‘Green Peas’ Offer Tiny Clues to Early Universe

Article written: 5 Apr , 2013
Updated: 23 Dec , 2015

Today, we see an unobstructed view of the cosmos in all directions. But, a time existed near the Big Bang when the space between galaxies was an opaque fog where nothing could be seen. And according to two University of Michigan researchers, rare Green Pea galaxies, discovered in 2007, could offer clues into a pivotal step, called reionization, in the Universe’s evolution when space became transparent.

Reionization occurred just a few million years after the Big Bang. During this time, the first stars were beginning to blaze forth and galaxies. Astronomers believe these massive stars blasted the early universe with high-energy ultraviolet light. The UV light interacted with the neutral hydrogen gas it met, scraping off electrons and leaving behind a plasma of negatively charged electrons and positively charged hydrogen ions.

“We think this is what happened but when we looked at galaxies nearby, the high-energy radiation doesn’t appear to make it out. There’s been a push to find some galaxies that show signs of radiation escaping,” Anne Jaskot, a doctoral student in astronomy, says in a press release.

In findings released in the current edition of the Astrophysical Journal, Jaskot and Sally Oey, an associate professor of astronomy, the astronomers focused on six of the most intensely star-forming Green Pea galaxies between one billion and five billion light-years from Earth. The galaxies are compact and closely resemble early galaxies. The objects are thought to be a type of Luminous Blue Compact Galaxy, a type of starburst galaxy where stars are forming at prodigious rates. They were discovered in 2007 by volunteers with the citizen science project Galaxy Zoo. Named “peas” because of their fuzzy green appearance, the galaxies are very small. Scientists estimate that they are no larger than about 16,000 light-years across making them about the size of the Large Magellanic Cloud, a irregular galaxy near our Milky Way Galaxy.

Using data from the Sloan Digital Sky Survey, Jaskot and Oey studied the emission lines from the galaxies to determine how much light was absorbed. Emission lines tell astronomers not only what elements are present in the stars but also much about the intervening space. By studying this interaction, the researchers determined that the galaxies produced more radiation than observed, meaning some must have escaped.

“An analogy might be if you have a tablecloth and you spill something on it. If you see the cloth has been stained all the way to the edges, there’s a good chance it also spilled onto the floor,” Jaskot said. “We’re looking at the gas like the tablecloth and seeing how much light it has absorbed. It has absorbed a lot of light. We’re seeing that the galaxy is saturated with it and there’s probably some extra that spilled off the edges.”

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44 Responses

  1. lcrowell says

    At one and five billion light years distance these objects are situation long after the reionization phase

    • The Latinist says

      I think the point is that this is evidence that at least one type of galaxy exists that emits ionizing radiation. Since we previously knew of none but knew that reionization had occurred, this is a sort of proof if concept.

  2. What are the chances that the universe is really infinite with no big bang? Our telescopes are not strong enough to see far enough.

    • The Latinist says

      Not sure what this has to do with the article, but I’ll bite. If you wish to propose that there was no Big Bang, you will need to provide a theory that explains the 90+ years of observations telling us that everything in the universe is moving away from everything else in such a way that approximately 13.82 billion years ago all of space occupied a single point. What is your theory?

      • Me says

        The thought gave me a scare! I bit lightly. I.let go really quickly. The thought gave me the chills too.Take care.

      • Torbjörn Larsson says

        Nitpick: The 13.82 billion figure is from a confusing press conference, it is the age derivable from Planck alone. If we want to use the consolidated data set (say, to compare with WMAPs latest such of 13.77 billion years) from the papers, the best Planck estimate of universe age is 13.80 billion years.

        But, he asks, what is 20 million years between friends?

      • The Latinist says

        Thank you for the correction. I have to admit that the article I read on the subject was rather confused, and I have not had the time to review the papers myself.

      • ‘Tired’ light. I kow that there are reasons to dispute this… but the reaasons are fluctuating left and right.

    • Me says

      Wow what a thought.

    • Olaf2 says

      Strong enough to see at least 13.82 billion years away.

