Tag Archives: AAS225

Inflation: A cold little swoosh

Max Tegmark says that when he was applying for graduate school in physics, you’d best not mention the idea of parallel universes if you wanted to be accepted. A quarter century later Tegmark, an MIT physicist, stood before the 225th meeting of the American Astronomical Society making a plenary address titled “Inflation and Parallel Universes: Science or Fiction?” that made the concepts seem downright plausible.

Tegmark’s 2014 book, Our Mathematical Universe: My Quest for the Ultimate Nature of Reality, has sparked a lot of conversation inside and outside the scientific community. AAS Vice President Jack Burns of the University of Colorado says that made Tegmark a great pick for a talk at the biannual confab of astronomers.


MIT physicist Max Tegmark speaks at the American Astronomical Society meeting Jan. 7 in Seattle.

“Max’s approach to cosmology and big-picture questions have really been largely non-traditional, and I find that exciting,” Burns said in introducing Tegmark at the Jan. 7 meeting in Seattle. “Max is a rebel within a highly orthodox infrastructure that we all have to work in.”

Tegmark said that we as a species have a history of thinking too small.

“If we ask what we humans have figured out so far during the 13.8 billion years of our cosmic evolution, I think it’s one long story of underestimation,” Tegmark said. “We’ve again and again and again underestimated the size of our cosmos, realizing that everything that we thought existed was just a small part of something much grander: a planet, a solar system, a galaxy, clusters of galaxies, our observable universe, and maybe, as we’ll explore in this talk, a hierarchy of parallel universes.”

Tegmark said he wasn’t there to prove that inflation or parallel universes exist, but to correct some misconceptions. Most particularly, he poked at the notion that the existence of parallel universes cannot be tested scientifically. He contends that inflation predicts many phenomena that can be observed and measured. We wouldn’t throw out general relativity just because we have yet to observe a black hole directly. Likewise he said we shouldn’t dismiss parallel universes because we have yet to visit one.

Tegmark noted that inflation is more than just a mainstream idea now.

“It’s really, in my opinion, the most audacious idea we have, the most audacious extrapolation of physics so far,” he said. He noted that human growth interestingly parallels an inflationary early universe. Our number of cells double daily after conception, but the growth rates slows down soon after. The same happened with inflation. He points out that many people often think incorrectly that inflation followed the Big Bang.

“Inflation creates the Big Bang,” Tegmark said. “I think it’s more logical to say that before our Big Bang there was a cold little swoosh. That’s the early stages of inflation.”

“Inflation does this great party trick,” he added. “You can start with a tiny finite volume, less than a proton, and within there you can make an infinite volume inside the finite volume.”

Beings within a pocket may not be aware of what is going on outside.

“It’s pretty crazy, but that’s what you can do with general relativity,” Tegmark said. “Moreover, if there are many places where inflation doesn’t end, there’s nothing preventing you from having multiple, disconnected pockets like this.”

So how does Tegmark answer his own question? Are inflation and parallel universes science or fiction?

“Inflation has emerged as the most mainstream explanation for what happened early on,” he contended. “Whether it actually occurred and produced parallel universes is, of course, not yet settled. It remains controversial. But the key point that I want you to take away from this is that this controversy is clearly a scientific controversy, not a philosophical one, because the way it’s being settled is with data, not by people beating each other over the head with bottles in a bar.”

“2015 should bring much more clarity to what is going on,” Tegmark concluded. “Our universe is going to be an exciting place this year.”

The talk was engaging and the book should be a good read.

SDSS delivers a new look at the sky

Astronomers are crunching enormous amounts of data and amassing more all the time. It’s almost enough to make one think that there’s more data in the universe than the universe can hold, but that would be something of a paradox.

Another 100-terabyte chunk of data was delivered to the astronomical community Jan. 6. The Sloan Digital Sky Survey (SDSS) made the final release of the third epoch of its survey (SDSS-III) in Seattle at the 225th meeting of the American Astronomical Society. Data Release 12 (DR12) contains measurements of the properties of nearly half a billion stars and galaxies, making it one of the largest and richest databases in the history of astronomy. SDSS-III spent six years collecting that data using the 2.5-meter Sloan Foundation Telescope at Apache Point Observatory in New Mexico.

