News

Apr
30
2019
Baylor University seniors - Garrett Williams, a physics and chemistry major, and Catherine Arndt, a physics major - have been selected to participate in the 2019 NSF Graduate Research Fellowship Program. Catherine will pursue her doctorate in the Applied Physics Graduate Program at Rice University, while Garrett will attend the Physics Ph.D. program at the University of Illinois in Urbana-Champagne, the top-ranked university in the country for condensed matter physics. Congratulations!
Mar
6
2019
Baylor graduate student, Jingyi Yang awarded prestigious OSA (Optical Society of America) Emil Wolf Outstanding Student Paper Award. Congratulations!
Mar
6
2019
Dr. Howard Lee received the NSF MRI award to acquire an Ebeam lithography system. Congratulations!
Jan
1
2019
Baylor postdoc, Dr. Joe Pastika, and Baygraduate student, Caleb Smith and Chris Madrid, who work in the experiment high energy physics group, received prestigious scholarships/awards. Congratulations!
Dec
18
2018
By Don Lincoln, Senior Scientist, Fermi National Accelerator Laboratory; Adjunct Professor of Physics, University of Notre Dame

Black holes may not have singularities at their center. Instead, the matter they suck in may be spit out across the universe at some time in the future, a new theory suggests.
Dec
17
2018
“Far Out!”

It’s official: astronomers found a new dwarf planet in our solar system — and it’s the most distant object ever observed in our solar system.
Dec
13
2018
Rings Of Fire

If you’re in the market for a new desktop wallpaper, we have 20 suggestions.

A protoplanetary disk is the ring of dust and gas that surrounds a young star. As time passes, the material in the disk begins to coalesce into larger and larger objects, forming everything from asteroids to entire planets.
Dec
10
2018
Half of the people pursuing careers as scientists at higher education institutions will drop out of the field after five years, according to a new analysis from researchers at Indiana University Bloomington.
Dec
7
2018
Scientists started watching crystals sparkle in the 1990s. Those crystals sparkled more in the summer, which researchers took as evidence of dark matter. But those scientists were probably wrong, new research suggests.
Dec
3
2018
Scientists announced four new observations of gravitational waves - ripples in the fabric of spacetime - from the final moments of black hole mergers.
Dec
3
2018
Scientists from the Theory Department of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science (CFEL) in Hamburg, Germany have shown through theoretical calculations and computer simulations that the force between electrons and lattice distortions in an atomically thin two-dimensional superconductor can be controlled with virtual photons. This could aid the development of new superconductors for energy-saving devices and many other technical applications.
Nov
14
2018
Scientists think there's a "dark matter hurricane" heading toward Earth. In fact, it might even be blowing through us already.
Nov
14
2018
Sitting about 6 light-years away from our sun, the red dwarf named Barnard's star is the nearest solitary star to our solar system and the fastest-moving star in our night sky. It's also really wobbly.
Nov
5
2018
For a few minutes on Jan. 23, 2017, the coldest spot in the known universe was a tiny microchip hovering 150 miles over Kiruna, Sweden.

The chip was small — about the size of a postage stamp — and loaded with thousands of tightly-packed rubidium-87 atoms. Scientists launched that chip into space aboard an unpiloted, 40-foot-long (12 meters) rocket, then bombarded it with lasers until the atoms inside it cooled to minus 459.67 degrees Fahrenheit (minus 273.15 degrees Celsius) — a fraction of a fraction of a degree above absolute zero, the coldest possible temperature in nature.
Sep
20
2018
Drs. Lorin Matthews, Bryan Shaw, Seung Kim, Caleb Martin and Howard Lee have received prestigious CAREER Awards from the National Science Foundation for their work in a wide variety of fields.
Sep
19
2018
In a multi-‘cat’ experiment, the textbook interpretation of quantum theory seems to lead to contradictory pictures of reality, physicists claim.
Aug
30
2018
When a dead star meets a giant black hole, something weird can happen. The astronomical meeting can create a zombie.

Upcoming research in the Astrophysical Journal outlines what might happen if a white dwarf encounters an intermediate-mass black hole. Its conclusion: The violent pull of the black hole could, in theory, reignite fusion inside the dead star.
Aug
29
2018
If you’ve been a science fan for the last few years, you’re aware of the exciting results to emerge from the Large Hadron Collider (LHC), which in 2012 found the Higgs boson, the subatomic particle responsible for giving mass to fundamental subatomic particles.