      • Torbjörn Larsson says

        Well, within bounds it is possible we can see that far away. But not as likely, the best age estimate is 13.80 billion years, see the Planck papers.

    • Torbjörn Larsson says

      What are the chances that the universe is really infinite with no big bang?

      The likelihood that the universe is infinite is good, it is a simple theory and perfectly consistent with the flat space measured.

      The likelihood that there is no big bang is too small to bother with. Planck measured some big bang features to 25 sigma, which means that the likelihood that it is mistaken (random variation in the data) is something on the order of < 10^-20.

      But, here is where alternative theories run into trouble, from the first Planck result conference:

      Go down to the 3d figure in the above link, showing the CMB temperature spectra as measured by Planck. It shows a power spectra vs feature size. (Imagine putting differently sized circles on the sky and measuring the CMB power beneath.)

      Note how well the standard cosmology predicts (red line) the data (blue dots). To the right of the dotted line the fit is perfect because there is no problem with cosmic variance (too large features to get good statistics). To the right we can see that our universe is still not too odd, ~ 1 in 100 universes will look as ours.

      This is a fit curve, i.e. the Planck team has gone through millions, sometimes 100s of millions, parameter combinations of the 5+1 parameter standard cosmology until they found the best fit.

      But now go up to the 2nd figure, showing the first detailed polarization data out of Planck. (Imagine drawing vectors from colder spots to hotter spots.) Note how fantastically well the red lines covers the blue dots in both data graphs.

      This is not a fit curve! It is the only prediction you can make from establishing the earlier fit! As the text notes

      “Still, at the small angular scales, the polarisation data can be trusted and in this data Planck have one of their most impressive figures. The figure below shows how both the temperature multiplied by the polarisation (pixel by pixel on the sky) and how the polarisation itself varies with angular scale. The blue dots are the measured signal. Now, the red curve is not the best fit curve to this data. That is worth pausing and reflecting on. If it isn’t the best fit curve, then what is it?

      That curve is the unique prediction from analysing Planck’s temperature data. There are no free parameters in defining those red lines. Once the temperature data is analysed, we can make an unchangeable prediction for what the polarisation should look like. The fact that the red line goes straight through the blue data points is absolutely remarkable. However, if one believes in the big bang and standard cosmological model, this is all that could have happened. If one doesn’t believe in the big bang, then not only is there no reason to suspect that the CMB exists, or that it is polarised, but certainly not that the way the polarisation averages on particular angular scales should look like that.

      I think it is worth pausing for one second longer on this. I’m about to start describing a few “features” and anomalies that might be present in the Planck data. It is tempting for a person cynical about natural science to pick up on these anomalies and say “scientists don’t understand what they’re doing, look at all these anomalies”. The thing is, scientists are trying to understand everything. It isn’t enough that the model explains almost everything, every possible failure is looked for and analysed. If someone wants to replace the big bang, or any other aspect of cosmology (or well-established science) it isn’t enough just to explain how to create these anomalies. Any alternative model must also reproduce everything that works. Without the big bang the prediction for that red line would be a horizontal line through zero. That wouldn’t be called an anomaly, that would be called a completely failed model.”

      [Text cursive removed; my bold added.]

      The figure text pounds on this some more:

      “These curves reflect some of the best of humanity. These are the tiny fluctuations in the polarisation of a field of radiation, left over from a hydrogen plasma that permeated the entire universe, 14 billion years ago. The oscillations in the curves come from sound waves in this hydrogen plasma. The curve is our prediction for this data, with no free parameters to play with at all. Just reflect on that. I’m unable to describe how incredible this is. We don’t even know whether Shakespeare wrote Shakespeare’s plays, but we can predict exactly what the polarisation in the CMB should look like.”

      [My bold.]

      So there you have it. Any alternate model is by its very nature (no big bang, so no CMB polarization prediction) “a completely failed model”.

      Our telescopes are not strong enough to see far enough.

      That is not what happen though. The CMB comes from a few 100s of 1000s of years after inflation stopped, when the universe was cold enough to form atoms and let the light travel unhindered.