A still photo from an animated flythrough of the universe using SDSS data. This image shows our Milky Way Galaxy. The galaxy shape is an artist’s conception, and each of the small white dots is one of the hundreds of thousands of stars as seen by the SDSS. Image credit: Dana Berry / SkyWorks Digital, Inc. and Jonathan Bird (Vanderbilt University)

A still photo from an animated flythrough of the universe using SDSS data. This image shows our Milky Way Galaxy. The galaxy shape is an artist’s conception, and each of the small white dots is one of the hundreds of thousands of stars as seen by the SDSS. Image credit:
Dana Berry / SkyWorks Digital, Inc. and Jonathan Bird (Vanderbilt University).

“The most astonishing feature of the SDSS is the breadth of ground-breaking research it enables,” said Daniel Eisenstein of the Harvard-Smithsonian Center for Astrophysics and director of SDSS-III. “We’ve searched nearby stars for planets, probed the history of our Milky Way, and measured nine billion years of our universe’s accelerated expansion.”

DR12 includes data from several different surveys.

APOGEE (the Apache Point Observatory Galactic Evolution Experiment) looked in near-infrared wavelengths to see through obscuring dust clouds and mapped the distribution of 15 separate chemical elements in more than 100,000 stars, probing all regions of the Milky Way.

“That’s a huge amount of information,” said Steve Majewski of the University of Virginia, APOGEE’s principal investigator, “and each element reveals a different subplot in this galactic screenplay. Sometimes the interactions between the characters are quite surprising!”

MARVELS (the Multi-Object APO Radial Velocity Exoplanet Large-Area Survey) made repeated measurements of 3,000 stars to detect the back-and-forth motions that could reveal unseen orbiting planets.

“MARVELS is the first large-scale survey to measure these tiny motions for dozens of stars simultaneously,” said principal investigator Jian Ge of the University of Florida, “which means we can probe and characterize the full population of giant planets in ways that weren’t possible before.”

SDSS conference

Scientists involved with the Sloan Digital Sky Survey talk about their latest data release during a news conference Jan. 6 at the meeting of the American Astronomical Society in Seattle. L-R: Connie Rockosi, Daniel Eisenstein, Jian Ge, Steven Majewski, and Michael Wood-Vasey.

BOSS (the Baryon Oscillation Spectroscopic Survey) maps the fossil imprints of sound waves that filled the universe during the first half-million years after the Big Bang. The BOSS team is using those imprints to trace the expansion of the universe across nine billion years of cosmic history, with unprecedented precision.

SEGUE (the Sloan Extension for Galactic Understanding and Exploration) measured visible-light spectra of a quarter-million Milky Way stars.

“Data release 12 is the largest SDSS data release so far, it contains data that make more precise measurements than before, new kinds of data in new wavelength ranges for the survey facility, and new techniques for making those measurements,” said Connie Rockosi of U.C. Santa Cruz, the lead scientist for the Sloan telescope. Rockosi added that more science is certain to come now that all of that data has been released to the public.

And there’s more data to come. SDSS-III may be finished, but SDSS-IV began began a six-year mission last July to study cosmology, galaxies, and the Milky Way.

Rosetta mission: the end of the beginning

There have been a lot of amazing space missions that rank among the greatest engineering achievements of all time. The Rosetta mission has to be one of the most impressive ever. Rosetta traveled 10 years and more than four billion miles to rendezvous with comet 67P/Churyumov-Gerasimenko, a rubber-ducky-shaped pile of rocks 2.5 miles across that is zipping through space at about 84,000 miles an hour. It went into orbit around the comet and then it dropped a lander, Philae, that touched down on the surface of the comet back in November. Never mind that Philae didn’t stick the landing; that’s an quite an accomplishment.

Paul Weissman

Paul Weissman of JPL spoke about the Rosetta mission Monday at the 225th meeting of the American Astronomical Association.

Thus it was most enjoyable to hear from one of the Rosetta mission scientists, Paul Weissman of the NASA Jet Propulsion Laboratory, on Monday afternoon at the 225th meeting of the American Astronomical Society. Weissman gave a talk titled “Back to the Beginning: The Rosetta Mission to Comet Churyumov-Gerasimenko.”

