Speed of universe’s expansion remains elusive


Unless you are a recent arrival from another universe, you’ve no doubt heard that this one is expanding. It’s getting bigger all the time. What’s more, its growth rate is accelerating. Every day, the universe expands a little bit faster than it did the day before.

Those day-to-day differences are negligible, though, for astronomers trying to measure the universe’s expansion rate. They want to know how fast it is expanding “today,” meaning the current epoch of cosmic history. That rate is important for understanding how the universe works, knowing what its ultimate fate will be and even what it is made of. After all, the prime mission of the Hubble Space Telescope when it was launched in 1990 was to help determine that expansion rate (known, not coincidentally, as the Hubble constant, named for the astronomer Edwin Hubble).

Since then evidence from Hubble (the telescope) and other research projects has established a reasonably precise answer for the Hubble constant: 73, in the units commonly used for this purpose. (It means that two independent astronomical bodies separated by 3.26 million light-years will appear to be moving away from each other at 73 kilometers per second.) Sure, there’s a margin of error, but not much. The latest analysis from one team, led by Nobel laureate Adam Riess, puts the Hubble constant in the range of 72–75, as reported in a paper posted online January 3. Considering that as late as the 1980s astronomers argued about whether the Hubble constant was closer to 40 or 90, that’s quite an improvement in precision.

But there’s a snag in this success. Current knowledge of the universe suggests a way to predict what the Hubble constant ought to be. And that prediction gives a probable range of only 66–68. The two methods don’t match.

“This is very surprising, I think, and very interesting,” Riess, of the Space Telescope Science Institute in Baltimore, said in a talk January 9 at a meeting of the American Astronomical Society.

It’s surprising because astrophysicists and cosmologists thought they had pretty much figured the universe out. It’s made up of a little bit of ordinary matter, a lot of some exotic “dark matter” of unknown identity, and even more of a mysterious energy permeating the vacuum of space, exerting gravitational repulsion. Remember that acceleration of the expansion rate? It implies the existence of such energy. Because nobody knows what it is, people call it “dark energy,” while suspecting that its real name is lambda, the Greek letter that stands for “cosmological constant.” (It’s called a constant because any part of space should possess the same amount of vacuum energy.) Dark energy contributes something like 70 percent of the total mass-energy content of the universe, various lines of evidence indicate.

If all that’s right, then it’s not all that hard to infer how fast the universe should be expanding today. You just take the recipe of matter, dark matter and dark energy and add some ghostly subatomic particles known as neutrinos. Then you carefully measure the temperature of deep space, where the only heat is the faint glow remaining from the Big Bang. That glow, the cosmic microwave background radiation, varies slightly in temperature from point to point. From the size of those variations, you can calculate how far the radiation from the Big Bang has been traveling to reach our telescopes. Combine that with the universe’s mass-energy recipe, and you can calculate how fast the universe is expanding. (You can, in fact, do this calculation at home with the proper mathematical utensils.)

An international team’s project using cosmic microwave background data inferred a Hubble constant of 67, substantially less than the 73 or 74 based on actually measuring the expansion (by analyzing how the light from distant supernova explosions has dimmed over time).

When this discrepancy first showed up a few years ago, many experts believed it was just a mirage that would fade with more precise measurement. But it hasn’t.

“This starts to get pretty serious,” Riess said at the astronomy meeting. “In both cases these are very mature measurements. This is not the first time around for either of these projects.”

One commonly proposed explanation contends that the supernova studies are measuring the local value of the Hubble constant. Perhaps we live in a bubble, with much less matter than average, skewing expansion measurements. In that case, the cosmic microwave background data might provide a better picture of the “global” expansion rate for the whole universe. But supernovas observed by the Hubble telescope extend far enough out to refute that possibility, Riess said.

“Even if you thought we lived in a void…, you still are basically stuck with the same problem.”

Consequently it seems most likely that something is wrong with the matter-energy recipe for the universe (technically, the cosmological standard model) used in making the expansion rate prediction. Maybe the vacuum energy driving cosmic acceleration is not a cosmological constant after all, but some other sort of field filling space. Such a field could vary in strength over time and throw off the calculations based on a constant vacuum energy. But Riess pointed out that the evidence is growing stronger and stronger that the vacuum energy is just the cosmological constant. “I would say there we have less and less wiggle room.”

Another possibility, appealing to many theorists, is the existence of a new particle, perhaps a fourth neutrino or some other relativistic (moving very rapidly) particle zipping around in the early universe.