      That puts up a wall beyond which our EM observatories can’t see. If we want to look farther, we need to use neutrinos that wasn’t hitting free electrons (much) as the early light. And AFAIK people have started to look with neutrino observatories.

      But, the point is that we see much as far as we can, due to the finite age of the universe, not the distances involved. Older light wouldn’t have time to travel to us, which goes into the concept of the observable universe.

      • GregtheThird says

        One of the oddities about inflation is that it likely pushed parts of the universe beyond our ability to observe it. And we don’t know how much of it this applies to. The 13.7 billion years of space we can observe is now due to expansion 47 billion light years apart. Some estimates that inflation created a universe a million times bigger. Others speculate that inflation is ongoing even now at the edges of the universe.

      • Torbjörn Larsson says

        It is unfortunate that inflation doesn’t solve the problem of knowing the topology of the universe, but at least it gives a natural suggestion (flat space).

        AFAIK we can see from cosmic variance (the observed homogenity at large scales) that the universe extends at least 10 times what we can see in every direction, so at least 1000 times as large as the observable universe. (Jumping over some details on the difference between what we can see now and the OU.)

        Ongoing inflation is eternal, and that is another basket altogether. I don’t think Planck helped those who are looking at early bubble universe collisions much. The anomalies didn’t move from being low confidence.

        We may see the EI multiverse in our accelerators, but likely not from the sky.

    • Patreon
      Aqua4U says

      Careful… you might step on someone’s ‘religious faith’ here? The denizens of the ‘Big Bang’ theory are numerous and wildly vociferous in their united opinion on this subject. It is far too EASY to degrade into a shouting match with the disciples of this faith! They have SO much data (Confirmation bias) to back them up, how could you possibly doubt them? Oh ye ‘Heretic’ of little faith!

      It’s interesting to note the first words in the Judeo-Christian bible… “In the beginning…” This implies there WAS a beginning, HAD to be and furthermore it insinuates an end? A basic tenet of the ‘Big Bang’ theory and a most curious corollary.

      Foremost among the basic tenets of the ‘Big Bang’ theory is the ‘red shift’ theory. Proven by our sciences to be an effective intergalactic yard stick, ‘red shift’ outlines the very dimensions of our universe! (Keep your fingers OFF THE EQUIPMENT!) But, COULD it still be possible the calculations are off a tad? A very small or miniscule change in the numbers would be a real ‘game changer’! Are there unforeseen forces at play? Probably YES! Ask the ‘fat lady’ if she’ll sing for us?

      • The Latinist says

        I am not at all sure what you’re trying to imply. Are you suggesting that redshift is not a real phenomenon but has been invented by astronomers? If so, do you have any evidence to support the claim? You could measure it yourself for some objects without too much equipment; have you tried? Or are you suggesting that scientists are manipulating the redshift measurements from which they determine radial velocities of cosmic objects? If so, do you have any evidence to support this claim? Or are you perhaps suggesting that redshift, while real, does not represent a shift in the spectrum due to radial velocity? And, if so, what is your alternative theory for the cause of the observed redshift?

      • Patreon
        Aqua4U says

        Red shift exists alright, but the question remains: Have we accurately accounted for all possible variables, including time dilation, gravitational and electro dynamic forces?

      • The Latinist says

        Do you have any evidence that gravitational redshift can account for the observed relationship between distance an redshift? Do you propose that more distant galaxies are systematically more massive than nearer ones, or are you positing some other sort of gravitational time dilation? I’m not sure what you mean by “electro dynamic forces” — what mechanism are you referring to? And do these gravitational and electro dynamic mechanisms you are describing better explain the data we have or make predictions that differ frim those of hubble-law expansion that we could test?

      • GregtheThird says

        By gravitational anomaly, are you referring to the “axis of evil” problem?

      • Me says

        lol…that was a good one.

      • GregtheThird says

        I was hoping to get into a conversation on the topic as it applies to the latest Planck data, but that conversation will have to wait for another time.

