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Sukanya Chakrabarti / UC-Berkeley
The distribution of HI hydrogen in the Whirlpool Galaxy, as determined by the THINGS VLA survey, extends far beyond the visible stars in the galaxy and its satellite companion (marked by cross). Analysis of perturbations in the hydrogen distribution can be used to predict the location of such hard-to-spot satellite galaxies.
The search for Planet X may be problematic, but astronomers believe there's a "Galaxy X" lurking on the other side of the Milky Way.
Based on an analysis of our home galaxy's distribution of cold atomic hydrogen gas, two astronomers at the University of California at Berkeley are predicting that a previously undetected dwarf galaxy, about 1 percent the mass of the total Milky Way, should lie about 300,000 light-years out from the center of the Milky Way ... in an area that's obscured by intervening gas and dust.
Such a galaxy hasn't been detected directly — yet — but postdoctoral fellow Sukanya Chakrabarti and Leo Blitz are betting that it's out there nevertheless.
"This is the first time in my profession that I'm really going out on a limb and making a very specific prediction," Chakrabarti told me.
This month, a request is being put in for observing time on the infrared-sensitive Spitzer Space Telescope, as part of its GLIMPSE survey. If the request is approved, Chakrabarti and Blitz should find out sometime this year whether their bet has paid off. The payoff could be big: If Galaxy X is found, its existence could explain a curious discrepancy in the current theoretical model for dark matter distribution in the universe.
And if the bet goes bad? "Even if we're wrong, we'll learn something significant, because it could be due to the shape of the dark matter halo," she said.
Chakrabarti discussed her research, which has been submitted to the Astrophysical Journal, at the American Astronomical Society's winter meeting in Seattle today.
Reading the ripples
Our Milky Way is surrounded by about 80 known or suspected dwarf galaxies, known as satellite galaxies. Some of them are well-known in their own right, such as the Large and Small Magellanic Clouds. The problem is that there don't seem to be enough of them. The best model for dark matter distribution at large scales predicts that, at the scale of the Milky Way, there should be hundreds or perhaps even thousands of dwarf galaxies.
Chakrabarti and Blitz suggest that the "missing" dwarf galaxies may be so small and dim that they're obscured by the dust of the bigger galaxies in their neighborhood. The dwarfs may even be made primarily of invisible dark matter. But even then, they should create disturbances, or ripples, in the much larger pool of hydrogen gas within the disk of a galaxy. The gas is gravitationally bound to the galaxy, but extends much farther out than the galaxy's visible stars — sometimes as much as five times farther out.
That cold hydrogen gas can be mapped by radio telescopes.
"The method is like inferring the size and speed of a ship by looking at its wake," Blitz explained in a news release. "You see the waves from a lot of boats, but you have to be able to separate out the wake of a medium or small ship from that of an ocean liner."
To test the idea, the researchers looked at high-resolution radio data for the Whirlpool Galaxy and another galaxy known as NGC 1512, collected as part of the Very Large Array's THINGS and THINGS-SOUTH surveys. When Chakrabarti fed the data into her mathematical model, the results accurately predicted the locations of two known satellite galaxies. The Whirlpool satellite was a third the mass of the primary galaxy, while the NGC 1512 satellite was one-hundredth the mass of the big galaxy.
Chakrabarti said her model should work with galaxies as small as a thousandth of the primary galaxy's mass.
When she and Blitz checked radio data for the Milky Way, the model pointed to a dwarf satellite galaxy that's around 3 billion to 10 billion solar masses, or roughly one-hundredth the mass of the Milky Way. The galaxy should be on the opposite side of the Milky Way, somewhere in the constellations of Norma or Circinus, just west of the galactic center in Sagittarius when viewed from Earth.
NASA's Spitzer Space Telescope would be well-suited for spotting such a galaxy, because its infrared camera can see objects that are obscured by dust in visible-light wavelengths. While Chakrabarti and Blitz wait to find out whether Spitzer will be able to look for Galaxy X, they're also checking dozens of other galaxies to make sure their mathematical model holds up.
