Will the Higgs Boson Destroy the Universe???

No.

The Higgs boson is not dangerous and will not destroy the universe.

The Higgs boson is a type of particle, a little ripple in the Higgs field. [See here for the Higgs FAQ.] This lowly particle, if you’re lucky enough to make one (and at the world’s largest particle accelerator, the Large Hadron Collider, only one in a trillion proton-proton collisions actually does so) has a brief life, disintegrating to other particles in less than the time that it takes light to cross from one side of an atom to another. (Recall that light can travel from the Earth to the Moon in under two seconds.) Such a fragile creature is hardly more dangerous than a mayfly.

Anyone who says otherwise probably read Hawking’s book (or read about it in the press) but didn’t understand what he or she was reading, perhaps because he or she had not read the Higgs FAQ.

If you want to worry about something Higgs-related, you can try to worry about the Higgs field, which is “ON” in our universe, though not nearly as “on” as it could be. If someone were to turn the Higgs field OFF, let’s say as a practical joke, that would be a disaster: all ordinary matter across the universe would explode, because the electrons on the outskirts of atoms would lose their mass and fly off into space. This is not something to worry about, however. We know it would require an input of energy and can’t happen spontaneously.  Moreover, the amount of energy required to artificially turn the Higgs field off is immense; to do so even in a small room would require energy comparable to that of a typical supernova, an explosion of a star that can outshine an entire galaxy and releases the vast majority of its energy in unseen neutrinos. No one, fortunately, has a supernova in his or her back pocket. And if someone did, we’d have more immediate problems than worrying about someone wasting a supernova trying to turn off the Higgs field in a basement somewhere.

Now it would also be a disaster if someone could turn the Higgs field WAY UP… more than when your older brother turned up the volume on your stereo or MP3 player and blew out your speakers. In this case atoms would violently collapse, or worse, and things would be just as nasty as if the Higgs field were turned OFF. Should you worry about this? Well, it’s possible this could happen spontaneously, so it’s slightly more plausible. But I do mean slightly. Very slightly. Continue reading

Be Careful Waking Up a Sleeping Blog

After a very busy few months, in which a move to a new city forced me to curtail all work on this website, I’m looking to bring the blog gradually out of hibernation.  [Wordsmiths and Latinists: what is the summer equivalent?] Even so, a host of responsibilities, requirements, grant  applications, etc. will force me to ramp up the frequency of posts rather slowly.  In the meantime I will be continuing for a second year as a Visiting Scholar at the Harvard physics department, where I am doing high-energy physics research, most of it related to the Large Hadron Collider [LHC].

Although the LHC won’t start again until sometime next year (at 60% more energy per proton-proton collision than in 2012), the LHC experimenters have not been sleeping through the summer of 2014… far from it.  The rich 2011-2012 LHC data set is still being used for new particle physics measurements by ATLAS, CMS, and LHCb. These new and impressive results are mostly aimed at answering a fundamental question that faces high-energy physics today: Is the Standard Model* the full description of particle physics at the energies accessible to the LHC?  Our understanding of nature at the smallest distances, and the future direction of high-energy physics, depend crucially on the answer.  But an answer can only be obtained by searching for every imaginable chink in the Standard Model’s armor, and thus requires a great diversity of measurements. Many more years of hard and clever work lie ahead, and — at least for the time being — this blog will help you follow the story.

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*The “Standard Model” is the theory — i.e., the set of mathematical equations — used to describe and predict the behavior of all the known elementary particles and forces of nature, excepting gravity. We know the Standard Model doesn’t describe everything, not only because of gravity’s absence, but because dark matter and neutrino masses aren’t included; and also the Standard Model fails to explain lots of other things, such as the overall strengths of the elementary forces, and the pattern of elementary particle types and particle masses. But its equations might be sufficient, with those caveats, to describe everything the LHC experiments can measure.  There are profound reasons that many physicists will be surprised if it does… but so far the Standard Model is working just fine, thank you.

BICEP2’s Cosmic Polarization: Published, Reduced in Strength

I’m busy dealing with the challenges of being in a quantum superposition, but you’ve probably heard: BICEP2’s paper is now published, with some of its implicit and explicit claims watered down after external and internal review. The bottom line is as I discussed a few weeks ago when I described the criticism of the interpretation of their work (see also here).