Today, physicists have another exciting announcement to add to the Higgs saga: They have made the first unambiguous observation of Higgs bosons decaying into a matter-antimatter pair of bottom quarks. Surprisingly, the Higgs bosons decay most often in this way.
Aug
8
2018
Next time you eat a blueberry (or chocolate chip) muffin consider what happened to the blueberries in the batter as it was baked. The blueberries started off all squished together, but as the muffin expanded they started to move away from each other. If you could sit on one blueberry you would see all the others moving away from you, but the same would be true for any blueberry you chose. In this sense galaxies are a lot like blueberries.
Aug
3
2018
Researchers looking for signals from technologically advanced aliens pick up countless strange pings — but so far, nothing has convinced them that a message really came from aliens.
Aug
2
2018
Spectacular time-lapse footage from the European Southern Observatory's Very Large Telescope (VLT) in Chile captures stars orbiting the black hole at the center of the Milky Way, including one daring star that circles incredibly close.
Aug
1
2018
With every new exoplanet discovered, the same question arises: Could this world host life?

The default way scientists first approach that question is to check if the planet lies in the so-called habitable zone, the range of distances from a star in which a planet can hold liquid water on its surface. But water alone doesn't make life, so in a new paper, a team of scientists looked at another aspect of habitability: whether a planet receives enough ultraviolet radiation to create life's building blocks.
Aug
1
2018
NASA has cooled a cloud of rubidium atoms to ten-millionth of a degree above absolute zero, producing the fifth, exotic state of matter in space. The experiment also now holds the record for the coldest object we know of in space, though it isn't yet the coldest thing humanity has ever created. (That record still belongs to a laboratory at MIT.)

The Cold Atom Lab (CAL) is a compact quantum physics machine, a device built to work in the confines of the International Space Station (ISS) that launched into space in May. Now, according to a statement from NASA, the device has produced its first Bose-Einstein condensates, the strange conglomerations of atoms that scientists use to see quantum effects play out at large scales.

"Typically, BEC experiments involve enough equipment to fill a room and require near-constant monitoring by scientists, whereas CAL is about the size of a small refrigerator and can be operated remotely from Earth," Robert Shotwell, who leads the experiment from the Jet Propulsion Laboratory, said in the statement.
Despite that difficulty, NASA said, the project was worth the effort. A Bose-Einstein condensate on Earth is already a fascinating object; at super-low temperatures, atoms' boundaries blend together, and usually-invisible quantum effects play out in ways scientists can directly observe. But cooling clouds of atoms to ultra-low temperatures requires suspending them using magnets or lasers. And once those magnets or lasers are shut off for observations, the condensates fall to the floor of the experiment and dissipate.

In the microgravity of the ISS, however, things work a bit differently. The CAL can form a Bose-Einstein condensate, set it free, then have a significantly longer time to observe it before it drifts off, NASA wrote — as long as 5 or 10 seconds. And that advantage, as Live Science previously reported, should eventually allow NASA to create condensates far colder than any on Earth. As the condensates expand outside their container, they cool further. And the longer they have to cool, the colder they get.

Originally published on Live Science.
Jul
30
2018
Scientists working on the Large Hadron Collider (LHC) achieved yet another first Wednesday (July 25), revving full-blown atoms (with electrons oribiting them) up to near the speed of light.

The question of whether these were truly the first "atoms" that humans have accelerated to these speeds is a bit semantic; The LHC accelerates atomic nuclei of one sort or another all the time. (That's why folks sometimes call the giant machine, run by the European Center for Nuclear Research, or CERN, an "atom smasher.") But this is the first time those nuclei have had electrons orbiting them. In this case, CERN explained in a press release, the researchers accelerated lead nuclei, each orbited by a single electron, in a relatively low-energy beam for "about an hour."

Then they "ramped the LHC up to its full power and maintained the beam for about two minutes before it was ejected." [Photos: The World's Largest Atom Smasher (LHC)]


What is a Nerve Agent?
Simply put, nerve agents stop the central nervous system from communicating with the muscles, organs and glands it needs to keep your body's internal machinery running smoothly.

n a follow-up test, they maintained the full-power beam for two hours with a smaller group of atoms.

