Has the Missing 80% of the Universe’s Mass Been Found?

The search for dark matter — the glue that holds the cosmos together — takes a big step forward

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NASA / ESA / University of California, Santa Cruz / Leiden University / HUDF09 Team

The universe has never made things easy: every time you look away, it becomes bigger, stranger, curiouser. And that’s only the part we can see. As you might have heard if you pay attention to these things (and will be distressed to learn if you don’t), up to 80% of the matter in the universe is simply missing. The Milky Way spins so fast it would fly apart if the gravity of some invisible matter weren’t holding it together. Clusters of galaxies, buzzing around one another like angry bees, would similarly fragment and disperse. And when you run the gravitational numbers, the mysterious matter that keeps all that cosmic disintegration from happening should outweigh the familiar stuff by about 4 to 1.

(PHOTOS: Window on Infinity: Month in Space)

It was in the 1930s that astronomer Fritz Zwicky first proclaimed — to general skepticism — that what is now known commonly as dark matter must exist, surrounding most galaxies like a glass paperweight surrounds a butterfly. But not only could physicists not detect the material, they couldn’t even agree on what they should be looking for. Dark matter thus became as much an article of cosmological faith as of well-established theory. Now it appears that faith may have been rewarded. Just as researchers working at Europe’s Large Hadron Collider last year announced that they had bagged the Higgs Boson, so did investigators this week reveal that they’ve found compelling evidence for a type of theorized particle known as a WIMP — for weakly interacting massive particle — and that at least one form of it may be the dark quarry they’ve been hunting for 80 years.

(PHOTOS: Mars on Earth: A Look at the Mars Desert Research Station in Utah)

The new findings come from a team of physicists led by Samuel Ting, of the European Organization for Nuclear Research, relying on data gathered by the Alpha Magnetic Spectrometer (AMS), a detector delivered to the International Space Station in 2011. The purpose of the AMS is to sift incoming cosmic rays — streams of high energy pouring in from outside the solar system — for unusual particles. Dark-matter particles, if they exist, might also get mingled into this cosmic flow, but theories suggest they’d be hard to spot. They can pass through ordinary matter as if it weren’t there (billions could be streaming through your body as you read these words) and they’d be utterly invisible to any sort of telescope.

(MORE: Scientists Find Universe Is 80 Million Years Older Than They Thought)

If we can’t detect dark matter itself, however, we might detect its byproducts. Theorists think that when two dark-matter particles meet out in space, they’ll occasionally, albeit not often, destroy each other in a tiny burst of energy. That energy would then condense back into entirely different particles: an ordinary electron and its much rarer antimatter counterpart, a positron, which would go speeding away from each other in some random direction.

It’s these positrons that AMS detected — some 400,000 of them in the nearly two years it’s been in operation. The number and energy of the positrons is consistent with what theorists would expect if dark matter really is smashing into itself throughout the Milky Way. So is the fact that the positrons are hitting the detector from all directions, which it should if dark matter truly pervades the Milky Way. Says Jeremiah Ostriker, a Princeton astrophysicist who has been in the forefront of dark-matter theory since the 1970s, “The AMS experiment may — just may — have detected [evidence of] dark-matter decay.”

(MORE: Where in the Universe Is Voyager? The Surprising Showdown Over Where the Solar System Ends)

Ostriker’s caution, and that of the AMS team at a press conference on Wednesday, is understandable, and not just because the evidence is indirect — like spotting bear tracks instead of the bear. Dark-matter collisions, the scientists acknowledge, are not the only possible source of positrons. They could be streaming off of spinning pulsars, the superdense remnants of exploding stars that also pervade the Milky Way. Their ubiquity would send positrons to us from all directions just the way dark matter would. And even if the pulsars aren’t responsible, says Ostriker, whose new book, Heart of Darkness, chronicles the history of dark-matter research since the very beginning, the positrons “could come from some other strange source” that astronomers haven’t thought of yet.

It’s a good thing, therefore, that the AMS will keep operating for several more years, at least: the more positrons it can find, the firmer the case could become that their source really is dark matter, and physicists might even be able to reason backward and infer the nature of the original particle itself. If AMS really does crack the mystery, Ting, who won a Nobel Prize in 1976 as a co-discoverer of a particle known as the J/psi meson, could well snag another. But he knows better than anyone that it’s a bit too early to start drafting the acceptance speech. The universe may give up its secrets eventually — but it never, ever does so easily.

MORE: A Super-Telescope Goes to Work

28 comments
szeldich
szeldich

The problem with a Dark Matter could be in the way how the luminosity of a group of stars calculated. The incoming energy will never retransmitted by a star, so the luminosity of a dense group of stars is much lower than the sum of they luminosities.

