Archive for the ‘astronomy’ category

Programming Note/Self Aggrandizement — Vulcan/Planet Nine Edition

January 29, 2016

Hey, all:  if you’ve got a moment this afternoon, I’ll be talking with Ira Flatow on Science Friday about The Hunt for Vulcan in the context of last week’s announcement about Planet Nine.

Radio_King_poster

I’ll be on in the second hour, starting at around 3:20 ET, maybe a couple of ticks before, and rabbiting on with Ira until about 3:38.  Some NPR stations fecklessly omit the second hour of Science Friday, so check local listings.  You can always catch it live or later at the Science Friday site.

While there may be better ways to spend 18 minutes of your life…there are surely worse ones too.  Come on down if you’ve time and the inclination.

Image: Poster for the film, The Radio King, 1922.

It Came From Planet Nine

January 26, 2016

There be dragons out there, waaaaay out there, in the dark, off the edge of the map.

Or rather, a virtuoso combination of observation and mathematical modeling has led to an exciting, in some ways joyously old-school prediction. Orbital oddities identified in a handful of distant Kuiper Belt Objects (KBOs) were subjected to the same kind of inquiry that allowed 19th century astronomers to infer Neptune from Uranus’s behavior, in what was widely understood to be a triumph of Isaac Newton’s “System of the World.”

William_Blake_-_Isaac_Newton_-_WGA02217

The new analysis, by two Caltech astronomers, theoretician Konstantin Batygin and the observer and Slayer-of-Pluto Michael Brown, has led to a broad outline of what to expect — a ~10 Earth mass planet travelling a very eccentric orbit that never comes closer to the sun than ~250 Earth-Sun distances, a unit of measure known as the Astronomical Unit.

I’m sure many of you saw the news about this last week.  Alexandra Witze in Nature had a  good write-up, as did Alan Burdick in The New Yorker.  (For those (quite a few) on the blog with the urge to read the original Batygin-Brown paper — go here.)

I couldn’t be more excited by the news.  I sometimes forget what an extraordinary run of solar system exploration I’ve been privileged to witness.  The variety we’ve found exists in our near-environment has leapt unbelievably, just in the last two or  three decades, and the richness and complexity of our own solar system is allowing us to make more sense of the process of planet and planetary system formation as more and more data emerges about exo-systems.

But for all that excitement, there’s something special about a new major planet.  As I write in The Hunt for Vulcan [Shameless Plug Here], the idea of a whole new world joining the neighborhood had enormous romantic power in the eighteenth and nineteenth century.  Arguably, given our present immersion in the imagined reality of multiple worlds, that romance cuts deeper still today.

But. ButButButButBut….it’s important to remember that a prediction, no matter how well supported, how seemingly necessary, isn’t the same thing as proof, as the discovery itself.  That’s what I tried to say in this essay on the subject.  A sample:

In 1846, the discovery of Neptune turned Le Verrier into a celebrity; for a time, he was the most famous man of science in the world. He went on an international tour and seized the moment to rise to the top of power in the highly contentious and hierarchical world of French astronomy. Batygin and Brown are taking a much more measured tack with Planet Nineand for good reason.  “We felt quite cautious about making the statement we made,” Batygin says.  Why such concern? Because, he says, “immediately after the detection of Neptune spurious claims of planets in outer solar system began to surface. We didn’t want to be another red herring.”

It wasn’t just the distant reaches of the solar system that tripped people up: 

Johannes_Vermeer_-_The_Astronomer_-_WGA24685

The only problem being, of course, that Vulcan was never there.

I’m much more hopeful for Batygin and Brown’s Planet Nine, but hopeful don’t pay the rent — or, as Batygin told me:

“If Newton is right, then I think we’re in pretty good shape,” says Batyagin. “We’re after a real physical effect that needs explanation. The dynamics of our model are persuasive.” And yet, he adds, that’s not enough. “Until Planet Nine is caught on camera it does not count as being real. All we have now is an echo.”

There’s a surfeit of terrestrial crazy to weigh us down.  It’s a relief, I find, to look up and out, and contemplate the ordered mysteries that so thoroughly dwarf Comrade Trump’s Yuuuuuggggge self conceit.

Images:  William Blake, Isaac Newton1795

Johannes Vermeer, The Astronomerc. 1668

For A Good Time In Cambridge…Tonight!c

November 3, 2015

So it’s here — Publication Day! The Hunt for Vulcan is now live.

There’s a bit of backstory on how the book came to be over at Gizmodo. Spoiler alert: Ta-Nehisi Coates bears part of the blame.

More backstory on Einstein’s role in all this here.

And last, tonight (in an hour and a half actually) this:

Levenson_BkTlk_flyer.REVISED

If that doesn’t read too well: I’ll be talking about the book with my colleague, the wonderful physicist and historian of science David Kaiser at 6 p.m. We’ll be at the MIT Museum — free and open to the public.

If you can’t make it, there will be alternatives.

And with that: shameless self promotion at least temporarily brought to a halt.

Mountains, Stars, Conflict

May 31, 2015

You’ll forgive, I hope, the self promotion here, but I want to draw attention to an essay I have in The Boston Globe today.