“Doing space missions is a work of delayed gratification,” Weissman quipped, noting that they actually started work on Rosetta in 1996, and adding that there had been plans for such a mission for about a decade before that. They finally launched in 2004 and arrived at the comet, often shortened to C-G for obvious reasons, back in August.

“We had been ten years in space,” Weissman said. “It was really exciting to finally arrive at the comet.”

Rosetta carries 11 scientific instruments on board, and the Philae has ten. Even though Philae didn’t operate for long, between them the two craft have sent back a wealth of data.

“We’ve just been flooded with phenomenal results,” Weissman said.

Philae on C-G

Rosetta’s lander Philae on the surface of Comet 67P/Churyumov-Gerasimenko. One of the lander’s three feet can be seen in the foreground. The image is a two-image mosaic. Credit: ESA/Rosetta/Philae/CIVA

He shared a great many photographs from the mission and explained what all of the instruments have been observing. Among the interesting discoveries are that C-G is spinning faster than it did on its previous trip around the Sun, the result of the forces of outgassing of the comet’s material. There are pits on the nucleus that may be sink holes or outbursts; they’re not quite sure yet. They’ve detected water within the comet, and learned it is colder in its interior than on the surface. And the comet has about 74 percent porosity.

Some of the most fantastic returns are images taken by Philae from the surface of C-G that show exquisite detail.

“We’re looking at millimeter resolution of the surface of the comet,” Weissman noted, “something that’s just astounding in terms of what we’ve been able to do previously.”

Weissman holds out hope that they’ll get more from Philae, even though its batteries are dead because it landed in the shade.

“It may be possible to re-awaken the lander in May of this year,” he noted. “The solar panels that are exposed will gather enough energy to charge up the batteries, and we might have another shot of making measurements with the lander.”

Whether that works or not, there already is a great deal of data that mission scientists simply have not yet had time to analyze, and there’s more to come.

“This is the end of the beginning,” Weissman said, “because we have another whole year that we’re going to be in orbit, studying the nucleus and watching it get active. It reaches perihelion in August, so we’ll also watch it get inactive. And there’s talk of an extended mission into 2016.”

“This is just a remarkable mission.”

A dim view of the future of funding for space exploration

Dr. John M. Logsdon does not paint a very optimistic picture of the future of funding for space exploration. Logsdon, considered the dean of space policy and the founder of the Space Policy Institute at George Washington University, gave a talk titled “What Do We Expect of a Space Program?” today at the 225th meeting of the American Astronomical Society in Seattle.

John Logsdon

Dr. John Logsdon speaking Jan. 5, 2015, at the 225th meeting of the American Astronomical Society in Seattle.

Logsdon pulled the title of his lecture from a line in a Nixon Administration memo about the future of the space program. He says a big part of the problem is that, in more than four decades since the memo, the underlying question has not been adequately answered.

Logsdon pins much of the blame for the situation on President Nixon, who scaled back funding for NASA after the race to the Moon was won.

“The decisions he made from the ’69 through ’71 period, culminating in the January 5, 1972 announcement of the approval of the space shuttle, really characterized the program that NASA executed for the next 40-plus years, and basically avoided answering the question ‘What do we expect?’ by developing capabilities rather than seeking goals,” Logsdon said.

We had the answer under President Kennedy, according to Logsdon, when the goal was not just to put people on the Moon, but to achieve preeminence about all things in outer space.

“What is distinctive about Kennedy is he not only talked the talk, but he walked the walk,” Logsdon said. “He made a commitment of human and financial resources, peaceful but warlike mobilization of resources, to carry out that program of preeminence.”

Logsdon pointed out that the budget for NASA was $964 million when JFK urged the US to go the Moon; it had ballooned to $5.2 billion by 1965. Space science shared in the growth, its part of the NASA budget going from $131 million to $767 million in the same time frame.

Logsdon is tackling the history of presidential support for space exploration in his scholarship. He published John F. Kennedy and the Race to the Moon in 2010. His new book, After Apollo?: Richard Nixon and the American Space Program, is due out in March. The latter goes into great detail about Nixon’s approach and its lasting impact.

