Using our Keck Telescope atop Mauna Kea, astronomers have found that elliptical galaxies contain many more red dwarf stars than previously though. Ellipticals are some of the largest galaxies, containing around a trillion stars each. Red dwarfs, being small and dim, are particularly difficult to detect in other galaxies. The new results indicate that the Universe might have 3 times as many stars as previously thought. This affects estimates of how much dark mass is needed to fill the Universe. Galaxies might need less dark stuff than previously thought in order to be stable. CfA Press Release.
A red dwarf could greatly affect life on Earth. In 1984 Richard Muller and others proposed that Nemesis, an unseen companion to our Sun, might cause mass extinctions. By this hypothesis, the unseen Nemesis orbits into the Oort Cloud of comets every 27 million years, causing comets to spiral toward the inner solar system. In 1999 John Matese and Daniel Whitmire, using comet observations, made a similar hypothesis. The hypothetical object could be a brown dwarf, slightly larger than Jupiter, or a larger red dwarf.
The inky black of empty Space is far from empty. Today it is thought to be home many more red dwarf stars than once thought. It could also contain brown dwarfs, objects like Jupiter, in unknown numbers. Potentially Space could also contain primordial Black Holes, some of which form the cores of larger objects. One of these objects, orbiting our Sun, could cause the mass extinctions on Earth. There is far more in the Universe than meets the eye.
The UNESCO palace, site of the "Invisible Universe" conference, is across from Ecole Militaire and within sight of the Eiffel Tower. Today there was time for a visit to the War Museum and Napoleon's tomb between talks. Last night I shared a table with Mordecai Milgrom and his wife. This afternoon Milgrom gave a 45-minute talk on MOND, modified Newtonian gravity.
While scientists since Fritz Zwicky and Vera Rubin have looked for "dark matter," Mordecai and colleagues have been developing MOND as an alternative for the last 25 years. Since DM has never been directly observed, the field is open to alternatives. He claims that MOND can match the predictions of DM. The theory is far from complete, Milgrom admits, but today he was able to present before an international audience.
Though they sound similiar, "dark matter" and "dark energy" would be quite different if they both existed. One would attract and the other repel. They possibly share the quality of being misnamed. DM could be made of Black Holes that have never been matter at all. DE can be explained by a changing speed of light. They are both inferences that have never been directly observed.
One of Mordecai's slides had an interesting equation: a ~ cHo This is remarkably similar to R = ct, suggesting that they are on to something. (Thanks to nige for pointing out the correct form, which he has pointed out before.) It is good that alternative ideas are being heard.
According to Space.com, astronomers have discovered a mysterious Dark Flow. Giant clusters of galaxies appear to be moving at high speed toward a mysterious source of gravity. No known gravitational source can account for this massive flow. We have long known of a hidden "Great Attractor" pulling galaxies toward it. The mass causing this Dark Flow must be even more enormous.
In this picture from the Cosmic Microwave Background, white spots are moving clusters of galaxies. They are all being drawn toward the small region marked in violet. Since there is no visible source of mass, scientists are speculating that the mass is outside the visible Universe! They should consider this: perhaps the source of attraction is truly dark, an ultra-massive Hole in Space.
"Expansion of the Universe is not uniform. Individual motions of galaxies can oppose the Hubble flow, like trout swimming upstream. The Milky Way and thousands of other galaxies are falling at 600 km/sec toward an unseen mass called the Great Attractor. This object has the mass of 10^16 Suns or 100,000 galaxies! It may be a true Black Hole, so monstrously massive that nothing can escape. There is evidence of another Great Attractor some 700 million years away.
"These monsters could be common, yet they are not counted in mass surveys. The missing 2/3 ascribed to "dark energy" may be hidden from us. It is foolish to think that humans know all that is out there. That is like Wile E. Coyote, Super Genius not realising that he is falling into an abyss.
"A physicist can go with the flow, avoid risk, and not stand out. One can profess that the Universe is dominated by "dark energy" and the Sun circles the Earth. Such people end up complaining about their unsatisfying lives because they never make a difference. It is much more fun to stir things up!
