A Blog by Nadia Drake

How Will Science Confirm Those Cosmic Signals From the Infant Universe?

Announced on Monday, the detection of primordial gravitational waves – ripples in the fabric of the universe that tell us about the first trillionth of a trillionth of a trillionth of a second after the Big Bang – is already one of the biggest science discoveries of the year. In fact, it’s hard to think of something that can realistically top that.

That statement might sound a little hyperbolic, but it isn’t. Many cosmological ideas depend on the events in those very first, violent instants. Until now, we haven’t had much direct observational evidence pointing toward one theory or another.

“Most signs of what happened back then get obliterated,” says MIT physicist Frank Wilczek. “But gravitational waves interact so weakly with everything else that they propagate, they give us a record. What the team is seeing, or claims to be seeing, is the imprint of gravitational waves on the microwave background.”

A team using the BICEP2 detector at the South Pole found the waves’ imprints in the thermal radiation that’s left over from the Big Bang. Called the cosmic microwave background, this radiation forms the fabric that primordial gravitational waves press their fingerprints into, leaving swirly signatures that scientists call B-mode polarizations.

b_over_b_rect_BICEP2
Gravitational waves from inflation generate a faint but distinctive twisting pattern in the polarization of the CMB, known as a “curl” or B-mode pattern. (Harvard University)

These signatures are predicted by a theory known as cosmological inflation, proposed in 1980.

Inflation suggests that the universe we observe today – flat, smooth, relatively uniform – is the result of an unbelievably rapid and accelerating expansion that lasted for a fraction of a second after the Big Bang. Just how fast was it? Wilczek calculates that the acceleration of the expansion was somewhere in the neighborhood of 1048 centimeters/second2 – a number so big it’s basically impossible to comprehend. (Appropriately, inflation theory is connected to one of everyone’s favorite mind-boggling outcomes: The multiverse.)

The gravitational wave discovery has been described in news stories this week as “The Big One,” “a window back to almost the beginning of time,” “as big as it gets,” “worthy of a Nobel prize,” and “a grand slam.”

But along with those descriptions are qualifiers like “if the discovery is confirmed” and “if it is real” – statements that suggest caution is still needed.

That’s not because the data are shaky, necessarily, though there are some sticky spots that need clearing up. Among other things, three data points are sitting in a weird place and contamination by other sources of polarization cannot yet be definitively ruled out.

“The quality of the observing team is widely known to be excellent,” says Matt Strassler, a physicist at Harvard University. “But there are enough little funny things in the data, so I’d feel a lot better when a second independent team sees the same [signal] that BICEP2 sees where they are supposed to see it, and not the same funny things in the data which shouldn’t be there if the interpretation as gravitational waves is right.”

One of the principles of empirical science is that an experiment or an observation must be repeatable. You must be able to replicate a result. Too often, though, nobody bothers to independently verify another team’s science (there are some notable exceptions, like this one); in this case, I think we’ll see a number of teams looking to replicate the BICEP2 observations, and quickly. Here, scientists will be working to rule out other sources of B-mode polarizations, verify the signal in other patches of sky, and see if it’s observable on more than one microwave frequency.

“The result can be checked within the next year or two, in a number of ways,” says Neil Turok, director of the Perimeter Institute for Theoretical Physics, noting one significant caveat to the discovery. “It is very important to check that the B-mode signal is not contaminated by — or entirely due to — radiation from dust or particles in our galaxy.”

734356main_PIA13953
Artist’s concept of the Planck satellite. (ESA/NASA/JPL-Caltech)

Turok and others suggest that the Planck space observatory, launched in 2009 and tasked with mapping the cosmic microwave background, could help clear this up. Gravitational waves aren’t the only astrophysical phenomena that can produce B-mode polarizations in the observed background; others include atmospheric distortions, synchrotron radiation, and galactic dust.

Unlike BICEP2, Planck is in space, which means it has less to contend with in terms of Earth’s atmosphere mucking up observations of the microwave background. Planck also studies a larger patch of sky, and has collected a pile of data about polarization caused by dust and galactic foreground radiation. Those observations will be crucial for ruling out these other sources of B-mode signals. Now, the Planck team is analyzing its polarization data and preparing a release for later this year. “Planck should be able to confirm or refute this result,” says physicist Paul Steinhardt of Princeton University.