Planet X vs. Galaxy X
Chakrabarti likes to compare her quest to the search for unseen planets in the 19th century. Most famously, the French mathematician Urbain Le Verrier predicted the position of a new planet in 1846 purely by analyzing its gravitational effect on other celestial bodies. When the German astronomer Johann Gottfried Galle looked where Le Verrier predicted, he found the planet Neptune almost immediately.
That success sparked a search for a supposed planet within the orbit of Mercury, called Vulcan. (It turned out, however, that Mercury's perturbations were explained instead as a consequence of Albert Einstein's general relativity theory.) The discovery of Neptune also led Percival Lowell to start searching for a planet even farther out, which he called "Planet X." That quest eventually resulted in the discovery of Pluto in 1930. (You can read all about the quest for Planet X in my book, "The Case for Pluto.")
Some observers suggest that there could be yet another Planet X still out there — perhaps a giant planet on the far edge of the solar system. And some have even claimed that an as-yet-undetected planet is heading our way for a close encounter in (gasp!) 2012. There's no chance of that happening, but NASA's Wide-field Infrared Survey Explorer, or WISE, would be capable of seeing a distant Planet X if it's the size of Jupiter or bigger.
The WISE mission's principal investigator, Edward Wright of the University of California at Los Angeles, told me that such a Planet X would be detected as a brown dwarf candidate, moving across the background of stars. More than 1,000 brown dwarf candidates are being checked right now, and if any of them "are moving a lot, then you'll hear from us," Wright said.
Chakrabarti marveled at the difference between the 19th-century search for Planet X and the 21st-century search for Galaxy X.
"In the 1800s, all Le Verrier had was one solar system," she said, "whereas we can now go and test the statistical viability of this method on a very large sample of galaxies."
More about dark matter and Planet X:
- The darkest mystery of them all
- Gallery: Dark matter revealed!
- New dark matter map created for big galaxies
- Large 'Planet X' may lurk beyond Pluto
Connect with the Cosmic Log community by "liking" our Facebook page, or by following msnbc.com's science editor, Alan Boyle, on Twitter (@boyle).
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I think Chakrabarti has a little bit more evidence towards a galaxy X than just about any planet X proponent. However on that note, it would be very interesting if we were to find a 9th large orbiting body within our solar system, because of the long odds for the exsistence of such a body.
It depends on what you consider a "large" orbiting body. Sedna was discovered in 2003 and Eris was discovered in 2005 (larger than Pluto). If the question is: "Are there more Pluto-sized objects in our solar system that are yet to be found?" The answer is almost certainly "yes"--several of them are yet to be found.
The Kuiper Belt flourishes with objects between 30-48 AU, then suddenly terminates at ~48 AU. This is known as the Kuiper Cliff. Some hypothesize that this "cliff" could be attributed to the presence of an object with a mass between that of Mars and Earth located beyond 48 AU. Astronomers have not excluded the possibility of a more massive Earth-like planetoid located further than 100 AU with an eccentric, inclined orbit. There are also many computer simulations that support the existance of an Earth-sized objects existing in an eccentric orbit between ~100-200 AU.
In 2007, Mike Brown (the discoverer of Sedna and the enemy of "planet" Pluto) said: "Sedna is about three-quarters the size of Pluto. If there are sixty objects three-quarters the size of Pluto [out there] then there are probably forty objects the size of Pluto ... If there are forty objects the size of Pluto, then there are probably ten that are twice the size of Pluto. There are probably three or four that are three times the size of Pluto, and the biggest of these objects ... is probably the size of Mars or the size of the Earth."
Personally, the most exciting topic in astronomy is exoplanet research, but discovering "what else is out there in our solar system" is a close second.
O.k. I will clarify, and object that would qualify as a full sized planet. I will admit that I have not kept up to date on this information however, because of the exoplanet hunt, which yes, is extremely exciting, especially since there is a grown case for Earth-like planets
There are indeed several named Kuiper belt objects including Sedna and Quaoar which are apparently somewhat larger than Pluto and have enough gravity to be basically spherical in shape.