Models can predict the 71.62% proportion of this dark mass. This is precisely the amount found by the WMAP spacecraft. Because the early speed of light was much larger, primordial Black Holes formed to immense size. These ultra-massive Holes cleared immense dark voids in Space. Today they would invisibly attract galaxies toward them, exactly as has been observed. This is one more indicator of a changing speed of light.
Astronomy is abuzz with discovery by 25-year old Hanny van Arkel of a galaxy unlike any ever found. The Dutch schoolteacher found this strange object while participating in the Galaxy Zoo. This project invites anyone to classify galaxies from the vast Sloan Digital Sky Survey database. Hanny will likely be named a co-discoverer, increasing respect for "amateur" astronomers.
This hot green ring of gas is a starless galaxy, radiating from an unseen energy source. The object radiates with a greater intensity and temperature than could be accounted for by normal means. The central void in this object would be an excellent placed to seek a Black Hole. There could be many more dark objects out there. The 71.62% of the Universe ascribed to "dark energy" may be hidden in the voids.
Chen Shi-Zheeng, director of operas and the movie DARK MATTER. Chen was inspired by a 1991 incident at University of Iowa, when a physics grad student from China killed 5 colleagues and himself. An innocent woman named Miou had been assigned to the physics department as a pool secretary, and was caught in the crossfire. She was severely injured but survived to enjoy the movie Saturday.
Chen noted that at least 1000 suicides occur each year on campus (more Americans than are killed in Iraq). For some reason the schools don't tell our parents about this, or the many assaults and crimes against women. Along with all the other hazards, there is great pressure for us young minds to conform. Anyone on physics will tell you how difficult it is to propose new ideas. After the New York screening of DARK MATTER, astrophysicist Neil Tyson stood up and said, "that's the way it is!"
Each individual life is valuable, and you may note some additions to the blogroll. Long overdue for a link is Carl Brannen, who singlehandedly has come up with some fascinating ideas about masses and "snuarks." He has noted that if c ~ t^{-1/3} and R(t) ~ t^{2/3}, we could just as easily write c(t) = R/t. Black Hole radius, Planck length, wavelength of photons and even the scale of magnetic fields would also vary proportionately to R. Keep up the good work, Carl!
We are fortunate to have heard from Robin Booth. As an MSc student at Imperial College he had Joao Maguiejo as supervisor and heard many things about a changing speed of light. His paper has many parallels with other research on "c change." Expect to hear many good things about Robin's work. Look for his link "Insular Institute." (slow download)
Carl and Paul Nielson also point out a paper by Alexander Unzicker, which reexamines Dirac's large number hypothesis. Paul Dirac, one of the biggest names in quantum mechanics, noticed some strange coincidences in the fundamental values. Putting c ~ t^{-1/3} neatly solves Dirac's mystery, something even a hostile questioner at St. Louis noticed.
Robin reminds us that the Alternative Cosmology Group, is having their conference September 7-11 in Port Angeles, Washington. The location is a national forest at the entrance to Puget Sound, across the strait from Victoria BC. Sometimes a walk in the woods is the best way to find new insights. One can also observe salmon swimming upstream! Carl, Robin and others show that real breakthroughs come from outside the mainstream.
Controversy about Dark Matter has been with us at least since Fritz Zwicky in the 1930's. From motions of the Coma Cluster in Berenices, Zwicky deduced the existence of unseen mass. His eccentric manner earned Zwicky much derision from colleagues, whom he called "spherical bastards" because they appeared that way from any direction. Astronomer Vera Rubin saw spherical haloes of dark matter in the rotation curves of galaxies. On the way she probably encountered challenges to women and to new ideas, dark matters which have always been with us.
Argument about this unseen mass continues to this day. An alternative theory called Modified Newtonian Dynamics (MOND) has been championed by Mordecai Milgrom since the 1960's. Recently observations of the Bullet Cluster seemed to confirm the Dark Matter's existence, but MOND advocates quickly found a way to make observation fit their theory. Argument exists whether Dark Matter is composed of Black Holes, undiscovered particles, old AOL disks, something else or a combination.