  • There is relatively little doubt (but it still requires confirmation by another experiment!) that BICEP2 has observed interesting polarization of the cosmic microwave background (specifically: B-mode polarization that is not from gravitational lensing of E-mode polarization; see here for more about what BICEP2 measured)
  • But no one, including BICEP2, can say for sure whether it is due to ancient gravitational waves from cosmic inflation, or to polarized dust in the galaxy, or to a mix of the two; and the BICEP2 folks are explicitly less certain about this, in the current version of their paper, than in their original implicit and explicit statements.

And we won’t know whether it’s all just dust until there’s more data, which should start to show up in coming months, from BICEP2 itself, from Planck, and from other sources. However, be warned: the measurements of the very faint dust that might be present in BICEP2’s region of the sky are extremely difficult, and the new data might not be immediately convincing. To come to a consensus might take a few years rather than a few months.  Be patient; the process of science, being self-correcting, will eventually get it straight, but not if you rush it.

Sorry I haven’t time to say more right now.

Some Higgs News from the LHCP Conference

Some news on the Higgs particle from the ATLAS and CMS experiments, the two general purpose experiments at the Large Hadron Collider. I just mention a few highlights. Continue reading

The BICEP2 Dust-Up Continues

The controversy continues to develop over the interpretation of the results from BICEP2, the experiment that detected “B-mode” polarization in the sky, and was hailed as potential evidence of gravitational waves from the early universe, presumably generated during cosmic inflation. [Here’s some background info about the measurement].

Two papers this week (here and here) gave more detailed voice to the opinion that the BICEP2 team may have systematically underestimated the possible impact of polarized dust on their measurement.  These papers raise (but cannot settle) the question as to whether the B-mode polarization seen by BICEP2 might be entirely due to this dust — dust which is found throughout our galaxy, but is rather tenuous in the direction of the sky in which BICEP2 was looking.

I’m not going to drag my readers into the mud of the current discussion, both because it’s very technical and because it’s rather vague and highly speculative. Even the authors of the two papers admit they leave the situation completely unsettled.  But to summarize, the main purpose and effect of these papers seems to be this:

Continue reading

A Bright Flash in the Neighborhood

NOTE ADDED: FALSE ALARM!  DISREGARD! HERE’S SWIFT’S DETAILED EXPLANATION AS TO WHY! with my own brief summary below.

Comparable in size to the Milky Way, our host galaxy, the Andromeda galaxy is the most distant object easily visible (in dark skies) to the naked eye; it lies 2.5 million light-years away.  About 2.5 million years ago, something in this distant star city went “boom”.  And in doing so it flashed, brightly, in high-energy photons — particles of light (or, more precisely, particles of electromagnetic radiation, of which visible light is just an example) — photons that carry many thousands of times more energy than do the photons that our eyes are designed to see.

File:Andromeda Galaxy (with h-alpha).jpg

The Andromeda Galaxy (photo from Creative Commons), which contains perhaps 100 billion stars or more. Something in here exploded a while back, and we just found out about it.

Some of these photons, after traveling for millions of years across space, arrived at Earth this afternoon.  They showed up in the Swift satellite’s telescopes, which are designed precisely to notice these things.  And Swift’s telescopes identified these photons as arriving from a location somewhere within Andromeda… within a globular cluster of stars, a tightly-knit neighborhood within the city that is Andromeda.  NOTE ADDED: Actually, a combination of low-probability events caused

  • a false alarm, of a sort that’s rare but not unexpected: a known object in Andromeda that emits X-rays appeared to brighten, as a result of electronic noise in Swift’s instruments (such noise is always present, in all scientific instruments, and it is normal to occasionally get a strong burst of it)
  • followed (due perhaps to a poorly-timed computer problem at Swift’s data center, which slowed the arrival of more complete information the Swift people know why but haven’t explained it in detail) by a delay in identifying this apparent brightening as a false alarm;

all of which is explained here.  The apparent brightening, which was rather mild, would in fact have been completely disregarded if it hadn’t occurred in Andromeda; for relatively nearby objects like Andromeda, the Swift team sets a low threshold for false alarms, because something real would be so amazingly important and exciting that we can’t afford to miss it. 

What caused this colossal explosion, perhaps the nearest of its type ever observed by modern astronomers?  That is the burning question that astronomers, and their friends in gravitational physics and particle physics, are aching to know.  It is likely that by tomorrow morning, and certainly within the next couple of days, we’ll know much more… perhaps we’ll even learn something of great importance.  NOTE ADDED: And indeed, we know.