I don't know what the origin of the myth about a giant brown dwarf orbiting in binary with the sun on an earth crossing orbit which will destroy us on 2012 is. Obviously ridiculous.
(Having nothing to do with 2012)
There are hypotheses that suggest there's a dim red dwarf or brown dwarf that resides in our Oort cloud (known as "Nemesis"). Also, WISE has recently discovered two previously-unknown red dwarfs that are in our neighborhood (distances from Earth are TBD).
Hey I remember the "Nemesis" myth. And no, it wasn't connected to 2012, I remember reading that it was supposedly linked to most of the mass extinctions that have occured on this planet. Correct me if I am wrong though, wasn't there once evidence showing that Neptunes orbit was being affected by another body further outside of Neptune's orbit? Its been a really long time since I looked up anything related to that.
Why am I reminded of that tune from the 80's:
"Big black Nemesis, parthenogenesis
Everybody happy as the dead come home..."
It's kind of a corny goth-pop tune, but ya gotta love that initial rhyme!
Seriously, I have no idea where the "Nemesis myth" came from, I just know that Isaac Asimov wrote a novel in 1989 which contained a red dwarf star, that the characters decided to name Nemesis, that was obscured from Earth observation by a dust cloud, and was expected to swing by close enough to destabilize Earth's orbit, dooming Humanity. I imagine that this book got conflated with the pre-existing theories about Nemesis and gave rise to the Nemesis BS you can read on the Internet today.
man, that IS ridiculous! it's GOT to be no earlier than 2013!!! LOL
Alan, why is the last sentence even necessary? What does it even mean? What would a dwarf galaxy made up of dark matter actually be? Billions of "Dark Stars" orbiting around a Bright Hole? Sounds like something the Grateful Dead or Crosby, Stills & Nash might write songs about.
Actually, they're almost certainly composed mainly of dark matter, as all of the galaxies in our solar system are. Dark matter dominates over visible matter. It probably consists of exotic particles, but folks don't exactly know what it is yet. That's why it's called dark. I might tweak that sentence slightly so that it doesn't sound like such a big deal that dark matter dominates. And here's a link to a story and interactive that provides further explanation:
http://www.msnbc.msn.com/id/3077833/ns/technology_and_science-space/
We have galaxies in our solar system? They would have to be really "dwarf" galaxies.
Sorry, but I couldn't pass that one up.
So wait... are they Dwarf galaxies because they have not cleared their orbits?
That's a handy summary, Alan, but nothing new to me. I'm not an expert astrophysicist but I've been following this stuff, mostly out of curiosity, for some time.
I'm familiar with the observations of the spin rates of these galaxies which leads to the supposition of something more there to hold them together, I'm just willing to accept that this "something more" needs to be a new mysterious unknown kind of stuff which we are unable to detect anywhere around us.
So, what are the possibilities: MACHOS? Black holes, brown dwarfs, neutrons stars and such? Perhaps. Especially considering that the estimated mass of the black hole at the center of M87 was just increased to almost 7 Billion solar masses. That's a possibility.
WIMPS? Here's where I have to pause. Admittedly, I'm not an expert cosmologist, but the idea that there are enough of some sort of mystical particles, neutralinos (Whaaat?), or some other whacky made up nonsense which actually composes 80 to 90 % of the mass of the entire universe, but for some reason, we can't even detect them, is, I'm sorry to say... bunk. It makes so sense whatsoever. Perhaps I'm naive, and unqualified to do so, when experts like you who know way more about this stuff than I do are willing to entertain such notions, but I reject that hypothesis. You might as well say that god makes the galaxies spin the way they do and be done with it.
A third possibility exists: Diffuse gases and spacedust. These materials would not emit light so they would not contribute to the brightness factor on which the total mass of these galaxies is estimated. In this very article the scientists discuss how the halo of elemental hydrogen extends 5 times further beyond the visual edge of the galaxy. Since the stars within the galaxies are constantly forming and exploding in an endless process, their constituent materials, including heavier elements than hydrogen, in fact all of them (if I correctly understand how the heavier elements have been formed over time by fusion processes within massive stars), must be spread out diffusely within interstellar space. How come there's never any mention of this? Could this be the "missing mass"?