DARK MATTER is a film by opera and theatre director Chen Shi-Zheeng. Liu Xing (Shooting Star) arrives at an American PhD program with plans to study the Universe. His talents get him accepted into the cosmology group by department head Aidan Quinn and wealthy patron Meryl Streep. He accompanies his professor to a cosmology conference and comes up with an original Theory about Dark Matter.
Liu clings to belief that science is a free market for ideas. Unfortunately his Theory conflicts with the professor's model and the hierarchical university system. After being warned against pursuing his idea, Liu publishes on his own. The paper is derided, his dissertation is rejected, and Liu finds himself unemployed in a strange land. His frustrations explode in a graphically violent end. The movie was inspired by a University of Iowa physics department meeting in 1991, when a grad student killed five colleagues and himself.
DARK MATTER the movie was completed a year ago, but sat on the shelf because of the Virginia Tech tragedy. (The campus had been declared a gun-free zone, which didn't discourage the lunatic from mowing down 32 defenseless people.) Some of us women have encountered opposition from professors who possibly didn't need to be around. Having enjoyed similiar experiences, one can say that there are better ways than violence. Better to let them live long enough to see how wrong they were.
The exact amount of Dark Matter can be predicted from pure math. It is 23.87%, exactly matching the WMAP findings within half a standard deviation. Theory also provides big clues to what the Dark Matter really is. The amount of baryonic matter can also be predicted as 4.507034%, also matching WMAP within half an S.D. When a prediction fits the data this closely, perhaps someday more people will take notice. Until then, it is fun asking lecturers about the 4.507034% and seeing their befuddled reaction.
The Pioneer spacecraft gave us a first glimpse from the outer Solar System. Pioneer 10 was launched March 3, 1972 and encountered Jupiter in December 1973. Its last weak signal was received in 2003, as it headed for interstellar Space. Pioneer 11, launched April 6, 1973; flew by Jupiter in December 1974. This spacecraft then used the Jupiter's gravitational field to slingshot toward a Saturn encounter on September 1, 1979. Last communication with Pioneer 11 was in November, 1995. The two spacecraft are headed in different directions--Pioneer 10 toward Aldebaran and Pioneer 11 toward the constellation Aquila. They carry the famous plaque designed by Carl Sagan. Signals from the Solar System's outer reaches led to the mysterious Pioneer anomaly.
According to radio Doppler data, both Pioneers show a constant sunward acceleration of 8.74 x 10^{-10} meters per second-squared. Interest is slowly growing in this anomaly. Possible sources of systematic error have been accounted for and the acceleration is still there. Presently the archived data is being examined even closer to see if this effect is really sunward or Earth-centred. An error is still possible, so resolution of this issue may have to await better data. Though Voyager 1 has ventured further, that spacecraft is not spin-stabilised and can not corroborate the anomaly. Data from another Space mission may be needed.
For this article we will assume that the effect is real. The problem can be simply explained by inferring that "dark" mass in the Solar System is affecting Pioneer. Data from these spacecraft could indicate density of this mass and how it is distributed. The most important clue is that the acceleration appears to be constant. Gravitational acceleration a is:
a = GM r^{-2}
If mass were distributed spherically, as in the galaxy, mass distribution would be given by: M = $4 \pi \rho$/3 r^{3}. Acceleration a would then be a multiple of r and not constant. If mass were distributed in a disk, we would have:
M = $4 \pi \rho$r^{2}
Now the "r's" cancel out and we have constant acceleration:
a = $4 \pi G \rho $
We can quickly find the density of this mass distribution:
$\rho $= a/$4 \pi G$ = (8.74 x 10^{-10})/[$4 \pi $ (6.67 x 10^{-11})]
$\rho $= 1.04 kg per square meter
Such a disk-shaped mass distribution is not out of the question, since humans know very little about the outer Solar System. Observations of the visible planets and a few probes like Pioneer provide the only data. Recently we have discovered that Pluto is just one of many planet-like objects outside Neptune's orbit. There is far more out there than meets the eye.