Mark Kamionkowski, a theoretical physicist at Johns Hopkins University, notes that while Planck could be helpful, it wasn’t designed specifically to look for B-mode polarization in the cosmic microwave background. As a result, he says, there are some tricky instrumental effects that will need to be accounted for.

Instead, Kamionkowski points to a handful of experiments that are designed specifically to look for gravitational wave signatures. Among these are SPIDER and EBEX, which both rely on balloon-borne detectors, launched into the south polar atmospheric vortex from McMurdo Station in Antarctica. For several weeks near the height of southern summer, the Antarctic sky hosts a cadre of enormous science balloons; these two will be looking specifically for the curled imprints of gravitational waves (others study such things as cosmic rays).

But SPIDER, EBEX, and BICEP are not alone at the South Pole. There’s also the South Pole Telescope, right next door to BICEP at Amundsen-Scott South Pole Station. Last summer, the team running an experiment there called SPTPol announced the detection of a different kind of cosmic gravitational signature, known as lensing. Now, the telescope is searching for primordial B-modes, although in a slightly different way than BICEP.

“I am not entirely sure, but there is a good chance that the B-mode signal could be detected in SPTPol in cross-correlation with BICEP2,” Kamionkowski said. “I hope that the SPTPol and BICEP2 people can get together to look into this ASAP.”

The BICEP2 telescope's focal plane consisting of an array of 512 superconducting bolometers, designed to operate at 0.25 K (0.25 degrees Celsius above absolute zero) in order to reduce thermal noise in the detectors. (Anthony Turner, JPL)
The BICEP2 telescope’s focal plane consisting of an array of 512 superconducting bolometers, designed to operate at 0.25 K (0.25 degrees Celsius above absolute zero) in order to reduce thermal noise in the detectors. (Anthony Turner, JPL)

Also at the South Pole is BICEP2’s successor, called the Keck Array. The array is more sensitive than BICEP2 – it has 2,560 detectors in it, compared to BICEP2’s 512 detectors. It also studies the sky at a different frequency (100GHz) than BICEP2 (150GHz), and will be looking to confirm the presence of gravitational wave signatures at the second frequency.

At slightly less southerly latitudes, in the Chilean Atacama, a cluster of other experiments are ready to peer closely at the cosmic microwave background. Here, ACTPol, CLASS, ABS, and POLARBEAR take advantage of the bone-dry sky to stare at radiation from the beginning of time.

Just last week, POLARBEAR released the first direct detection of B-modes due to gravitational lensing, a different kind of distortion in the background radiation that’s caused by structure (things like galaxies and clumps of dark matter) in the universe.

“We were focused on the lensing because we knew that signal was there. We wanted to see it and prove our instrument was working well,” says observational cosmologist Adrian Lee of the University of California, Berkeley. Now, the team is gearing up to study gravitational wave B-modes.

“POLARBEAR is going to be looking for this signal,” Lee says. “We’re really motivated to try and confirm the results they’re seeing.”

How long will it be until we know whether BICEP2’s data can be confirmed? It’s hard to say. Estimates range from a few weeks to a few years. Until those data come down, physicists will remain what Strassler describes as cautiously optimistic.

“We will look for confirmation from all of these experiments,” Kamionkowski says.

The Dark Sector Lab (DSL), located 3/4 of a mile from the Geographic South Pole, houses the BICEP2 telescope (left) and the South Pole Telescope (right). (Steffen Richter, Harvard University)
The Dark Sector Lab (DSL), located 3/4 of a mile from the Geographic South Pole, houses the BICEP2 telescope (left) and the South Pole Telescope (right). (Steffen Richter, Harvard University)

42 thoughts on “How Will Science Confirm Those Cosmic Signals From the Infant Universe?

  1. I think it is a wonderful discovery , now we sit back and wait til science repeats and proves it? and until, remain cautiously optimistic,we will all be waiting to see how this one turns out .!

  2. As well as the scientifically oriented doubts on the BICEP2 study: the software they used was written in such a way that it’s hard to verify that it does what it says it does.

  3. How much more time, money, and energy will Athiests spend to try and prove God doesn’t exist? All of this is to simply try and prove that God doesn’t exist, nothing else. Atheists are in the trillions of dollars now spent, kinda funny if you ask me.