Is any option is left? Perhaps there is an error of some sort in the observations, calibration of those observations, calculations based on miscalibrated observation, and assumptions and suppositions which are then made to account for and explain these bad calculations. For more on this, check out this link:
http://ww.space.com/8588-dark-energy-dark-matter-exist-scientists-allege.html
Comments?
MM
About your third point; Dust and gasses ARE detectable, by their absorption of light passing through them.
Darth, OK. Absorption spectra, good point, how come this is never mentioned? If the mass of mysterious "neutralinos" can be posited as the missing stuff, what about the gas and dust?
MM, Because they haven't seen enough light absorbed to account for the mass needed to cause the gravitational effects observed.
But are they so sure about the amount of "regular" mass? I hate to sound like I'm beating a dead horse, but I'm much more prepared to believe that various measurements and calibrations of those measurements are off, than I am to believe that there is some kind of stuff out there which makes up 4 to 5 times more mass than the kinds of stuff we're already familiar with.
If this "dark matter" stuff really exists, it should be detectable nearby as well, and as for neutrinos, which may or may not even have any mass at all, well IMHO, that just ain't gonna cut it.
MM They keep trying to find enough 'regular' matter, but can't seem to do it. I agree with you that 'dark matter', being some kind of unknown substance/state of energy, (Energy = matter = mass), that we can't detect, seems like grasping at straws.
On the other hand, look how long it took us to discover neutrinos. It seems a safe bet there are more surprises "out there".
Perhaps entire galaxies composed of dark matter with dark matter suns?
Its not galaxies we are looking for. We can't find enough matter in our own Galaxy to account for it's collective gravitational field.
The benefit of detecting an object of this magnitude would be a better understanding of the local mass of the Milky Way area. The more accurately we can detect all the local objects in the gravitational field, the better we can calculate the effects of that gravity on more distant objects.
This, in turn, would reduce the uncertainty in estimating the distances to the local group galaxies, and bring more detail into focus as our estimates become proven factors.
This is why science is so superior to any other method of understanding our universe: it constantly refines its estimates and calibrates details to improve our understanding of our universe. This is why science will always seek the truth where blind belief systems will stubbornly cling to untruth in loyalty to mythological teachings.
No.
The problem with holding an appreciation of science and "blind belief systems" as you call them is that most scientists have a Sunday-School level theological education and most people of faith have at best a high-school level science education. They are not mutually exclusive and they both seek to understand truth. Theology is constantly in a state of change to adapt ways of understanding spirituality with modernity.
I have found at least equally rigorous defense of long standing scientific beliefs as theological ones in the face of contrasting evidence. A cursory look at scientific history reveals that case over and over again.
Science is as much a faith based endeavor as religion. The real difference is the scientist requires numbers to support his belief and the religious do not. That does not mean that neither challenges and adapts their belief system.
Very true! Catholics no longer burn people for being heretics. Very good improvement. Most Mormons gave up multiple wives though... not sure if that was an improvement or not...
Ever seen a quark, dark matter, or a photon? You have mathematical constructs that tell you they are there or have seen the result of them acting on another system to tell you they are there, but you at the end of the day, are taking it on belief that it they are there because you can't see or touch them. Einstein won a Nobel for the photoelectric effect I think -- he never saw a photon or even believed they existed. But his experiments and equations indicated that light was packaged up in discreet particles. Everyone else believed that light was a wave that could "magically" move through a vacuum, or that there was a special aether that existed for light to travel through -- Michelson and Morley still have a nice little mock-up of the failed experiment to find that aether at CWRU.
You can be snarky I suppose, but theology touches on the human condition in the same way that science does on the natural world. People have an innate need to understand their place in the world and Gods and Scientific study are born. Gods come and go and have evolved over the centuries to reflect a more grounded (most of the time) human race. Catholics don't burn people at the stake anymore but there was a time that people believed that was just as right to do as scientists who were convinced of the existence of an luminiferous aether -- eventually they both find a better a truth to subscribe to.