      • Patreon
        Aqua4U says

        Should be… unaccounted for gravitational anomalies… at quantum scales?

      • The Latinist says

        Again, do you have any evidence that such things exist?

      • Patreon
        Aqua4U says

        it’s in my nature I guess? Am ambidextrous with the left side/right brain dominant. Neither of my parents were left handed. I play the fiddle, guitar and baseball right handed… ping pong with either hand, then eat and write left handed. Bottom line is that I’m not your typical left handed hitter…

        I really like what Leonard Shlain wrote:

        “We can see that the right hemisphere processes information as an all-at-once holistic gestalt by using multiple incoming, converging determinants and integrating them synthetically. Simultaneously, the opposite of sequential time, is unique to the right brain which functions best in a visio-spatial context, correlating parts to a whole while intuiting diverse relationships among them. Since multiple determinants, multiple emotions, multiple meanings, multiple images, and multiple sounds converging in one state are expressed most easily through the metaphor of space, the right side is the better side for appreciating dimensions and judging distances… In contrast, the newer, left cerebral hemisphere controls the dominant right hand and is concerned with doing rather than being. Since the act of willing most often originates from the left brain, the right hand usually picks the berries, throws spears, and fashions tools. Instead of simultaneity, the quality that makes us Homo faber, the toolmaker, depends on a sequence of steps that exist in time.”

        “The heart has reasons that reason will never know.” – Blaise Pascal

      • The Latinist says

        Sorry, but that is not science. I hope you have not considered this exchange to be a “shouting match,” as I have tried to remain respectful in all my replies, but I am afraid I have to stop here. Your comments appear to be based on nothing more than intuition and insinuations about the motivations of scientists and therefore have no basis in fact. I’ve asked you several times for evidence, and all you’ve offered is pointers to irrelevant articles and some new-age mumbo-jumbo. I don’t really have any interest in your speculation; all I care about is the evidence. Since you seem to be unable to offer any evidence that would suggest that expansion is not the best explanation for Hubble Law redshifts (or indeed any alternative theory at all), I will, respectfully, bow out of this conversation.

        And no, this does not make me closed-minded or make my acceptance of cosmic expansion “faith.” I would be glad to learn some new theory that better accounts for our observations. Nothing would be more interesting to me. But it must be based in evidence, not wishful thinking.

      • Patreon
        Aqua4U says

        Some people don’t see patterns in things….

      • The Latinist says

        Some people recognize that human pattern recognition abilities, while amazing and useful, often see patterns where none exist; and these people have developed a means of testing the patterns they perceive through the application of a standard methodology and an unbending requirement for evidence to support their ideas. Such people are called scientists.

      • Patreon
        Aqua4U says

        And yet it took a couple of bicycle mechanics to get us flying…

      • The Latinist says

        The Wright Brothers were great experimentalists. They didn’t build the airplane according to any preconceived notions or ideas of how it “should” look; they tested wing designs in wind tunnels, measured the lifts of various designs, and settled on designs based on the evidence. They were, in other words, scientists.

      • Patreon
        Aqua4U says

        ‘Spooky action at a distance’ sound familiar? It’s called quantum entanglement. There is supposedly an experiment going up to the ISS… as proposed by the Institute of Physics and German Physical Society’s New Journal of Physics to test this more fully. I hope it flies!

      • The Latinist says

        What does quantum entanglement have to do with anything? Entanglement is an experimentally verified phenomenon which has been observed countless times. It’s definitely not fully understood, but that doesn’t mean it creates a license to speculate wildly about unrelated phenomena. What are you trying to suggest, that quantum entanglement is causing cosmic redshift? If so, I don’t think you understand even the basics if quantum mechanics.