While NASA’s budget has fluctuated over the years, Logsdon sees a silver lining in the nation’s investment in science.

“The ups and downs in the overall NASA budget are not reflected in the budget for space science, which has shown a rather gradual but steady increase for the past 25 or 30 years, and has not vacillated,” he said. “Compared to the human spaceflight part of NASA, the space science, robotic science program, including Earth science, is in pretty good shape and is not being argued about.”

Logsdon served on the Columbia Accident Investigation Board, which opined in 2003 that NASA was being forced to do too much without adequate resources. He said that’s still a problem. The reason he doesn’t see a good solution ahead is that there are three possible responses, two of which he views as unlikely. He doesn’t foresee a great increase in our ambitions or some Sputnik-like incident that creates urgency about space. Nor does he anticipate a significant increase in spending, though that could depend in part on who the next president turns out to be.

“The most likely outcome is that we just keep muddling along, as we have since 1971, with a suboptimal program,” he concluded.

Further reading:

Shields up! Scientists find impenetrable barrier around Earth

Planet Earth has an invisible and impenetrable shield about 7,200 miles out in space that blocks killer electrons from coming in and zapping satellites and causing all sorts of other havoc in the wake of huge coronal mass ejections from the Sun. This barrier is a major discovery of the Radiation Belt Storm Probe and the Relativistic Electron Proton Telescope (REPT), launched by NASA in August of 2012.


Dr. Daniel Baker

Dr. Daniel Baker, REPT science lead at the Laboratory for Atmospheric and Space Physics at the University of Colorado, spoke about the mission and the discoveries today during his opening lecture at the 225th meeting of the American Astronomical Association in Seattle. The discoveries were detailed in an article in Nature back in November.

Baker has some great credentials for the project. He earned his Ph.D. under James Van Allen, whose gear first detected the Van Allen Belts—he preferred to call them zones—in 1957, in what many consider to be the first major scientific discovery of the space age. Baker also was an investigator on SAMPEX, a particle exploring mission that operated from 1992 until 2004.

There are twin REPT probes in a highly elliptical orbit around the Sun. One of the first major discoveries by REPT, according to Baker, was of a third Van Allen Belt, a storage belt of ultra-relativistic particles that remains constant while the other belts vary wildly because of solar events.

Interestingly enough, these particles don’t ever get in any closer than about 2.8 Earth radii. Baker says that was a strange discovery, as nature typically doesn’t like such sharp barriers, but observations so far have shown it to be an impenetrable.

“It looks, at least for the period of time, the couple of years, since the Van Allen probe launched that particles—ultrarelativistic electrons—can get in so far, they run into something almost like a glass wall, and can’t really get any further. This really was quite an interesting and fascinating puzzle.”

They looked into whether the phenomenon might be related to various actions of the Earth’s magnetic field, or even perhaps a reaction to radio waves broadcast from Earth, but those explanations fell short.

“We were left with the unsatisfying situation that very slow pitch-angle scattering and even slower radial diffusion can conspire to create this sharp gradient in the particle distributions,” Baker said. “To me, that’s not very satisfactory, but it seems to be the explanation.”

“I think its a subject now that our theoretical friends are struggling with and trying to understand and explain,” he added.

Baker says this new information is vitally important for those who may be studying x-rays from the Sun, synchrotron emissions from Jupiter, radio and x-ray emissions from distant nebulae, or extra-gallactic jets.

“All of these are visible because of energetic particles, electrons primarily, moving in strong magnetic fields,” he said. “Examining the details of how the accelerator that is so accessible to us in our own cosmic backyard can really give us much useful information about how acceleration processes work in these more removed systems.”

Baker says it is an exciting time in the field, with a great many instruments and missions collecting data.

“We have quite a golden age, in a sense, of measuring the properties of this entire magnetospheric system,” he said. “When we combine this information that we’re gathering now with the wonderful measurements of the Sun and the driving factors from the Sun, we really have the opportunity to make immense progress and to address the key questions that Van Allen and co-workers uncovered nearly 60 years ago.”

“The results from the Van Allen probes mission have in a real sense been rewriting the textbooks on many aspects of structure, acceleration, transport, and loss,” Baker concluded. “They’re giving us previously undreamt of capabilities.”