probably a result of the insecurities present in many due to the fact can't begin to understand the ideas of their intellectual betters. Like scientists.

Except that she is a science student...so, not a layman.

Which is why they specifically called her an 'intern' as many times as they could instead of 'Grad Student' or 'Doctoral Candidate' which would also be true.

[Darth Yoshi]

I don't think this really affects dark matter. A quote in the linked article makes a distinction between what was being studied and dark matter. Also, dark matter is theorized to be mostly non-baryonic, while the abstract of the study suggests that what was studied was baryonic.

[Dillon]

That kind of attitude is pretty common. I feel it's probably a result of the insecurities present in many due to the fact can't begin to understand the ideas of their intellectual betters. Like scientists.

Except that she is a science student...so, not a layman.

I was referring to the writer of the article...

I don't think this really affects dark matter. A quote in the linked article makes a distinction between what was being studied and dark matter. Also, dark matter is theorized to be mostly non-baryonic, while the abstract of the study suggests that what was studied was baryonic.

It is true that dark matter was theorized not to form baryons and atoms and such like normal matter as I recall, but from what I understand, dark matter was mainly invented to explain galactic rotation which was completely inconsistent with the amount of mass observed. That required either a complete reworking of the laws of physics or inferring that there was mass that we couldn't see. If these galactic filaments indeed contain far more mass than originally thought, then this would eliminate the need for dark matter, or would at least mean it constitutes a much smaller percentage of galaxies than originally thought. I am not an expert by any means, but this is my limited understanding. If anyone knows better, feel free to correct me.

[Johonebesus]

According to this blog post by a physics professor, this discovery doesn't have anything to do with dark matter.

[Losonti Tokash]

That kind of attitude is pretty common. I feel it's probably a result of the insecurities present in many due to the fact can't begin to understand the ideas of their intellectual betters. Like scientists.

Except that she is a science student...so, not a layman.

Which is why they specifically called her an 'intern' as many times as they could instead of 'Grad Student' or 'Doctoral Candidate' which would also be true.

Except the article clearly states she is an undergraduate, so neither of those descriptors would be accurate.

[GrandMasterTerwynn]

...The article irritates me, though, because its another 'hurr hurr layman beats scientists!' like we've seen before. What this 'intern' actually did was use some very sophisticated equipment as guided and compile the data along with a lot of OTHER data which other scientists gathered, and draw a conclusion.

Indeed. If you take a look at it; the article seems very technical and detailed. Not at all at the same level as a "envelope licking intern". The journalist probably couldn't understand it either.

It's clear that the 'journalist' who wrote the newspaper story doesn't understand a lot of things. For example, it's clear that he never got through the first sentence of the abstract.

Even a naive read of the abstract would've told him that the scientific community already knows that the baryonic matter of the universe is locked up in galaxy filaments. What the paper in question attempts to do is measure the properties of said matter. This is just the sort of project you hand over to doctoral candidates, graduate students, and undergraduate lab interns, since it involves trolling through mind-numbing quantities of data.

And it's not like the undergrad in question did it all herself. She had lots of help. The two other co-authors of the paper are extensively cited in quite a few other scientific papers.

[Serafina]

So basically this was just a more exact measurement of the mass of galactic filaments.
Hardly a radical breakthrough, but that's why we need more scientifically literate journalists.

[Fingolfin_Noldor]

I do my best as a person with a bachelors in Physics to avoid reading pop sci news for the simple reason that most of it is poorly written trash.

If you so much as want a decent "pop sci" magazine, read Scientific American, or one of the general journals from the various reputable scientific organizations, such as Physics Today from the American Physical Society.

Last but not least, it's arxiv. Any tom dick and harry moron could upload crap up there.

[Haruko]

As a layman (read: mediocre at mathematics and science; i.e., dumb) who recently read an essay by K.C. Cole about physicist Janet Conrad, I have a question: Does this have anything to do with neutrinos? That is the first thing that came to mind when I read "'missing' mass" in the universe.

[Serafina]

As a layman (read: mediocre at mathematics and science; i.e., dumb) who recently read an essay by K.C. Cole about physicist Janet Conrad, I have a question: Does this have anything to do with neutrinos? That is the first thing that came to mind when I read "'missing' mass" in the universe.