  4. to Anonymous : Wow, where did that ignorant comment come from?! As we progress as a society, science discovers new things, and disap/proves many things. In time, we might discover your so-called God, might not have ever existed. What will you do then. Kinda funny how much people like you have wasted on ignorance…

  5. “That ignorant comment” came from fear of the unknown and the denial that God is far bigger and complexer than the human mind can conceive. I suspect that many of the scientists involved in such research are indeed “believers in God”!

  6. i think that believers are afraid ,that scientists want to take away from them Invisible Friend called God, on this level of astrophysics scientists are not even thinking about Imaginary Mighty Friend , they do just hard and super complex search for “Real True” which will benefit human kind for long run .

  7. Believers like to live in the bubble and no one can really get them out of there. And I don’t think it will change even if we figure out everything about the universe in next 1000 years. Human brain has evolved to fear (trait needed to survive, so mutation or genetic engineering cannot remove it) this fear will not let go of their imaginary friend for some. So they will always be there for as long as human race lives. Question is can we keep them away from the powerful offices so human kind as a whole doesn’t have to pay a price for ignorant bunch. Vote carefully !

  8. to all Atheists listen and listen carefully you pitiful little people
    GOD is not just a being he is undefiled existing before eternity invisible
    incomprehensible unsearchable unchanging cannot be calculated and surpassed by none.He created the universe he commanded it and it was done because he can create matter from energy and no matter how hard man tries he will never accomplish it get that through your thick skulls for once and for all.

  9. Science will DISCOVER more Evidence that There is GOD ALMIGHTY! NO COINCIDENCE; Everything created with Purpose , with harmony, golden ratio. Everything can not be result of co incidence or chance that we see it in the Universe is in aperfect ORDER! SCIENCE PROVES more evidence of ALNIGHTY GOD!

  10. I’m not a scientist, but I believe Einstein said that the speed of light was the ultimate, that nothing could travel faster. Did he make an exception for that instant when creation began?

  11. Great Blog. I will make a habit of checking this one out. Move over Phil Plait, there is a new blog in town.

    Creationists, lol. “invisible incomprehensible unsearchable unchanging cannot be calculated” Pretty much sums it up. Thank you for describing what we already know.

  12. Wheather you believe or disbelieve in God is up to you. However, if He exists, who’s to say in what way He created all of existence. Why couldn’t it be via the way we see things happening such as through the Big Bang or other types of physical phenominon? And as for the late Dr. Einstein, it wasn’t up to him to make exception for creation or the ultimate speed limit. Most of his work is theory.

  13. jim, good question because at first it appears to violate the speed of light limit. What is moving so fast is spacetime itself, not something traveling inside spacetime, therefore there is no violation. In other words our universe was expanding extremely quickly which, although quite mindblowing, is allowed by our understanding of physics and science!

  14. First, I’m a member of our local astronomy club and I have seven US patents in applied chemistry. That said, numerous stories like this one are too far fetched to appear in this magazine. Many of today’s astronomers, for various reasons, are intoxicated by speculation and hypothesis that are “proven” by some other hypothesis or speculation. I’m disappointed that so many publications choose to print their rubbish. Empirical science is discovering our solar system. Beyond that is a great void filled only with hot air.

  15. Nadia, I believe this is a great piece of scientific reporting that the general public needs to know about. However the general public is not scientifically trained & inquiring minds like mine would like you to please give us your own further interpretation & opinion on what this all means. We rely upon scientifically trained experts & journalists to explain to us all the meanings & implications of such matters. I would be interested in having you give us your own opinions & interpretations of whatever you report on in future. Thank you for a job well done but in future we would like to see your interpretations & opinions of these facts because we do not possess the expertise to properly evaluate all this information for ourselves. Your non-scientifically trained readers will certainly appreciate it!

  16. Goodness me, how the creationists/flat earthers waffle on about their delusions. But they are actually quite fun in the extent to which they get steamed up.
    Can’t wait for their next barrage.

  17. Isn’t it great that God created your brain to thirst for the complexity of our universe? As was mentioned in the article, ‘ the expansion number is so big it’s impossible to comprehend’. God is just that to non-believers. Until you have the personal experience of knowing God you will see believers as ignorant. Regardless, who created the Big Bang? It takes so much FAITH to believe the impossiblity of just our world coming together so perfectly. Coincidence? Nope…CREATED!