We can consider the possibility of primordial Black Holes. The typical mass of such objects is about 10^{12} kg. That is approximately the mass of Uluru (Ayers Rock) in a volume smaller than a proton! We would have approximately one such object per area of 1 million square kilometres. This is about one Uluru mass per area the size of Australia.
Would a Pioneer in the outer Solar System be likely to encounter a Black Hole? Though it is visible for many kilometres, one can spend an entire lifetime in Australia and never see Uluru. A Black Hole's gravitational influence is actually quite small--if you were just 2.6 metres from a 10^{12} kg Black Hole, you would feel no more gravitational pull than you feel at Earth's surface. You could wander an Australia-sized area for a lifetime, and the probability of falling into a Black Hole's influence would be less than the chance of stumbling into Hugh Jackman's bedroom!
If an unseen disk of Black Holes exists, they would not add significantly to the Solar System mass. If this distribution were extended into our neighbourhood, dark mass within Earth's orbit would be only 3.2 x 10^{23} kg. That is negligible compared to the known mass. Earth alone has a mass of 5.98 x 10^{24} kg, and the Sun has a mass over 10^{30} kg. Since Black Holes would be so difficult to find, only the effect of the entire distribution can be detected by Pioneer.
A distribution of "dark mass" is just one idea. Interest in the Pioneer Anomaly has led to many other theories including modified gravity and even changes in the speed of light. (Where have we heard about varying c before?) At present a systematic error is still a possibility. The anomaly is still a fascinating mystery that may point to new physics.
Small dark galaxies have been found surrounding our Milky Way. Since Fritz Zwicky in the 1930's, astronomers have suspected that galaxies are surrounded by hidden mass. Astronomer Vera Rubin reached a similiar conclusion based upon galaxy rotation rates. Theorists have believed that the galaxy is surrounded by hundreds of smaller galaxies. Since these are not visible, it was suggested that the dwarf galaxies are made entirely of dark mass.
Earlier this year astronomers reported on VIRGO H121, a Dark Galaxy. This galaxy could be found found only from its radio emissions. When VIRGO H121 was first noticed back in 2000, the astronomy community was very skeptical. Sometimes a new observation takes years to be accepted.
The dark halo surrounding our galaxy holds many dicoveries. Just one month ago astronomers found a Pulsar in Galactic Halo. Like pulsars within the galaxy, this object gives off rotating beams of radiation like a lighthouse. A pulsar's energy source has been a mystery, but the twin jets are like those given off by a Black Hole.
The dwarf galaxies were originally located using the Sloan Digital Sky Survey. Further observations with our Keck II telescope on Mauna Kea. These galaxies are 10,000 times smaller than the Milky Way. Since mass of the galaxies is 100 times greater than that of the stars alone, there must be further dark mass in their vicinity. Astronomers now believe that hundreds of these dark galaxies surround our Milky Way.
These results will be reported in the November 10 issue of Astrophysical Journal. Because these are distinct from dwarf galaxies, they have been nicknamed "hobbit galaxies." Will there be elf galaxies and orc galaxies?
Since every galaxy contains at its centre a massive Black Hole, it is logical to infer that dark galaxies contain them too. Hundreds of dark galaxies could signal thousands of Black Holes in the galactic halo. There could be still more surrounding the dwarf galaxies. Presence of Black Holes would also explain formation of globular clusters. Our Milky Way could be surrounded by a halo of Black Holes.
In 1967 the first pulsar was discovered by graduate student Jocelyn Bell with her thesis advisor Anthony Hewish. The pulsar's regular radio pulse was at first thought to be a signal from extraterrestrials. Today they are theorised to be rapidly rotating neutron stars sending beams into Space like lighthouses. 40 years after discovery, the source of pulsar's enormous energy has remained a mystery. For their work on pulsars Hewish was awarded a Nobel Prize, Bell was not. (Memo: Leave thesis advisor out of research.) This year Jocelyn Bell was named a Dame of the British Empire.