Spiritual belief has led many people to lead a more self-reflective life. Scientific belief has led many people to believe they are superior to them because what they believe has numbers associated with it. It is sad.
Isn't Galaxy X where the "Shaving Cream Molecule" is found?
The Universe fascinates me to no end. Pun intended.
Oh I am sure the universe has an end. Its just the distances within the universe are larger than what the human mind can currently comprehend full, and the speeds required to reach that end are probably unattainable.
Yes it is a very fascinating and interesting place we live in.
at one percent the mass of the milky way, I bet there are more than one, perhaps smaller.....good inductive reasoning on her part and nice to have an astronomical target worth "looking" for. Why does she put it on the opposite side? to balance out the drawf galaxies on this side?
The following are things which I have been saying for years now. I personally believe that quantum free space makes up much of the missing mass of our Universe, and that the evidence of what they are observing with the "Dark Matter" distribution inside of these galaxies is mostly due to varying densities of quantum free space. I have also said that I tend to believe that matter is composed of both quantum bound energy and quantum bound space, and that when matter is converted to quantum free energy, matter is also converted to quantum free space, and it is this conversion process which is responsible for the spatial inflation of our Universe. I also said that I believe that the supposed evidence for "Dark Energy" is actually our old familiar force known as gravity, as the inertial expansion of our Universe overtakes the spatial expansion of our Universe, and the curvature of space at the outer fringes of our expanding (closed system, finite) Universe turns this matter back in, so that it is once again accelerating back together again under the force of gravity. I have also said I tend to believe our Universe is actually a contiguum which is actually dimensionally dependent on a greater outside continuum, for which I accept the term "hyperspace". I also said I hope one day we will be able to go up into hyperspace as a fast way of getting around our closed system, finite Universe, the way that we can now go up into outerspace as a fast way of getting around our closed system finite world. IMO, there actually was no free space in our Universe to begin with, it was all created out of the Universal Superparticle which exploded in the "Big Bang". I have also said I tend to believe that it was a collossal matter/antimatter reaction which drove the "Big Bang", due to a partial or incomplete inversion of the Universal Superparticle. Doesn't anyone out there remotely agree with me, or are they afraid to say anything about these theories because I have also repeatedly warned everyone about these deadly ET installed terminal religious "End Time" belief systems which are threatening to crash and explode our emerging human world in a final programmed cataclysm of global warfare fueled with WMDs, known as the Christian Apocalypse or World War III, and eventually lead to the completely extinction of all mankind here on planet Earth at the hands of outside offensive totalitarian ETs ??? Oh, well, you really can't say I didn't try very hard to enlighten all of mankind. - RC
One thing is for sure RC, you drive home the point of "I have also said..." repeatedly. It would seem your as self absorbed as a black hole. Having said that, I have also just said I don't agree to disagree or agree with anything you said or not.
RC, way to hang it all out there! Gotta like that. But why limit the diabolical ET plan to installing only toxic religious belief systems? It's just as likely that they have sent agents provocateurs, like for example Newton and/or Einstein, to confuse our scientific beliefs as well. This would guarantee we would be woefully unprepared for a final showdown. Personally, I believe we have met the Alien, and it is us.
(I know, I know, I am going to get deleted again. What can I say in response to all of this, except bye, bye!) - RC
I don't care what the revisionists, (probably a bunch of creationists), say; Pluto IS a planet. It has an atmosphere and a Moon, and that's good enough for me. Besides, Mr. Johnson, my science teacher in 7th grade told me it was, and that's that!
In other words, to explain all this in laymen terms, a black hole acts like a super humongus vaccumn cleaner, sucking up everything within the range of its gravitational field. Being so huge, dense and powerful- everything it consumes is compressed into such a tight space that not even light can escape. At least until it becomes so obese that at some point over eons of time it finally explodes a massive belch of regurgitated puke waste into a cosmic version of yes- you guessed it, 'The Big Bang'!!!!! And maybe that's why we're all such a big mess today... time to regurgitate.