“Relativistic particles — theorists have no trouble inventing new ones, ones that don’t violate anything else,” Riess said. “Many of them are quite giddy about the prospect of some evidence for that. So that would not be a long reach.”

Other assumptions built into the current cosmological standard model might also need to be revised. Dark matter, for example, is presumed to be very aloof from other forms of matter and energy. But if it interacted with radiation in the early universe, it could have an effect similar to that of relativistic particles, changing how the energy in the early universe is divided up among its components. Such a change in energy balance would alter how much the universe expands at early times, corrupting the calibrations needed to infer the current expansion rate.

It’s not the first time that determining the Hubble constant has provoked controversy. Edwin Hubble himself initially (in the 1930s) vastly overestimated the expansion rate. Using his rate, calculations indicated that the universe was much younger than the Earth, an obvious contradiction. Even by the 1990s, some Hubble constant estimates suggested an age for the universe of under 10 billion years, whereas many stars appeared to be several billion years older than that.

Hubble’s original error could be traced to lack of astronomical knowledge. His early overestimates turned out to be signals of a previously unknown distinction between different generations of stars, some younger and some older, Riess pointed out. That threw off distance estimates to some stars that Hubble used to estimate the expansion rate. Similarly, in the 1990s the expansion rate implied too young a universe because dark energy was not then known to exist and therefore was not taken into account when calculating the universe’s age.

So the current discrepancy, Riess suggested, might also be a signal of some astronomical unknown, whether a new particle, new interactions of matter and radiation, or a phenomenon even more surprising — something that would really astound a visitor from another universe.



The X-ray glow keeps growing after the recent neutron star collision


More than 100 days after two neutron stars slammed together, merging into one, new telescope images have revealed that the collision’s lingering X-ray light show has gotten brighter. And scientists don’t fully understand why.

NASA’s orbiting X-ray telescope, Chandra, previously picked up the X-rays 15 days after gravitational waves from the cataclysm reached Earth on August 17, 2017 (SN: 11/11/17, p. 6). The merged remnant then spent several months too close to the sun for its X-rays to be seen.

When the remnant reemerged from the sun’s veil on December 4, it was about four times brighter than when it was last spotted, Daryl Haggard of McGill University in Montreal and her colleagues report January 18 in Astrophysical Journal Letters.

The glow may be tapering off. The XMM-Newton space telescope found on December 29 that the X-ray signal may be starting to weaken, according to a paper published January 18 at arXiv.org.

“The plot is about to thicken,” says Haggard. Chandra has collected new data to look for a drop in brightness.

Scientists are debating how to explain the enduring X-rays. Neutron star collisions are expected to emit bright jets of material, creating X-rays that fade quickly. The long-lasting X-rays might be explained by a “cocoon” of debris (SN Online: 12/20/17), among other possibilities.



Your ultimate fitness guide: welcome to TechRadar’s Fitness Week


Our inaugural Fitness Week has just kicked off on TechRadar where we aim to show you the best tech you should be using to keep fit in 2018 and what the major trends are that will take over the space this year.

We’ve got lots of exciting stuff planned throughout the week, so head back here each day until Sunday to see us everything we’re publishing throughout the week.

Expect fitness diaries using basic trackers to top-end running watches, interviews with some of the biggest health companies on the planet and forward looking features on how we expect tech to progress.


Hunter-gatherer lifestyle could help explain superior ability to ID smells.

Smell has a reputation as a second-rate human sense. But that assumption stinks once hunter-gatherers enter the picture.

Semaq Beri hunter-gatherers, who live in tropical forests on the eastern side of the Malay Peninsula in Southeast Asia, name various odors as easily as they name colors, say psycholinguist Asifa Majid and linguist Nicole Kruspe. Yet Semelai rice farmers, who live in forest outposts near the Semaq Beri and speak a closely related language, find odors much more difficult to name than colors, the researchers report online January 18 in Current Biology.

By including members of a farming community that inhabit a common forest environment and speak a similar language, the new study indicates for the first time that the cultural practices of hunter-gatherers help enhance their odor-naming ability — and possibly their smell-detection skills — relative to settled peoples.

Neuroscientist and odor researcher John McGann of Rutgers University in Piscataway, N.J., calls these results “unexpected and deeply interesting.” Genetics apparently interact with personal experiences of different smells and one’s cultural background to produce odor-naming abilities, McGann says.