Caltech astrophysicist Fritz Zwicky was known for speaking his mind. He described certain colleagues as "spherical bastards" meaning they appeared as such from any angle! Zwicky's expertise on spherical matters was unquestionable. In the 1930's he used the Virial Theorem on the Coma Cluster of galaxies to deduce a halo of invisible mass. In the 1970's astronomer Vera Rubin used galactic rotation curves to similiarly conclude that most of a galaxy's mass was dark. Nature of the "dark" mass surrounding our galaxy has long been a mystery.
This year one discovery may shed light on both mysteries. Astronomer Robert Rutledge of McGill University and colleagues have reported Discovery of an Isolated Compact Object at High Galactic Latitude. Object J141256.0+792204 is apparently a pulsar located in our Milky Way's dark halo, approximately 5100 parsecs above the galactic disk. This object was discovered by the ROSAT spacecraft with further observations by SWIFT, the Chandra X-ray Observatory and our Gemini North telescope on Mauna Kea.
A pulsar's twin beams propagate along magnetic field lines. Their axis is independent of the neutron star's spin axis, causing them to be dragged around like lighthouse beams. Some pulsars are magnetars, with magnetic fields too powerful for our physics to describe. Twin beams of radiation and a magnetic field are both signs of a Black Hole.
The Black Hole could not have been created by the neutron star, or even by the supernova explosion that created the pulsar. The singularity must have been there billions of years before, when the progenitor star was first created. How stars collapsed from diffuse gas has also been a mystery. Black Holes provide the missing link to understand star formation.
The Big Bang created billions of singularities. These were formed from tiny quantum fluctuations grown large by expansion of the Universe. Size of a primordial Black Hole is limited by a horizon related to the speed of light. Because c was much higher, PBH's formed in a variety of sizes. The largest formed voids, clusters and galaxies. Smaller Black Holes were drawn to the big ones, creating dark haloes around galaxies. Many times these smaller holes have collided with the galaxy's dusty disk, and we are the result.
A Black Hole colliding with a dust cloud will draw matter to it but not suck everything up. The small amount that is eaten will turn into energy and cause the rest to grown extremely hot. Heat of millions of degrees is the ONLY process that can ignite nuclear fusion and the birth of a star. Infant stars, which astronomers call Herbig-Haro objects, exhibit the twin beams of a Black Hole. While most of the Sun's energy comes from nuclear fusion, the Black Hole is quietly contributing to the star's power output. Presence of the Black Hole caused the Sun to collapse in the first place, and allows it to burn steadily for billions of years.
Our theories of the Sun have advanced over time. As late as the 1920’s most astronomers would lecture that our Sun was made of iron, and glowed in the sky like a hot poker. Only a young astronomer named Cecilia Payne suggested that the Sun’s spectral lines could be interpreted as hydrogen. Because Payne was a woman, her idea was roundly dismissed. The equations of nuclear fusion were still being worked out, and most scientists doubted that Black Holes exist.
Black Hole energy and nuclear fusion are two of many processes occuring inside stars. As our knowledge of physics advances, so must theories of the Sun. Physicists have long sought to produce energy via nuclear fusion. Despite decades of work and billions of dollars, they have been unable to produce a sustained reaction. Hint: You need a Black Hole.
Only occasionally will a Black Hole reveal its presence. If a dying star is over Chandrasekhar's limit of 1.4 solar masses, it will eventually collapse catastrophically. Sudden influx of a star's mass into the Black Hole is the ONLY mechanism powerful enough to ignite a supernova. This titanic explosion rips the outer layers away, leaving behind a small dense remnant, a neutron star. If the Black Hole has enough angular momentum, it will produce a magnetic field and twin jets. Because the jet axis is often different from the neutron star's rotation axis, the jets will rotate through Space exactly as observed. A Black Hole is the ONLY mechanism that could produce twin jets and a magnetic field.