  18. Why “Either Or”? Why waste energy on anything other than admiring, appreciating, respecting , and protecting the amazing wonders we witness all around us, and being open to discovering and learning as much about it all as we can…(closed minds won’t be able to do this, because….they’re closed!)

  19. Would one of you creationist out there please explain why you think that faith trumps evidence and reason,
    .

  20. We perceive the universe through our senses, intuition and sensitivity. On the other hand, we connect with our inner self, shutting down our senses. As such, there are no absolute truths, just consensus of the majority. We have seen meta paradigms changes through history, from Newton to Eistein, from Tolomeo to Galileo. The Earth was once flat, and the Universe was believed to be expanding slowly, but is the contrary. Everyboby is entitled to he’s/his own opinion, thus I am flabbergasted by some of the, kind of disrespectful comments above.
    I believe that something drove the Big Bang, that it was not a random event. I am not a physicist or astronomer, just a simple mortal interested in these things. I understand the energy that existed today is the same energy that emerged from the Big Bang. If that is the case, then we are all interconnected as one flow of energy. For me, it is hard to believe that this is done in a chaotic way. Science and transcendence should, in my opinion, go hand in hand.
    There could be a time when we understand the empty matter that exists within atoms. Million of “fibers” that stick together atom’s particles and that have memory. Until them, I believe there is an “intention” behind them, call it God or whatever.

  21. This is marvelous. However, would someone kindly explain what the graphic wiggly interrupted lines mean and how they were derived.

    Thanks

  22. Is it that difficult or fearful to make the jump from something to nothing?
    To allow in the self doubt and search and learning? If the absence of
    a god is so terrifying, I say from what I have read above, that I would
    prefer the terrifying probability that we are alone in the universe. To those
    who cannot even contemplate this no wonder the question of a god
    or personal god is as necessary as it seems to be, pity myself with
    no belief and preferring this aloneness to all the platitudes and
    beliefs that abound in this great place? No, no pity. Give me the unknowns any old day.

  23. It is quite curious to me that while empiricists simply seek the truth through evidence, most being quite aware that the search is likely endless, it is still the search that is infinitely intriguing. If creationists are so entirely resigned to the faith that we are helpless and must concede all responsibility to something other than ourselves… why are ‘they’ reading an article like this? If mythology is your choice, so be it, you likely won’t find many scientists meddling in impossible stories written ‘a thousand’ years ago when humankind was merely a child with a child’s understanding of everything around them. Without exception creationists have accepted almost every other human advancement most notably technology and medicine, and yet continue to defer accountability for scientific, cosmological and even quantum discoveries for what seems to be… pride?. Please leave logical explanation and debate to those that find mathematics and science truly enlightening and creationists can continue to ‘hope for the best’

  24. It is quite curious to me that while empiricists simply seek the truth through evidence, most being quite aware that the search is likely endless, it is still the search that is infinitely intriguing. If creationists are so entirely resigned to the faith that we are helpless and must concede all responsibility to something other than ourselves… why are ‘they’ reading an article like this? If mythology is your choice, so be it, you likely won’t find many scientists meddling in impossible stories written ‘a thousand’ years ago when humankind was merely a child with a child’s understanding of everything around them. Without exception creationists have accepted almost every other human advancement most notably technology and medicine, and yet continue to defer accountability for scientific, cosmological and even quantum discoveries for what seems to be… pride? (please make the argument God created your 60″ plasma and your iPad.. please). Quite comically, (anonymous) scientific process has really nothing to do with disproving the existence of ‘God’ because God cannot be analytically studied. Please leave logical explanation and debate to those like Nadia that find mathematics and science truly enlightening and creationists can continue to ‘hope for the best’