We are living in the shades of stars.

sekhar
sekhar

Can black matter or black holes absorb TIME?

Rajpal
Rajpal

More energetic than the cosmic gamma photons, there should exist dark photons and Planck photons. Dark photons may be the particles of the elusive dark matter.

http://vixra.org/pdf/1303.0207v1.pdf

What is Dark Matter?

fivish
fivish

Dark matter and energy are mathematical construct necessary to make the Big Bang theory work. Rather than admit that the BBT is wrong they add fudge factors, huge ones, with absolutely no justification. If you then go look hard enough and throw enough money at it of course you will find what you are looking for! Did they not fudge the BBT theory for a CBR of 2.7K when it should have been 50K? The mathematicians are ruining science. Shame on them.


Read more: http://science.time.com/2013/04/05/has-the-missing-80-of-the-universes-mass-been-found/#ixzz2RIwFuNaA

blubenz1959
blubenz1959

The print version of this article included a pie chart showing ordinary matter at 5%, Dark matter at 27% and Dark energy at 68%. Am I the only one wondering what happened to all of the ordinary energy in the universe? I guess it's cooler to think about dark matter and energy, whose existence hasn't been proven than to consider "ordinary" energy. Perhaps when we figure out how the universe we can detect creates such forces as gravity and other vaguely understood concepts, we can spend time chasing down the "Dark" side.

jozue06
jozue06

"Curiouser " ...? C'mon.

NickyGrahams1
NickyGrahams1

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thewholetruth
thewholetruth

God is laughing at our stupidity in trying to figure out the Universe

YehudaElyada
YehudaElyada

A part of the problem of making cutting-edge science intelligible to commons is the strange habit of scientists to use suggestive, whimsical idioms to nomenclature deep, non-intuitive ideas that are really paradigm shifting. Thus we were exposed to “Black Holes”, “God’s particle”, “Big Bang” and “Quantum Jumps” to name just a few physics concepts. Dark matter is one more from the latest crop of misleading (to non-pros) idioms. As biological machines, we are used to “see” things that exist physically in the dimensions relevant to Natural Selection. (Even this ability is not perfect, i.e. we can’t see microbes, nor detect radioactivity with our natural senses). Therefore, commonsense has a problem to accept the simple fact that, more than 50 years ago the existence of a “dark matter-like” particle was experimentally proven, (the Neutrino, more that 25 years after its existence was postulated by W.E. Pauli). There is nothing “witchcrafty” about the “darkness” of certain elementary particles, because there is nothing “Devine” in our limitation to sense only Electro-Magnetic signals. Particles that do not participate in EM interactions are invisible to our eyes, but not dark in the usual meaning. Conventional darkness relates to the absorption of light (EM radiation) by EM-active material (black matter). Other senses - audio, smell/taste, tactile, temperature - are also dependant on EM interaction to register. So Dark Matter is not just transparent, it’s unobservable. Other than this characteristic, dark matter is as Normal as any common material entity. We just have to accept the idea that our eyes do not see everything there is.

Robinson.W.Marte.R
Robinson.W.Marte.R

En este artículo se lee este párrafo: "If we can’t detect dark matter itself, however, we might detect its byproducts. Theorists think that when two dark matter particles meet out in space, they’ll occasionally, albeit not often, destroy each other in a tiny burst of energy. That energy would then condense back into entirely different particles: an ordinary electron and its much rarer antimatter counterpart, a positron, which would go speeding away from each other in some random direction."

Luego en el párrafo siguiente leemos esto: "It’s these positrons that AMS detected — some 400,000 of them in the nearly two years it’s been in operation. The number and energy of the positrons is consistent with what theorists would expect if dark matter really is smashing into itself throughout the Milky Way. So is the fact that the positrons are hitting the detector from all directions, which it should if dark matter truly pervades the Milky Way."

Ocurre que el Universo tiene 13,700 millones de años, y la Vía Láctea tiene 13,200 millones de años: ¿adónde diablos se han ido todos los electrones que durante 13,700 millones de años se han estado produciendo por la interacción de las supuestas partículas de la Materia Oscura? Si ciertamente el AMS está registrando los positrones que resultan de la interacción de partículas elementales de la Materia Oscura entonces es lógico pensar que esas partículas se están "materializando": ¿qué significa eso?