A Black Hole is the ONLY object that can make billions of clouds collapse into stars, the ONLY mechanism that can power a supernova, and the ONLY mechanism that can create the jets and magnetic field of a pulsar. Black Holes could be ubiquitous, from the galactic halo to the interior of our Sun. The 95.49% of our Universe that is not baryons could be dominated by Black Holes.
Discovery of a pulsar in the Milky Way's dark halo may also be seen as discovery of a Black Hole. Ruttledge's team notes that this pulsar in the galactic halo could be the tip of an iceberg. For every Black Hole that can be found by its pulsar jets, there could be many more without jets. The galaxy's invisible halo of dark mass could be filled with Black Holes. There are more things in Heaven and Earth, Horatio, than are dreamt of in your philosophy.
On June 19 this blog reported on discovery of a Dark Galaxy. In addition to hosting the Carnival of Space, Dr. Pamela Gay has just written about Finding Dark Galaxies. In the 1930's Fritz Zwicky suspected that unseen "dark matter" dominated galaxy clusters. Vera Rubin in the 1970's deduced its existence in galaxies from their rotation curves. Now we know that an unknown number of galaxies are completely made of the stuff.
Since DM emits no light and can be located only through gravity, we should consider Black Holes. Since every galaxy ever examined contains a Black Hole, it would be safe to surmise that dark galaxies contain them too. The dark halo surrounding a galaxy could contain billions of Black Holes. The "voids" in Space could hold billions of dark galaxies. The 71.62% of the Universe ascribed to "dark energy" could be hidden in these voids.
Atop Mauna Kea, the ultraviolet telescopes are grouped together in "Millimeter Valley." Using the UV spectrum, astronomers have discovered extremely bright young galaxies in the process of forming stars. 12 billion light-years away, we see them as they were when the Universe was less than 2 billion years old. They are the most luminous and massive galaxies ever seen at that distance.
The AzTEC submillimeter camera first detected a very bright ultraviolet source (left). Next the Smithsonian Submillimeter Array localised the source (centre). The Hubble Space Telescope database found this tiny point of light at the edge of detectability (right). This shows that the source is very bright but extremely distant, nearly hidden by dust. A bright ultraviolet signature indicates that the galaxies are in the midst of star formation, producing new suns at a rate 1000 times faster than our galaxy.
Astronomers have no idea how large galaxies could form so soon after the Big Bang. One way to form them would be around massive Primordial Black Holes. PBH's were formed from quantum fluctuations shortly after the Big Bang. Previously it was thought they would be tiny because of a finite speed of light. Discovery of massive dark galaxies is one more sign of a "c change" in physics.
This blog has always emphasised that there is more in the Universe than meets the eye. Theory predicts, and observations confirm that baryonic matter is only 4.507034% of the total mass. Flying over a city at night, the lights we see are just a hint of what lies beneath. The matter we see is only a small fraction of what is out there.
Object VIRGOH121 was first noticed in 2000 by its influence on a nearby galaxy. NGC 4254 has a huge stream of matter torn from its side. It must have suffered a collision with an object of 100 billion solar masses. When the most powerful telescopes looked in this region they saw nothing. VIRGOH121 contains no stars. Only by its radio emissions was it located.
When this research was first published, the astronomy community was very skeptical. Alternative theories were cooked up to explain the observations. Perhaps they invoked some sort of "dark energy." Now, 7 years after first publication, there is conclusive evidence that VIRGOH121 is a dark galaxy. It is entirely made up of dark mass, which could be Black Holes.
We are fortunate to have found VIRGOH121 because of its collision with a visible galaxy. There could be many, many more dark galaxies out there. If the dark mass is composed of Black Holes, they would have formed shortly after the Big Bang and never have been matter. Dark mass could be everywhere, even within our solar neighbourhood.
The next time you look up at the stars, try to imagine a parallel Universe occupting the same Space/Time. this Universe is hidden from our eyes, yet contains 20 times as much mass. Interactions with this dark mass created galaxies, stars and even planets. Our understanding of the Universe is just beginning.