  25. Well knowing that we are all an evolution, it comes down to a simple thought. I believe that if this discovery is confirmed with other analytical observations (essential), then whether true or not, the fact that the human being keeps realizing how smallER is our world in the grand scheme of things, leading to the concept of multiverse, and how evolution came about from the natural order of things looking to achieve equilibrium, IT IS ABSOLUTELY TRUE THAT THERE HAS TO BE A CREATOR. In what form, I truly cannot tell. The fact that God was identified and believed in by most of the worlds population, including by myself (along with hints like the Golden rule, E=mc2, … etc), THERE ABSOLUTELY HAS TO BE A CREATOR. What God believers look for is that God favors good intentions and achieving the Good, by the shear proof of the tendency of Nature to achieve equilibrium. So creationism, when tweaked, can absolutely accept the continual progress of science discoveries. BY THE WAY, someone mentioned Einstein work was mostly theory … Oh oh Einstein theories were physically proven with real observation. SO YES, THERE IS A GOD AND SCIENCE IS GREAT SO LONG AS PHYSICIST, CHEMISTS AND ENGINEERS EXIST TO VERIFY ITS RESULTS. GOD IS ESSENTIAL TO TURN ON THE CONCEPT OF CONSCIENCE AT AN EARLY IGNORANT STAGE WE CALL BIRTH, SO PEACE CAN HAVE A CHANCE TO EXIST AND FOSTER THE TENDENCY OF NATURE TO ACHIEVE EQUILIBRIUM.

  26. I enjoy immensely the implications of each of the writers comments. And maybe the truth will be known someday, but until that time, I wish each writer a thought of peace to each other’s positions…we are all star dust…

  27. I wonder if this discovery rules out the conjecture that ‘The Big Bang’ may have been the result of an improbable collision of two ultra-massive black holes in a super-universe that is beyond our ken.

    In this case, ‘ultra-massive’ implies a black-hole mass on the order of our entire universe.

    The hypothetical super-universe may have an existence that is unconstrained by time or space.

  28. This split-second expansion of the infant universe from nothing to the size of, say, the current size of the Milky Way galaxy 13.8 billion years ago is real. An object cannot travel through space at greater than c, light speed. But portions of the cosmos are receding from us right now at faster than light speed. The inflation that Guth theorized in1980 is real. But there are no multiverses. These gravitational waves too are real and will be confirmed.

  29. I’m just shocked about these comments…..Who am I? Where did I come from? Why am I here?
    God is about spiritual fruit, not religious nuts….
    Science Rocks!

  30. We have a tendency to simplify so in order to do so we started the use of the word GOD. Those things that we are not able to explain or define, so to explain them we came up with the concept that an entity GOD is responsible for it. We found it the best explanation to believe and now this belief of ours has just became a part of us of our conscience from which we can never get rid of, one of the reasons is that we scared

  31. Interesting, though consistent with the orthodoxy of the “big bang” hypothesis, the interpretation of these phenomena as “primordial” gravitational waves, from the first “trillionth of a trillionth of a trillionth of a second following the ‘big bang’”, is entirely conjecture, out of the imagination of the human mind making arbitrary connections between what is observable and what the human mind has chosen to believe, no matter how elaborately rationalized through arbitrary equations, etc. We humans are not only highly parochial throughout our affairs here on this speck of dust we call Earth within an infinite cosmos, we continue to be parochial in our dominant schools of thought about the cosmos itself. If you seriously contemplate for a moment, the “big bang” is born from the same human tendency at this stage of our primitive evolution, “scientific” or otherwise, the universe was Earth centered, the date of Earth’s creation, the universe has a beginning, etc. We have somewhat of a break from this dogma with the premise of a multiverse, though the mindset of one universe starting 13 plus billion years ago, with no prior existence, continues to be stubbornly defended by the dominant parochial human mind, where we just happen to be occupying the only universe which has existed throughout ALL time and space. An extreme example of senseless parochialism off the deep end, are the arguments attempting to “scientifically” rationalize the exact conditions necessary for life, are very unlikely to exist anywhere else in the “universe”, but here on Earth. We humans on this planet are barely a century beyond when we first began understanding the rudimentary structure of atomic particles, and while we are tempted to step back and take wonder at what we have accomplished since then, look also at what we have wrought with the primitive understanding of atomic energy. Our species has exhibited a painful lack of moral oversight and connection to our exploitation of these technologies, given our reckless poisoning of the planet and headlong rush into permanently contaminating our precious bio-sphere through senseless experimentation with nuclear power. The media cover-up continues with Fukushima as the most glaring example of avoiding any human responsibility for irreversibly devastating life on this planet, out of our own demented primitive vanity, believing we can control what we still do not understand…

Leave a Reply

Your email address will not be published. Required fields are marked *