Based on the blog-post above, neutrinos DO account for a very, VERY small amount (about 0.1%) of the non-observable mass of the universe. Only about 0.4% of the mass of the universe are visible phenomena like stars. About 3.6% are intergalatic gas, and about another 0.1% are supermassive black holes, rogue planets (jupiter-like objects) and so on.

That still leaves us with ~96% of the mass of the universe unaccounted for. The mass of galactic filaments is a tiny, tiny drop in a giant ocean that does in no way eliminate the need for dark matter&energy in order for the universe to make sense.

[Dillon]

I do my best as a person with a bachelors in Physics to avoid reading pop sci news for the simple reason that most of it is poorly written trash

Yeah, lesson learned on my part. When an article is titled "Student Discovers the Universe's Missing Mass", that seems pretty deceptive, especially when I've heard the term "missing maass" used to refer to dark matter many times.

[starslayer]

As a layman (read: mediocre at mathematics and science; i.e., dumb) who recently read an essay by K.C. Cole about physicist Janet Conrad, I have a question: Does this have anything to do with neutrinos? That is the first thing that came to mind when I read "'missing' mass" in the universe.

Not really. Neutrinos have very small masses, and do account for some of the non-baryonic mass in the universe, but not all that much, and they aren't generally trapped in any gravitational well. Almost all of them are relativistic particles, and are grouped with photons from a cosmological point of view. This paper concerns the free electron density in filaments of galaxies, so it is entirely about baryons. As Terwynn pointed out, we basically already knew where the baryons we couldn't account for were from computer simulations (also see the first couple sentences of the introduction); the observations here just prove it. Still, good for the student to get a first author paper as an undergraduate.

Last but not least, it's arxiv. Any tom dick and harry moron could upload crap up there.

That's true, but this paper's pretty obviously been sent in for publication (see the MNRAS header on the paper itself).

Oh, and another note: No, this paper does not obviate the need for dark matter in any way, shape, or form. The density of these electrons is very low, and cannot possibly account for galactic rotation curves.

[Sriad]

Correct me if I'm misreading the paper; I'm working from an "advanced layperson" level.

At best this paper raises the total % of stuff in the universe made of baryonic matter from about 5% to maaaaybe 8% by demonstrating that intergalactic filaments aren't straight lines running from galaxy to galaxy, but instead tangles that need much larger observational "boxes" than have typically been used to fully observe. The diagrams at the end of the actual Cornell paper Tritio linked show this without much need for advanced understanding: a straight line between two galaxy clusters contains encases only a small fraction of the filament. It's likely the most dramatic example but it demonstrates the point very persuasively, especially because it's a filament that was previously classified as "straight".

The physicists saying things like "this is where the dark matter went" PROBABLY mean that the filaments attract a lot of dark matter; we haven't found enough from gravitational lensing, so the fact that filaments have a lot more mass than we thought means there's a LOT more dark matter hanging out between galaxies than we thought, and much a much lower % in the dark matter galactic "halos" we're used to thinking of.

[ArmorPierce]

[Anyway, if I understand correctly, it looks like this could be the end of dark matter. Or at least, it would mean that there is a lot less of it than previously thought. Pretty amazing stuff.

It looks like the article specifically made reference that this is matter outside of dark matter to me.
quote]"There is missing mass, ordinary mass not dark mass .[/quote]

[starslayer]

The physicists saying things like "this is where the dark matter went" PROBABLY mean that the filaments attract a lot of dark matter; we haven't found enough from gravitational lensing, so the fact that filaments have a lot more mass than we thought means there's a LOT more dark matter hanging out between galaxies than we thought, and much a much lower % in the dark matter galactic "halos" we're used to thinking of.

No physicist has said anything of the kind; they all refer to the missing baryons. Of course, the way cosmologists use the term baryons is similar to the way they use metal: electrons are typically included, even though they're actually leptons, not baryons. Dark matter is entirely separate from this.

[Sriad]

Oops, you're right. I totally misread '"There is missing mass, ordinary mass not dark mass ... It's missing to the present day," astrophysicist Kevin Pimbblet told AFP. "We don't know where it went. Now we do know where it went because that's what Amelia found."'