Previous research has found that like Semelai farmers, Westerners describe colors far more easily than smells. People in Western societies often talk about odors by resorting to analogies, such as “It smells like banana.”

Semaq Beri hunter-gatherers usually used specific terms for a range of odors as well as colors, say Majid of Radboud University in Nijmegen, the Netherlands, and Kruspe of Lund University in Sweden. These forest dwellers are attuned to odors by virtue of their lifestyle and culture, the investigators propose.

That idea seems likely, since hunter-gatherers spend their lives deploying their sense of smell to hunt and avoid danger, says psychologist and clinical neuroscientist Johan Lundström of the Karolinska Institute in Stockholm. Majid and Kruspe’s study adds to evidence that “the more we use our sense of smell, the better it gets,” he says.

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LOST SMELLS In forests of Southeast Asia’s Malay Peninsula, farmers who live in structures such as these find it harder to name odors than colors, a difficulty neighboring hunter-gatherers don’t share.
Among the Semaq Beri, 18 individuals completed an odor-naming task for the study, and 16 of them also completed a color-naming task. Among the Semelai, 21 participants completed both tasks. Odor participants sniffed marker pens that emitted a total of 16 smells, including orange, leather, rose and fish. On the color task, participants viewed 80 differently hued chips and named 20 of them. Kruspe asked volunteers in their native language either “What smell is this?” or “What color is this?”

Hunter-gatherers used specific terms for odors (such as one translating as “musty”) 86 percent of the time. Colors elicited specific terms (such as a word for “blue”) nearly as often, 80 percent of the time.

In contrast, rice farmers employed specific odor words 56 percent of the time, versus specific color words 78 percent of the time.

Smells carry practical and spiritual importance for the Semaq Beri, Majid says. For instance, foragers must recognize the scent of tiger urine in the forest, a sign that the predatory cats are nearby. Hunters avoid killing certain prey that exude smells associated with pregnancy, so that these animals won’t die out. Semaq Beri religious beliefs hold that certain smells cause illness and others cure ailments. Brothers and sisters are warned not to sit too close together because their smells will mix. “This is considered a sort of incest,” Majid says.

Majid has coauthored previous studies that documented extensive vocabularies for smells in two other Malay Peninsula hunter-gatherer communities as well as among Mexican villagers who, until recently, hunted and gathered but now mix commercial fishing with plant foraging.

“Based on our results, I would predict that other contemporary hunter-gatherers also show better odor naming than non-hunter-gatherers do,” Majid says.

It’s not known whether Semaq Beri individuals display genetic characteristics linked to an especially keen sense of smell or if growing up in a foraging society boosts the activity of genes involved in odor perception.

Researchers need to examine whether childhood exposure to words that specify many odors strengthens hunter-gatherers’ scent-naming skills as adults, Lundström says. Further cross-cultural work should also include tests of sound-naming skills, he says.

Samsung decides to enable FM Radio chips in its smartphones sold in the US


Samsung has just announced a partnership with NextRadio that will see that all its future smartphones will have their FM Radio chips enabled in the United States. LG made a similar move last year for the same reason, so Samsung felt like it needed to even the scales.

According to an official statement, Samsung is the newest smartphone maker that supports NextRadio by unlocking the FM Radio chip in all the upcoming mobile phones in the United States and Canada.

Unfortunately, that probably means the decision doesn’t apply retroactively, so many of the smartphones that are now available in the US will not have their FM Radio chips enabled.

In any case, if you’ll get any of Samsung’s future smartphones that will have their FM Radio chips unlocked, then you will be able to connect directly with the NextRadio app and listen to your favorite local stations.

It will drain less of your battery than streaming radio apps and you won’t need cellular coverage to listen to the radio, so that’s quite an intelligent move from Samsung.

Read more https://www.phonearena.com/news/Samsung-decides-to-enable-FM-Radio-chips-in-its-smartphones-sold-in-the-US_id101533


HMD Global trademarks the Asha brand, new smartphones incoming?


Finnish company HMD Global borrowed the Nokia brand to make smartphones and they’re doing a pretty good job. However, that doesn’t stop HMD from trying to do even better.

It appears that HMD transferred another well-known brand that will probably help it sell even more devices. The “Asha” brand belonged to Nokia before Microsoft acquired the company’s mobile division, but when the Redmond finally bought Nokia’s mobile business, it also got the Asha brand.

Since there’s no official announcement, it’s yet unclear how HMD Global was able to trademark the Asha brand, but the Finnish company must have negotiated the deal with Microsoft.