https://phys.org/news/2017-08-hubble-hi ... anets.html
An international team of astronomers used the NASA/ESA Hubble Space Telescope to estimate whether there might be water on the seven earth-sized planets orbiting the nearby dwarf star TRAPPIST-1. The results suggest that the outer planets of the system might still harbour substantial amounts of water. This includes the three planets within the habitable zone of the star, lending further weight to the possibility that they may indeed be habitable.
On 22 February 2017 astronomers announced the discovery of seven Earth-sized planets orbiting the ultracool dwarf star TRAPPIST-1, 40 light-years away. This makes TRAPPIST-1 the planetary system with the largest number of Earth-sized planets discovered so far.
Following up on the discovery, an international team of scientists led by the Swiss astronomer Vincent Bourrier from the Observatoire de l'Université de Genève, used the Space Telescope Imaging Spectrograph (STIS) on the NASA/ESA Hubble Space Telescope to study the amount of ultraviolet radiation received by the individual planets of the system. "Ultraviolet radiation is an important factor in the atmospheric evolution of planets," explains Bourrier. "As in our own atmosphere, where ultraviolet sunlight breaks molecules apart, ultraviolet starlight can break water vapour in the atmospheres of exoplanets into hydrogen and oxygen."
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Human antidepressants are building up in the brains of bass, walleye and several other fish common to the Great Lakes region, scientists say.
In a new study, researchers detected high concentrations of these drugs and their metabolized remnants in the brain tissue of 10 fish species found in the Niagara River.
This vital conduit connects two of the Great Lakes, Lake Erie and Lake Ontario, via Niagara Falls. The discovery of antidepressants in aquatic life in the river raises serious environmental concerns, says lead scientist Diana Aga, PhD, the Henry M. Woodburn Professor of Chemistry in the University at Buffalo College of Arts and Sciences.
"These active ingredients from antidepressants, which are coming out from wastewater treatment plants, are accumulating in fish brains," Aga says. "It is a threat to biodiversity, and we should be very concerned.
"These drugs could affect fish behavior. We didn't look at behavior in our study, but other research teams have shown that antidepressants can affect the feeding behavior of fish or their survival instincts. Some fish won't acknowledge the presence of predators as much."
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A long-standing but unproven assumption about the X-ray spectra of black holes in space has been contradicted by hands-on experiments performed at Sandia National Laboratories' Z machine.
Z, the most energetic laboratory X-ray source on Earth, can duplicate the X-rays surrounding black holes that otherwise can be watched only from a great distance and then theorized about.
"Of course, emission directly from black holes cannot be observed," said Sandia researcher and lead author Guillaume Loisel, lead author for a paper on the experimental results, published in August in Physical Review Letters. "We see emission from surrounding matter just before it is consumed by the black hole. This surrounding matter is forced into the shape of a disk, called an accretion disk."
The results suggest revisions are needed to models previously used to interpret emissions from matter just before it is consumed by black holes, and also the related rate of growth of mass within the black holes. A black hole is a region of outer space from which no material and no radiation (that is, X-rays, visible light, and so on) can escape because the gravitational field of the black hole is so intense.
"Our research suggests it will be necessary to rework many scientific papers published over the last 20 years," Loisel said. "Our results challenge models used to infer how fast black holes swallow matter from their companion star. We are optimistic that astrophysicists will implement whatever changes are found to be needed."
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Soon after the Big Bang, the universe went completely dark. The intense, seminal event that created the cosmos churned up so much hot, thick gas that light was completely trapped. Much later—perhaps as many as one billion years after the Big Bang—the universe expanded, became more transparent, and eventually filled up with galaxies, planets, stars, and other objects that give off visible light. That's the universe we know today.
How it emerged from the cosmic dark ages to a clearer, light-filled state remains a mystery.
In a new study, researchers at the University of Iowa offer a theory of how that happened. They think black holes that dwell in the center of galaxies fling out matter so violently that the ejected material pierces its cloudy surroundings, allowing light to escape. The researchers arrived at their theory after observing a nearby galaxy from which ultraviolet light is escaping.
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