Supermassive black holes have the density of water? Who would've thought. I didn't believe it at first, but I just did a bunch of math which I won't bore you with, but if I got all my powers of ten correct and conversion from Km to cm for comparison to 1.0 g/cm^3 (the density of water), dang if I didn't come up with about .015 g/cm^3, which is about a hundredth of the density of water. Something doesn't seem right about this.
I'd say this story needs to be rated X. I put my x-ray glasses on to read it and seen right thru it....yep
Whoosh! It went right over my head. My tiny monkey brain cannot even begin to comprehend this.
But it's interesting and I appreciate the information. I'm glad the folks with those great big giant monkey brains are working on it.
Ok, back to trying to color inside the lines.
I must admit I am a junkie for this stuff even though my ability to comprehend the math and formulas stopped evolving about thirty years ago-- but I can get the theory and concept pretty much. If I can handle advanced theology and philosophy this is a piece of cake. What fascinates me is the sheer newness of it and the constant thrill of discovey and of course the imaging "What would a world around a "Nemesis" be like and of course, what are the impliacations and possibly utility of it for man.
I view both the creationists and religion haters who latch on to these things and use them as a club as simply distracting and unproductive nuisances that obscure the real importance of this. While I am a conservative, believing Christian, I am not a fundamentalist and believe evolution and the Big Bang are perfectly compatable with scripture and fall within the "In the beginning God created the Heaven and the Earth." He is free to use whatever methodolgy he wished and big-bang and evolution are mrely one tool among many he could have used. So yes, I am quite willing to accept these discoveries of science and marvel at them-- and move on. Scripture, and religion is not about science or the physical world, it is how God (or "the Gods") wish us to act and treat each other and what is the "good, the true and the beautiful." For my own particular faith, Christianity, God cares far more how you live your life and treat your fellow man than if you believe he did it in six days or billions and billions of years.
OK Having dispensed of that part, we can get back to the objects (we hope) at hand. Obviously what is alluring about the possibilities of "near earths" in mass and size are that we might some day be able to go there and colonize them. Even though they might be frozen dark worlds way out in the Oort cloud does not preclude they are useless. The earth derives virtually all of its energy from the Sun and has an atmosphere and life etc., all dependent in some ways on the existance of the sun in close proximity. But energy is energy and outer space posess' energy in abundence. Even a red or brown dwarf produces energy and the necessities of life (water, oxeygen, nitrogen) whizz by in enormous quantities. Any planet the size of earth might very well have molten cores which are going to provide enormous energy on its own, and even a brown dwarf can help. Granted, we may NEVER be able to walk on the surface of such a world unaided, but the presence of energy (geo-thermal) or derived from massive nuclear power generators could power lights and heating sources such to make vast gardens and open spaces.
No, I have not given up my "Buck Rogers" dreams of childhood simply because many of them have come true. Why can't they all.
When we start postulating dark matter, I just keep thinking of astronomy, pre-Kepler and Copernicus. With the earth as center of all, scientists kept coming up with more and more convoluted theories and mathematical expressions to account for the motion of planets. Kepler and Copernicus were the morons of the class - just couldn't keep track of the math, so they came up with a simpler explanation. Once you took the earth from the center, the math got a lot simpler with the planets circling the sun. Now, we are coming up with more and more elaborate systems to account for the missing mass - we need another Copernicus and Kepler, to come up with a simpler theory.
While not specifically related to this article, I do have a question that I've always pondered - With science and physics showing that the universe is constantly expanding, and the edge being nearly 13 billion light years away, I've always wondered about what is on the other side of the universe. What are we expanding in to?
other universes
JR- Chris is right, plus we don't know how much is out there that is just too far away for the light to have yet reached us. For all we know, 97% of the universe could just be too far away to be seen.
If there is another galaxy behind the Galaxy, we should also check if there is another sun behind the Sun. Or maybe there is another moon behing the Moon.
Maybe it's just me, but that makes no sense.
Now how did I just know that someone would turn this into a Mothra (religion) vs. Godzilla (science) debate?
I know it spoils the plot, but Godzilla ALWAYS wins!
Gamera was the best...
Never really thought about it like that before. Wow.