When members of the Yao tribe in Mozambique set off to search for wild honey, they don’t go alone.
To find hidden bee hives, the tribesmen enlist the help of expert guides, birds native to the African savanna appropriately named “honeyguides” (Indicator indicator). At the outset of a hunt, the Yao will call out with a distinctive vocalization consisting of a sustained trill followed by an emphatic grunt, best described as a “brrr-hm” sound.
If they’re lucky, one of the small, brown birds will show up and flit from tree to tree, chattering all the while, guiding the hunters toward their sweet target. And in this partnership, humans and birds both leave happy. Read More
If someone proposed a “death tax”, how likely would you be to vote for it? What if we called it an “estate tax”?
The words used to frame arguments can play an important role in shaping opinions of important issues — “death” and “estate” can yield two different interpretations of the same concept. That the kinds of words we use to build an argument is important has long been known, but a new study led by a researcher at Stanford University suggests that politicians are playing word games at an unprecedented level — and a specific moment in history is marked as the watershed moment of this shift. Read More
TRAPPIST-1 may well be one of the closest stars to look for life in our own backyard, thanks to three planets in its habitable zone.
Now, we’re one step closer to understanding if those planets could hold life, thanks to a new study published today in Nature.
Using data gathered from the Hubble Space Telescope, researchers at MIT witnessed two occultation events from the innermost planets, TRAPPIST-1b and 1c. The two had near-simultaneous transit events on May 4, 2016 just 12 minutes apart, and some spectrum was gathered from the transit.
Through this, the MIT team made the first atmospheric observation of an Earth-mass planet, and determined the atmosphere of both planets lacked a “gas envelope” of hydrogen and helium around them.
That means that the planets don’t belong to a strange class of planets called gas dwarfs, which is exactly what it sounds like: a mini-mini-Jupiter. They often are terrestrial planets enveloped in a thick atmosphere with a similar composition to Saturn or Jupiter.
“If they were to have such an atmosphere, then they would not be habitable,” says Julien de Wit, lead author of the study and an MIT postdoc. He coauthored the paper announcing the initial discovery of TRAPPIST-1’s system in a May Nature paper.
By ruling out the gas dwarf scenario, the researchers can now home in on more specific details of these two planets. This includes determining if they have atmospheres that are dense and Venus-like or filled with water vapor, which would place them as more Earth-like. There’s also the possibility that, like Mercury, the planets lack anything more than an incredibly thin exosphere.
Some of the really detailed observations of the system, which is is just 39 light years away from Earth, will have to wait for the 2018 launch of the James Webb Space Telescope, which will characterize the atmospheres of Earth-like planets in detail.
In the meantime, de Wit and colleagues will have to rely on data from Hubble, which can still be used to to determine key characteristics like the presence of water or methane. While they might not get as lucky as a two-for-one transit next time, it still could reveal if TRAPPIST-1’s planets contain the ingredients for life.
“What occurred on May 4 was a very rare event,” says de Wit.
This article originally appeared on Astronomy.com.
The human eye is sensitive enough pick out a single photon of light in otherwise complete darkness.
Light-sensitive cells called rods, located in the back of your eye, can react to single photons, but that’s not the same as actually seeing the light. Sight, in the way that we think of consciously perceiving a visual, requires the retina and the brain to process those signals. For decades, researchers have wondered how little light the human eye could actually detect. Now, it turns out that one photon – the smallest unit of light — is enough to send a signal to the brain. Read More
Scientists from the Centers for Disease Control and Prevention (CDC) are scrambling to figure out how a Utah caregiver became ill with Zika.
The virus is overwhelmingly transmitted via bites from infected mosquitoes, but can also spread through sexual contact. The case in Utah seems to be the result of something completely different, however, say state officials. Scientists aren’t exactly sure how the person became infected, but they working to figure what’s behind this latest twist in the ongoing epidemic.
While millions of people are out hunting Pokémon, biologists are conducting an equally fervent hunt for new and rare species. And instead of 151 species, they estimate that they need to find another 4,000 or so before they become the very best.
A new study builds a compendium of all the tree species collected from the Amazon over past three centuries, and concludes that we won’t find them all until 2316. In total, researchers from the Field Museum say researchers have, so far, collected 11,676 unique tree species from the Amazon rainforest, and that there are likely some 16,000 there in total, based on recent projections. Read More
In the quest for dark energy, astronomers have created an unprecedented 3-D map of galaxies in a volume of about 650 cubic billion light years.
Hundreds of astronomers from the Sloan Digital Sky Survey III (SDSS-III) and the Max Planck Institutes for Extraterrestrial Physics (MPE) and for Astrophysics (MPA) contributed to this map. The astronomers found that the map agrees with the current cosmological model (the Lambda Cold Dark Matter model) and confirmed that dark energy is a cosmological constant.
Understanding how dark energy interacts and affects our universe is crucial to unraveling how the universe came to be and how it may end. Dark energy is believed to be what contradicts the force of gravity and is what is accelerating the expansion of the universe. These findings were submitted to the Monthly Notices of the Royal Astronomical Society (MNRAS) as a collection of papers.