Si esa interacción de la Materia Oscura está produciendo positrones a ese ritmo: ¿porqué la Vía Láctea completa no muestra la interacción de su materia "bariónica" con esos positrones?, o, ¿se puede detectar el choque de esos positrones (antimateria) con la materia de la Vía Láctea? ¿Qué ocurre con los electrones formados por la interacción de las partículas elementales de la Materia Oscura?, ¿se cancelan con los positrones también así formados?, ¿porqué no se nota esa masiva ¿? anulación de los positrones en todo nuestro "espacio" circundante?, ¿se podría detectar la interacción de esos positrones con la materia de la que está compuesta la Vía Láctea? 13,200 millones de años de interacción de la galaxia con la Materia Oscura, de este modo, con el resultado del choque de sus partículas elementales, ¿en términos cuantitativos, qué significaría todo ese tiempo ocurriendo ese fenómeno?, ¿qué radiación, en 13,200 millones de años, habría emanado de la Vía Láctea por la interacción con la "antimateria" creada por las partículas de la Materia Oscura? :(  

rohit57
rohit57

We have found the missing 80% of the universe and it turns out, it speaks Mandarin (smile).

DeweySayenoff
DeweySayenoff

I can't help but wonder about people.  In another recent news article, someone thought they saw a sign from God in a Goldfish cracker (It had obviously come into contact with a Phillips head screw on the edge of a machine and someone likely tossed it back into the batch, or it fell back in).  In this article, scientists gush about how these findings help bolster Dark Matter - or not.

The universe is a very energetic place.  It's been around a long, long time.  Dark matter's qualities are based almost entirely on conjecture, and unfortunately that conjecture includes evidence of other things we already know a lot about that have nothing to do with dark matter.  So while they found stuff they call evidence of dark matter, it's going to take a hell of a lot more to "prove" dark matter exists since this evidence has other well known explanations as well.

John
John

I usually read anything posted on the dark matter topic, because they interest me, but what I see in this article seems to be a repackaged version of earlier articles with a few slightly new conjectures.

This appears to be one of those "the answer is just over the next hill" articles, with no imminent resolution, but which promises a virtually limitless number of additional articles on the subject when it is a slow science news week.

TimWhiteheart
TimWhiteheart

The heavens declare the glory of God and the firmament showeth forth His handiwork. Enough said.

hockeytownboy
hockeytownboy

Yet they still haven't solved the ancient conundrum of did you drop your chocolate in my peanut butter, or is it my peanut butter in your chocolate? Cause of multiple wars throughout the ages.

alienamonghumans
alienamonghumans

I cannot be the only one who noticed this . . . the cover image that links to this article, look closely. Either someone has messed with that image, or there is a clear depiction of a child's head from the shoulders up in this NASA photo.

meropin
meropin

For unprofessional people, like me, the only image which can be depicted is a vision that something dark and big ameba-like thing intently hold cosmic world together. And it is valuable that I can have a new image of shebang of universe like this.

PhilipWilson
PhilipWilson

Theory says DM should be a spherical halo enveloping the flattened spiral disk that is the Milky Way galaxy.  Therefore putative DM collisions should come equally from all directions.  But pulsars, the remnants of massive stars that went supernova, are ordinary baryonic matter and their parent stars should show an overwhelming statistical bias towards the plane of the Milky Way.  Therefore their positron emissions would not be omnidirectional.  If the detected positrons are extragalactic coming from galaxies all over the universe, this quandary is resolved.  So, are the positrons "local" i.e. from our Milky Way or can/are they detected from throughout the universe?

duduong
duduong

I am glad to see that a science correspondent at Time can give an accurate description of this new development, largely free of hype. During the past 3 decades, string theorists' shameless and self-contradictory hypes have turned particle physics into a laughing stock. Fortunately, Mr. Lemonick took care not to quote any string theorists (e.g. Brian Greene) and thus spared us more nonsense.

The positron signal, as the article pointed out, does not have to come from Dark Matter. Nobody knows how many positron sources contribute to the background, much less what the background should look like. Without the ability to filter out the background, "discovering" Dark Matter through positron signal is little more than a pipe dream. 

AMS itself was originally designed to test some of the more crazy ideas back in days when string theorists were promising the imminent discovery of various string-inspired phenomenology and some sane people still took them seriously. Over the next 18 years, it became harder and harder to justify the multi-billion-dollar price tag on ungrounded speculations of a cult that was gradually discredited by the science community. Dark Matter's discovery thus becomes the perfect excuse to continue to the project.

I wish prof. Ting good luck, because the particle physics community really needs a boost to recover from string-inflicted damage to the field. Otherwise, a field that was founded by giants like Dirac and Einstein may end up becoming another branch of astrology.


SwiftrightRight
SwiftrightRight

@fivish Do you even know what your saying when you type "fudge the BBT theory for a CBR of 2.7K when it should have been 50K"

SwiftrightRight
SwiftrightRight

@thewholetruth So what exactly is your theological backing for believing that God would be laughing at us for "trying to figure out the Universe?"



steelgoat67
steelgoat67

Woe, the folly of man. When will it ever end?

sekhar
sekhar

May be in one of the black holes!!!!!!!!