Two discoveries announced in the past day, seemingly from different scales and regions of the Universe, may be related. The Hubble Space Telescope has found that Galaxy Cluster Cl 0024+17 is surrounded by a halo of dark mass. (This is distinct from "dark energy," which doesn't exist.) This cluster, 5 billion light-years away, apparently formed from a collision of two clusters about 1 billion years before this picture was taken or 6 billion years ago. The impact formed an expanding ring of dark mass which can be detected through gravitational lensing. Though mounting evidence exists, the nature of "dark matter" is still just a subject of speculation.
Just last week we learned of a hot gas giant orbiting inexplicably close to its star. Again using stellar occultation, astronomers have discovered that planet TrES-3 orbits its sun in only 31 hours! It's orbit takes the planet barely 3 million km from a sun. Current theories can not explain these hot Jupiters. In the immense heat near a star almost anything would boil away before forming a planet.
The Big Bang created billions of Black Holes in a variety of sizes. The biggest ones formed the seeds of galaxies and clusters. Smaller singularities formed great haloes around the galaxies, as seen near Cl 0024+17. Many times these objects have collided with a galaxy's disk. They could have formed the seeds of stars and even smaller objects like planets. Presence of a singularity inside "hot Jupiters" would explain their formation and number.
There is new evidence of disk of dark mass deep within our solar system, something I will write about sometime. There is far more out there than meets the eye.
Supernova 1987A imaged in X-rays by the XMM-Newton spacecraft. X-rays are produced when the expanding shock wave interacts with surrounding materiel. Astronomers have found many such bubbles around supernova remnants. Though supernovae are expected to have neutron stars at their centres, none has been found for 1987A. Some astronomers speculate that the core has collapsed completely into a Black Hole.
When all the galaxies, including "dark" mass, are weighed the total is only about 30% of the mass necessary to close the Universe. This has fueled more speculation about a "dark energy." Observations of clusters by Alain Blanchard's team indicate that dark matter is 4 times as prevalent as thought, comprise the 95% of mass that is not baryons. But where is it?
Radio astronomers have found entire dark galaxies in the vicinity of the Milky Way and Andromeda. These galaxies are composed entirely of "dark" mass. These have been found because they are relatively nearby. A dwarf spheroidal galaxy called Tucana exists far from any visible galaxy. No astronomer knows how many more dark galaxies are out there.
In this month's SCIENTIFIC AMERICAN astronomers Wallace Tucker, Harvey Tananbaum and Andrew Fabian write about immense Black Holes at the centres of galaxy clusters. These Black Holes create immense bubbles of high-energy particles, like a supernova but 100 million times more powerful! Tananbaum is director of the Chandra X-ray Centre and will be principal investigator of the CONSTELLATION-X spacecraft, assuming "dark energy" doesn't delay the project.
It is comforting to see similiar processes working at a variety of scales. Black Holes have a huge influence on structure, from stars to galaxy clusters. Could they get any bigger? Astronomers Margaret Geller, John Huchra and the Sloan Digital Sky Survey have shown that galaxies are arranged in enormous walls with bubble-shaped voids in between. These could be home to ultra-massive BIG GULP Black Holes. Early in the Universe's history they would have swallowed everything within reach, leaving behind great voids. The missing mass ascribed to "dark energy" could be hidden in those voids.
Big Gulp Black Holes would swallow any radiation and be nearly impossible to detect visually. They could be detected by their immense magnetic fields. Astronomers have found powerful magnetic fields of unknown origin in intergalactic Space. Those fields may be the sign of the Universe's missing mass.
Full-time scientist. Before graduating I learned that the speed of light is slowing down and originated the "GM=tc^3" theory, which explains the dark energy problem and most physicists still can't explain. More recent work seeks Black Holes in some unexpected places, even within Earth. I've been working at NASA in Houston on studies of the Moon, and have an insider's view of the Space program. Actress in film, television and stages from Honolulu to Houston. In spare time I fight off hostile aliens, explore a strange world and unusual forms of life.