For the moment, though, there’s lots of guessing, most all of which will turned out to be wrong.  (Maybe, some are speculating, this is a gamma-ray burst, perhaps caused by a merger of two neutron stars, with consequent bursts of neutrinos and gravitational waves that we might detect; but right now there’s no evidence for this, so don’t get your hopes up.)  You can read many breathless articles by following the Twitter hashtag #GRBm31.  Admittedly you might be better off without it.  NOTE ADDED: Yep.

But do stay tuned as the facts emerge.  The opportunity to observe such a nearby explosion is rare.  So this is certainly going to be interesting… and maybe, if we’re very lucky, it will be more than merely interesting…

NOTE ADDED: Actually, we were very unlucky, and it was completely uninteresting —except as an illustration that it can be very difficult, in the heat of a moment when data is sparse, to distinguish between something scientifically fascinating and a weird fluke.  Scientists do expect these things to happen sometimes.  Fortunately, science is self-correcting.  Even if Swift’s team hadn’t identified this signal as a fluke in their data, other telescopes would have been unable to find the object they’d identified, and doubts would quickly have emerged as a result.  If something’s real, everyone will see it.  

The lesson, in my view, is that when new scientific results are announced, be patient.  Give the experts a little time to check things, and don’t do science the way Twitter does.

And finally: if you are inclined to criticize the Swift team, you’re making a big mistake.  On the contrary, they did exactly what they were supposed to do, as quickly as they could.  Gamma-ray bursts [GRBs] are extremely rare and extremely valuable and extremely brief; Swift’s job is to let the scientific community know, as quickly as possible, that one may have been seen, so that others may look at it.  Inevitably, someone with such a job will occasionally give a false alarm.  Swift has discovered so many GRB’s, and made so many direct and indirect contributions to our knowledge about them and about other objects in the sky, that scientists, while disappointed that this was a false alarm, will certainly not view Swift as irresponsible.  

A week ago, regarding BICEP2’s results coming into question, Seth Zenz wrote a nice, short article on Why, in Science, it’s OK to be Wrong.  I recommend it.

Dark Matter Debates

Last week I attended the Eighth Harvard-Smithsonian Conference on Theoretical Astrophysics, entitled “Debates on the Nature of Dark Matter”, which brought together leading figures in astronomy, astrophysics, cosmology and particle physics. Although there wasn’t much that was particularly new, it was a very useful conference for taking stock of where we are. I thought I’d bring you a few selected highlights that particularly caught my eye. Continue reading

Will BICEP2 Lose Some of Its Muscle?

A scientific controversy has been brewing concerning the results of BICEP2, the experiment that measured polarized microwaves coming from a patch of the sky, and whose measurement has been widely interpreted as a discovery of gravitational waves, probably from cosmic inflation. (Here’s my post about the discovery, here’s some background so you can understand it more easily. Here are some of my articles about the early universe.)  On the day of the announcement, some elements of the media hailed it as a great discovery without reminding readers of something very important: it’s provisional!

From the very beginning of the BICEP2 story, I’ve been reminding you (here and here) that it is very common for claims of great scientific discoveries to disappear after further scrutiny, and that a declaration of victory by the scientific community comes much more slowly and deliberately than it often does in the press. Every scientist knows that while science, as a collective process viewed over time, very rarely makes mistakes, individual experiments and experimenters are often wrong.  (To its credit, the New York Times article contained some cautionary statements in its prose, and also quoted scientists making cautionary statements.  Other media outlets forgot.)

Doing forefront science is extremely difficult, because it requires near-perfection. A single unfortunate mistake in a very complex experiment can create an effect that appears similar to what the experimenters were looking for, but is a fake. Scientists are all well-aware of this; we’ve all seen examples, some of which took years to diagnose. And so, as with any claim of a big discovery, you should view the BICEP2 result as provisional, until checked thoroughly by outside experts, and until confirmed by other experiments.

What could go wrong with BICEP2?  On purely logical grounds, the BICEP2 result, interpreted as evidence for cosmic inflation, could be problematic if any one of the following four things is true:

1) The experiment itself has a technical problem, and the polarized microwaves they observe actually don’t exist.

2) The polarized microwaves are real, but they aren’t coming from ancient gravitational waves; they are instead coming from dust (very small grains of material) that is distributed around the galaxy between the stars, and that can radiate polarized microwaves.

3) The polarization really is coming from the cosmic microwave background (the leftover glow from the Big Bang), but it is not coming from gravitational waves; instead it comes from some other unknown source.

4) The polarization is really coming from gravitational waves, but these waves are not due to cosmic inflation but to some other source in the early universe.

The current controversy concerns point 2. Continue reading