Michaela Schaumann, an LHC physicist, said in a statement that accelerating atoms with electrons is challenging because, "it's really easy to accidentally strip off the electron. ... When that happens, the nucleus crashes into the wall of the beam pipe because its charge is no longer synchronised with the LHC's magnetic field."

The multi-billion-Euro experiment has safeguards to protect itself, she said, so if a beam becomes unstable it automatically gets dumped in order to protect the LHC.

However, CERN said, the complex atom beams turned out to be more stable than expected. That's good news, Schaumann said, because it opens the door to a host of new experiments. The most interesting? Using the complex atoms as gamma-ray sources. When the electrons move from high- to low-energy states, they emit photons (light particles). And at the LHC's speeds, those photons would have the wavelengths and energies of gamma rays, which can be difficult to produce in a lab.

Originally published on Live Science.
Jul
30
2018
The problem with string theory, according to some physicists, is that it makes too many universes. It predicts not one but some 10500versions of spacetime, each with their own laws of physics. But with so many universes on the table, how can the theory explain why ours has the features it does?

Now some theorists suggest most—if not all—of those universes are actually forbidden, at least if we want them to have stable dark energy, the supposed force accelerating the expansion of the cosmos. To some, eliminating so many possible universes is not a drawback but a major step forward for string theory, offering new hope of making testable predictions. But others say the multiverse is here to stay, and the proposed problem with all those universes is not a problem at all.

The debate was a hot topic at the end of June in Japan, where string theorists convened for the conference Strings 2018. "This is really something new and it's led to a controversy within the field," says Ulf Danielsson, a physicist at Uppsala University in Sweden. The conversation centers on a pair of papers posted on the preprint server arXiv last month taking aim at the so-called “landscape” of string theory—the incomprehensible number of potential universes that result from the many different solutions to string theory's equations that produce the ingredients of our own cosmos, including dark energy. But the vast majority of the solutions found so far are mathematically inconsistent, the papers contend, putting them not in the landscape but in the so-called "swampland" of universes that cannot actually exist. Scientists have known many solutions must fall in this swampland for years, but the idea that most, or maybe all, of the landscape solutions might live there would be a major change. In fact, it may be theoretically impossible to find a valid solution to string theory that includes stable dark energy, says Cumrun Vafa, a Harvard University physicist who led the work on the two papers.
Lost in the Multiverse

String theory is an attempt to describe the whole universe under a single "theory of everything" by adding extra dimensions of spacetime and thinking of particles as miniscule vibrating loops. Many string theorists contend it is still the most promising direction for pursuing Albert Einstein's dream of uniting his general theory of relativity with the conflicting microscopic world of quantum mechanics. Yet the notion of a string theory landscape that predicts not just one universe but many has put some physicists off. "If it's really the landscape, in my view it's death for the theory because it loses all predictive value," says Princeton University physicist Paul Steinhardt, who collaborated on one of the recent papers. "Literally anything is possible." To Steinhardt and others, the newfound problems with dark energy offer string theory a way out. "This picture with a big multiverse could be mathematically wrong," Danielsson says. "Paradoxically this makes things much more interesting because that means string theory is much more predictive than we thought it was."

Some string theorists such as Savdeep Sethi of the University of Chicago welcome the reevaluation that is happening now. "I think this is exciting," he says. "I've been a skeptic of the landscape for a long time. I'm really happy to see the paradigm shift away from this belief that we have this proven set of solutions." But not everyone buys the argument that the landscape actually belongs in the swampland—especially the research team that established one of the earliest versions of the landscape in the first place back in 2003, which goes by the acronym KKLT after the scientists' last names. "I think it's very healthy to make these conjectures and check what other things could be going on but I don't see either theoretical or experimental reasons to take such a conjecture very seriously," says KKLT member Shamit Kachru of Stanford University. And Eva Silverstein, a Stanford physicist who also helped build the early landscape models, likewise doubts Vafa and his colleagues' argument. "I think the ingredients KKLT use and the way they put them together is perfectly valid," she says. Juan Maldacena, a theorist at the Institute for Advanced Study, says he also still supports the idea of string theory universes with stable dark energy.