      • Patreon

        @Aqua4U That certainly strikes a chord. It does sound so much like a repetition of Genesis but illustrated with superficial scientific embellishments. Even though one day Big Bang theory might be well proved to be true, even if that in itself is done so partially, it is good to remind ourselves that it is still theory and not yet factually verified. The periodic table of elements had indeed been objectively factually verified by experiment though not the Big Bang theory, I think. I don’t deny an expanding and accelerating universe but only about a century ago people were convinced that the Universe was comprised of just the Milky Way Galaxy. Could the Universe be much bigger? For example, relatively recently, the largest structure ever discovered in the universe is around 4 billion light years wide (See link below). What if what we can register of the Big Bang nowadays is just a signature of something vaster within which it is still happening? Perhaps what we are registering of the Big Bang is just a trajectory of an event inside something else.


      • Torbjörn Larsson says

        Even though one day Big Bang theory might be well proved to be true,

        It is the observed fact, do keep up with Planck et cetera.

        We also know that “no big bang” alternatives are completely failed models.

      • Patreon

        @ Torbjörn Larsson You sound so adamantly like a creationist yourself, with all due respect

      • DarkGnat says

        I don’t see anything unusual. Every story has a beginning, and as long as time exists, there will be beginning and endings.

        To compare science to religious/mythological texts seems a bit pointless. The creation story in Genesis is there to “set the stage” and wasn’t necessarily meant to be taken literally. It was simply a very poetic way of saying the God created everything.

        God is not a testable concept. We can’t confirm or deny the existence of something that can’t be observed or measured, which is rather like many multi-verse ideas, in my opinion.

        We can only go with what we have, and the “big bang” seems to make the most sense.

      • Torbjörn Larsson says

        Creationists shouldn’t comment on science, it is hilarious and makes deconverts from religion, see Dawkins’s Convert’s Corner.

        Mostly this is tedious. Planck has already succeeded in making “no big bang” ideas akin to ideas of Flat Earth ideas, or ‘completely failed models’ according to physicists. See my longish comment and why that is obvious – you can see it from the data graphs! You don’t even need to know about redshift and the easy observations, CMB data is enough.

        So go ahead, be a modern days flat earther. But don’t think we won’t laugh more or less openly.

        As for looking at strained coincidences with religious texts, it is both tedious and useless. The text you refer to (but why that one?) has two different stories (different time orders in Gen 1 and 2), so is obviously erroneous for anyone that can read. Can you read for understanding? Seems doubtful at this point.

        And note that we don’t know from the inflationary standard cosmology whether the process that resulted in a universe, inflation, has a beginning or not. It is past-timelike-incomplete, mening inflation could have lasted any chosen time.

        But what we do know from WMAP 9 year data release last year and now from Planck 4 year data release is that the universe must be the result of a spontaneous process (null energy universe) and _can’t_ be the result of magic.

        So again, those religious texts are seen as completely wrong on the facts.

      • Patreon
        Aqua4U says

        Here are the figures… http://arxiv.org/pdf/physics/0509163v1.pdf … I can’t say that I am exactly ‘conversant’ with these maths… and that is my greatest liability? Still… I wonder if the whole foundation would shake if one of the fractions were to change?

      • The Latinist says

        The article you linked to is about the effect of the movement of the observer on observed redshift in light emitted from an object at some a angle to the motion of the observer (it should be obvious that there will be a small redshift or blueshift induced by the relative motion of the observer). Its talking about a special case involving the angle at which this doppler shift will be zero due to relativistic effects.

        The important thing to remember here is that this effect would create blueshift in the direction of the observer’s motion and redshift in the direction. It cannot explain a uniform redshift in all directions relative to the motion of the observer. And it cannot explain why such a redshift would increase with distance from the observer.

        Here’s the thing: the fact that you don’t understand the math doesn’t make it incorrect. You’re basically arguing that your own ignorance weakens the evidence behind the theory. It should be obvious that that is not a valid argument.

      • Patreon
        Aqua4U says

        Today’s (04.08.13) APOD contains this red shift look up table and conversant variables.

  3. TheLastWord316 says

    Must every article on cosmology rely on the tired, trite “origins of the universe” rhetoric? Are all cosmologists ego maniacs? Is it possible to just describe the discovery, without all the heavy handed and completetly unscientific implications?

  4. Me says

    It is just so incredible what that one picture conjures up.

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