“We have spent a decade collecting measurements of 1.2 million galaxies over one quarter of the sky to map out the structure of the universe over a volume of 650 cubic billion light-years,” says Dr. Jeremy Tinker of New York University in a press release.
The Baryon Oscillation Spectroscopic Survey (BOSS) of the SDSS-III carried out the precise measurements found. By studying the tugs between dark energy and dark matter, the scientists were able to determine the Baryonic Acoustic Oscillation (BAO) between the galaxies in the map to measure the expansion rate of the universe.
The normal BAO size is found from pressure waves that traveled throughout the universe when it was only 400,000 years old (the universe is currently 13.8 billion years old). The distribution of matter throughout the galaxy represents a frozen image of the life of these waves. All galaxies are therefore separated preferentially by a characteristic distance in what is called the BAO scale.
Using observations from the cosmic microwave background (CMB), the size of the acoustic scale at the universe’s current age can be determined. This is because the light that is emitted corresponds to when the pressure waves became frozen. Seeing how the distribution of galaxies has changed since then can give astronomers clues to how dark energy and dark matter have battled over the expansion rate of the universe. Ariel Sanchez, from MPE, was the astronomer who led the search to find the total amounts of dark energy and dark matter in the universe.
“Measuring the acoustic scale across cosmic history gives a direct ruler with which to measure the universe’s expansion rate,” says Sanchez in the same press release. “ With BOSS, we have traced the BAO’s subtle imprint on the distribution of galaxies spanning a range of time from 2 to 7 billion years ago.”
These very precise measurements had to be analyzed many times, in particular the distances from Earth to the galaxies in the map. Using a spectrometer, the light from a galaxy appears red-shifted as it is moving away from us. The red-shift in light is how the astronomers were able to correlate the galaxy’s distance from Earth; the farther a galaxy is, the faster it moves and therefore the more it is red-shifted. Dr. Shun Saito from MPA contributed models to the BOSS data analysis.
“However, galaxies also have peculiar motions and the peculiar velocity component along the line-of-sight leads to the so-called redshift space distortion,” says Saito in the same press release. “This makes the galaxy distribution anisotropic because the line-of-sight direction is now special — only along this direction the distance is measured through a redshift, which is contaminated by peculiar velocity. In other words, the characteristic anisotropic pattern allows us to measure the peculiar velocity of galaxies — and because the motion of galaxies is governed by gravity, we can use this measurement to constrain to what level Einstein’s general relativity is correct at cosmological scales. In order to properly interpret the data, we have developed a refined model to describe the galaxy distribution.”
Another possible approach is to use the angular positions of the galaxies in the sky rather than the 3-D physical positions in the universe.
“This method uses only observables,” says Dr. Salvador Salazar, a junior MPE researcher, in the same press release. “We make no prior assumptions about the cosmological model.”
Many approaches have been used to try and analyze the huge BOSS data set. “We now have seven measurements, which are slightly different, but highly correlated,” Sanchez says in a separate press release. “To extract the most information about the cosmological parameters, we had to find not only the best methods and models for data analysis but also the optimal combination of these measurements.”
Their strenuous efforts have paid off as the BOSS data show that dark energy is causing the expansion of the universe with an error of only 5 percent in the cosmological constant found. The cosmological constant is called Lambda, as coined by Albert Einstein as a repellant effect in the universe. These findings are still consistent with the relatively young theory of the cosmological model.
The map also reveals that galaxies tend to move to areas with more matter, staying true to the laws of gravity as well as the infall of material following the laws of general relativity. This suggests that the idea of the expansion of the universe is caused by a phenomenon like dark energy that works on large cosmic scales and dismisses the notion that our laws of gravity are breaking down.
This post originally appeared on Astronomy.com.
The struggle between humans and viruses stretches back far into the dusty depths of history, and it appears that we wear the scars of this epic battle in that most personal of places: our genome.
Whenever a viral epidemic tears through a community, there are those lucky enough to possess mutations rendering them immune to the disease. If the epidemic is large enough, this mutation can become embedded in our genome, both because of its protective powers, and because those with it will be overrepresented in the surviving population.
Many of the genetic alterations wrought by viruses ares still present in our genome today, and in a new paper, researchers at Stanford University suggests that as much as 30 percent of the adaptions seen in our proteins since the split with chimpanzees millions of years ago could be a direct result of viral infections. Read More
When you step off a plane in another country, the first thing you usually want to do is hit the hay. It’s the sleepy side effect of travel known as jet lag.
Experienced travelers power through fatigue and wait until nighttime to get some shut-eye in an attempt to match the natural cycles of their new locale. While some people acclimate to time-zone jumping better than others, most agree that traveling eastward is a more daunting challenge to our sleep cycle, but it’s not clear why that is. Read More
On July 4, space enthusiasts awaited word that the Juno probe had entered orbit around Jupiter. The journey was perilous, as the craft was going incredibly fast. Once that was done, it turned its solar panels towards the sun and began its first orbit. Now, a safe distance from Jupiter has been attained and the system is slowly coming online, giving NASA its first photo opportunity since it made its own jovian fireworks. Read More