And many theorists are perfectly happy with the string theory multiverse. "It is true that if this landscape picture is correct, the bit of the universe we're in compared to the multiverse will be like our solar system within the universe," Kachru says. And that is a good thing, he adds. Johannes Kepler originally sought a fundamental reason for why Earth lies the distance it does from the sun. But now we know the sun is just one of billions of stars in the galaxy, each with its own planets, and the Earth–sun distance is simply a random number rather than a result of some deep mathematical principle. Likewise, if the universe is one of trillions within the multiverse, the particular parameters of our cosmos are similarly random. The fact these numbers seem perfectly fine-tuned to create a habitable universe is a selection effect—humans will of course find themselves in one of the rare corners of the multiverse where it is possible for them to have evolved.

The Accelerating Universe

If it is true string theory cannot accommodate stable dark energy, that may be a reason to doubt string theory. But to Vafa it is a reason to doubt dark energy—that is, dark energy in its most popular form, called a cosmological constant. The idea originated in 1917 with Einstein and was revived in 1998 when astronomers discovered that not only is spacetime expanding—the rate of that expansion is picking up. The cosmological constant would be a form of energy in the vacuum of space that never changes and counteracts the inward pull of gravity. But it is not the only possible explanation for the accelerating universe. An alternative is "quintessence," a field pervading spacetime that can evolve. "Regardless of whether one can realize a stable dark energy in string theory or not, it turns out that the idea of having dark energy changing over time is actually more natural in string theory," Vafa says. "If this is the case, then one can measure this sliding of dark energy by astrophysical observations currently taking place."

So far all astrophysical evidence supports the cosmological constant idea, but there is some wiggle room in the measurements. Upcoming experiments such as Europe's Euclid space telescope, NASA's Wide-Field Infrared Survey Telescope (WFIRST) and the Simons Observatory being built in Chile's desert will look for signs dark energy was stronger or weaker in the past than the present. "The interesting thing is that we're already at a sensitivity level to begin to put pressure on [the cosmological constant theory]." Steinhardt says. "We don't have to wait for new technology to be in the game. We're in the game now." And even skeptics of Vafa's proposal support the idea of considering alternatives to the cosmological constant. "I actually agree that [a changing dark energy field] is a simplifying method for constructing accelerated expansion," Silverstein says. "But I don't think there's any justification for making observational predictions about the dark energy at this point."

Quintessence is not the only other option. In the wake of Vafa's papers, Danielsson and colleagues proposed another way of fitting dark energy into string theory. In their vision our universe is the three-dimensional surface of a bubble expanding within a larger-dimensional space. "The physics within this surface can mimic the physics of a cosmological constant," Danielsson says. "This is a different way of realizing dark energy compared to what we've been thinking so far."

A Beautiful Theory

Ultimately the debate going on in string theory centers on a deep question: What is the point of physics? Should a good theory be able to explain the particular characteristics of the universe around us or is that asking too much? And when a theory conflicts with the way we think our universe works, do we abandon the theory or the things we think we know?

String theory is incredibly appealing to many scientists because it is "beautiful"—its equations are satisfying and its proposed explanations elegant. But so far it lacks any experimental evidence supporting it—and even worse, any reasonable prospects for gathering such evidence. Yet even the suggestion string theory may not be able to accommodate the kind of dark energy we see in the cosmos around us does not dissuade some. "String theory is so rich and beautiful and so correct in almost all the things that it's taught us that it's hard to believe that the mistake is in string theory and not in us," Sethi says. But perhaps chasing after beauty is not a good way to find the right theory of the universe. "Mathematics is full of amazing and beautiful things, and most of them do not describe the world," physicist Sabine Hossenfelder of the Frankfurt Institute for Advanced Studies wrote in her recent book, Lost in Math: How Beauty Leads Physics Astray (Basic Books, 2018).

Despite the divergence of opinions, physicists are a friendly bunch, and are united by their common goal of understanding the universe. Kachru, one of the founders of the landscape idea, worked with Vafa, the landscape's critic, as his undergraduate advisor—and the two are still friends. "He asked me once if I'd bet my life these [landscape solutions] exist," Kachru says. "My answer was, 'I wouldn't bet my life but I'd bet his!'"

Additional reporting by Lee Billings.

This story was provided by Astrobiology Magazine, a web-based publication sponsored by the NASA astrobiology program.
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