It’s about the controversy over the Thirty Meter Telescope (TMT) that is beginning to be constructed at the summit of Mauna Kea on the Big Island of Hawaii.  Mauna Kea is one of the world’s most significant sites for optical and near infrared astronomy — it’s already home to thirteen telescopes, including the two largest now in operation in the twin Keck instruments.

Jan_Vermeer_-_The_Astronomer

The TMT is designed to have a primary mirror three times the diameter of the Keck ten meter light buckets, with nine times the light gathering area.  Over the last century — which covers the era of large, mountaintop optical observatorys, each similar leap in telescope size has produced startling, powerful discoveries, and there’s every reason to expect the same of the TMT and its planned southern hemisphere counterparts.

But there’s a catch — or something more fundamental than a mere glitch.  Mauna Kea is a sacred site within the Hawaiian tradition, and an environmentally sensitive one, and opposition to TMT has grown from a point of tension to one of direct confrontation.  Construction of the TMT has been suspended, and the governor of Hawaii has called for the removal of a quarter of the existing observatories before the TMT itself begins operating.

In the midst of this confrontation, plenty of people have framed the two sides as another battle in the old war between science and religious belief.  I say in the Globe today that’s a mistake.  A taste:

….the TMT dispute shows where the science versus religion trope goes wrong. The Hawaiian protesters haven’t said that Mauna Kea’s telescopes are inherently impious, or that the data they collect is somehow wrong, or that Hawaiian mythology is a better account of the cosmos. Rather, the value, the joy, the need the observatories satisfy may indeed satisfy many, but not those continuing a Hawaiian tradition that allows its heirs to find connection with memory, with history, with nature — to achieve the same transcendence sought by those who find beauty in the measure of the universe.

That is: The TMT defenders and their opponents seek analogous rewards from their presence on Mauna Kea. Their conflict isn’t between the competing worldviews of science and religion, but between desires that are kin to each other — and that require the same physical space.

Check it out, if your Sunday afternoon tends that way.  Let me know what you think.

Image:  Johannes Vermeer,  The Astronomerc. 1668.

 

Randall Munroe Is On The Case

November 12, 2014

Just to add to the deliciousness of the day, xkcd is more or less live-cartooning the Rosetta landing on Comet 67P/Churyumov-Gerasimenko.* (h/t @edyong209)

Nothing in my day promises to be as challenging/exciting as what that craft (and its controllers) are doing.  You?

Robert_Salmon_-_South_Sea_Whale_Fishing_II

*That link is a little wonky.  If the cartoon (number 1446) doesn’t come up, click on the random button at the top, and then click again on the xkcd logo.  Sorry.)

Image:  Robert Salmon (how cool is it that a whale-fishery artist goes by the name Salmon?), South Sea Whale Fishing II, 1831.  Connection to this post made obvious at the xkcd link, btw.

 

I Like To Think Of This As The Universe Expressing An Opinion About Today’s Incarnation Of The Party Of Lincoln

October 2, 2014

I mean, this picture sure seems to make a cosmic viewpoint clear:

Keyhole_Nebula_-_Hubble_1999 crop

Ah well.  It’s back to work for your humble bloghost.

Image:  NASA, The Hubble Heritage Team (AURA/STScI) – Space Telescope Science Institute, Keyhole Nebula, crop of the feature known as “God’s Birdie,” 1999.

The Most Exciting Sentence I’ve Read This Decade…

March 18, 2014

…Would be this one:

 We find an excess of B -mode power over the base lensed- CDM expectation in the range 30 < ` <  150, inconsistent with the null hypothesis at a significance of >  5 δ.

That’s from the abstract to this paper, released yesterday, in which the team using the BICEP microwave detector at the South Pole reports on their analysis of three years of data taken from 2010-2012.

So what’s that all about?  It’s the best evidence yet that a fundamental pillar of Big Bang cosmology is right, that a concept named inflation does in fact describe what happened within the first instant of the formation of our universe.  Here’s how Alan Guth, the inventor of the idea describes it:

This theory is a new twist on big bang theory, proposing a novel picture of ho the universe behaved for the first minuscule fraction of a second of its existence.

The central feature of the theory is a brief period of extraordinary rapid expansion, of inflation,  which lasted for a time interval perhaps as short as 10^-30 seconds.  During this period the universe expanded by at least a factor of 10^25, and perhaps a great deal more. [Alan Guth, The Inflationary Universe, p. 14.]

Guth’s initial version of inflation theory has been refined significantly since its origins in the late 1970s, and in its modern form inflation has become part of the basic toolkit of cosmological investigation.  The universe we observe doesn’t make sense unless something occurred to explain, for just one example, the way the universe looks basically the same everywhere, when viewed on the largest scale.  Inflation as the idea has evolved has become the best available explanation (though there have been competing models) for this and other observed cosmological properties.  But the challenge has been to find some tell-tale sign that shows* that inflation actually happened.

It’s been clear for a long time where such signs might lie:  in the cosmic microwave background (CMB),  a snapshot of the cosmos taken at a moment called “recombination,” when the universe cooled down enough to permit electrons and protons to come together to form (mostly) neutral hydrogen atoms.  Photons — light — that up till that moment had been embraced in electromagnetic dances with charged particles were then unshackled to fly freely through space, carrying with them the traces of where they’d been just before that liberation — which came just 380,000 years after the big bang.

J.M.W._Turner_-_The_Beacon_Light

Over time (13.8 billionyears), thatextremely hot (energetic) spray of light has cooled to 2.7 Kelvins — 2.7 degrees above absolute zero — and is now detectable as those very long wavelengths of light called microwaves.  This  microwave background was identified in 1965 as a generalized blur covering the entire sky; increasingly sophisticated measurements have revealed more and more detail.  Over the last twenty fiveyears those observations have turned into a probe of what happened between the big bang and the flash of the CMB itself:  each newly precise measurement constrains the possible physics that gave rise to the details thus revealed.  Step by step, each new level of detail narrow the options for what could have occurred during the big bang era — and the chain of events that lead from cosmic origins to us becomes increasingly clear.

In the 1990s,  improving resolution of CMB images revealed spots on the sky where there is slightly more energy in that microwave background — corresponding to regions in the early universe with slightly more matter-energy than surrounding regions.  Such variations account for why there are lots of galaxies full of stars in some places, and vast voids in other:  over millions and billions of years, gravity can work on very slight variations in initial density to sort matter into that kind of pattern.

With the advance of both space and ground based microwave imagers, it’s become possible to sample the CMB in vastly greater detail, and thus uncover much more than the simple (easy for me to say) evolution of structure in the universe.  For example, CMB researchers have identified several acoustic peaks in the background — literally, the ringing of the early universe, pressure waves produced by the interaction of light and matter in the very early universe.  The particular properties of those peaks reveal basic facts about the universe — and help distinguish between different theories about how we get the cosmos we inhabit from the big bang whose traces we see in the CMB.

Before today, the state of play was that CMB results were most consistent with the  predictions of inflation, compared with other candidate ideas.  At the same time though, observations that are consistent-with are not the same as direct observations of the cosmological equivalent of the miscreant’s fingerprints on the knife.  That’s what the BICEP results deliver.

In simplest terms:  modern theories of cosmic inflation say that immediately after some tiny perturbation occurs that marks the birth of a universe, it gets pulled apart by inflation — which you can think of as negative gravity, a gravitational field that stretches space-time.  The inflationary episode is so powerful that it expands the infant universe by orders of magnitude in fractions of a second — as some say, inflation provides the bang in the big bang — and it’s so violent that as space-time undergoes such wild tugs, ripples form.  Those ripples are gravitational waves — predicted by Albert Einstein, inferred from the behavior of pulsars, but never detected directly.  An observation of such primordial fluctuations, variations in the strength of the gravitational field from point to point in the early universe, would offer the first direct glimpse of traces of an inflationary episode marking the birth of our cosmos.

And that’s what BICEPs results contain:  the team led by John Kovac at the Harvard – Smithsonian Center for Astrophysics, Clem Pryke at the University of Minnesota, Jamie Bock at Caltech/JPL, and Chao-Lin Kuo of Stanford and SLAC report the detection of the signature of gravity waves in the CMB with the properties corresponding to those predicted to be produced by inflation.

In slightly more detail, the BICEP experiment observed a particular pattern of polarization in the light (microwaves) of the CMB that inflation would be expected to produce.   (Many more details:   web resources from the BICEP team and partner institutions;  quick semi-technical gloss on the results from Sean B. Carroll;  Matt Strassler’s take; Dennis Overbye’s account in the NYT.)

One key caveat before the wind up:  this is one result from one group.  It is reported with great confidence (that five sigma claim).  But something this big needs independent confirmation — data from the Planck satellite for example, or more ground based observations from other microwave detectors.  This isn’t yet a done deal.

Such confirmation (or disproof) will come fairly quickly — a few years at most.

In the meantime, assuming the data do hold up, what would that mean (forgive me) more cosmically?

At the very least:  that we now understand in previously unattainable detail how our current habitat emerged from nothing (or better, “nothing”).  That the idea of a multiverse — other patches of space time that underwent an inflationary episode to form island universes of their own — has now gained a boost (if one patch of space-time can inflate, so could others)….

…or to put in mythic terms:  there is grandeur in this view of life (the cosmos).  Paraphrasing an old friend, astronomer Sandra Faber, with this new, richer, more fully realized picture of the birth of the universe we have once again enriched that creation story that only science tells, the one that connects the earth we inhabit today with a process of cosmic evolution that we now can trace back all the way to just the barest instant this side of the point of origin.

A good day.

*To a close approximation — this is physics.  You want certainty, become a mathematician.

[Thanks to Dr Katherine J. Mack of the University of Melbourne, aka @AstroKatie, who helped make sure no egregious errors slipped through.  Any mistakes, major or minor, that remain are mine, all mine.]

Image:  J. W. M. Turner, The Beacon Lightc. 1840

PS:  Bonus video showing one of the founding architects of inflation theory receiving news of the result:


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