Space Science

Astronomers catch two giant galaxies merging in images from Europe's Herschel space telescope - The Verge. #space

A study notes "a lot of excitement and interest from various companies" for such ventures.

“Because dark energy makes up about 70 percent of the content of the universe, it dominates over the matter content. That means dark energy will govern expansion and, ultimately, determine the fate of the universe.” -Eric Linder It’s been a while since we’ve spoken about dark energy, and we were just talking about Einstein’s greatest blunder, so let’s just dive right in. Image credit: S. Beckwith & the HUDF Working Group (STScI), HST, ESA, NASA. This is our observable Universe, as unveiled by the Hubble Space Telescope. With hundreds of billions of galaxies stretched out some 41 billion light years in all directions, finding out about what our Universe was like in the distant past, the recent past, and what it’s like today is limited only by our willingness to look. In particular, there are three great sets of observations that tell us ever so much about the Universe on the largest scales. Image credit: Northern Galactic Cap from the SDSS-III release, via http://www.sdss3.org/. 1.) The way galaxies cluster together on the largest scales. By looking at huge, tremendous surveys of galaxies, we can see how the visible matter in the Universe has clustered, clumped, and grouped together, as well as where it hasn’t, and has left us great cosmic voids. By putting various ingredients into a model Universe governed by General Relativity, we can also simulate how structure should form in our Universe. Where the simulations and the observations match up, that tells us what’s in our Universe. Image credit: ESA and the Planck Collaboration. 2.) The temperature fluctuations in the cosmic microwave background. By looking at the temperature fluctuations — the hot-and-cold spots — in the CMB, we can know what the Universe looked like in terms of overdensities, underdensities, and how they’re clustered with respect to one another all the way back at a time when the Universe was just some 380,000 years old! Because the light has had to travel for nearly the entire 13.8 billion years that the Universe has been around (it’s been traveling for 99.997% of the Universe’s history), we can find out information about what the Universe was like back then, but also how it’s expanded since then. This pattern of fluctuations also tells us what the various combinations of ingredients are in our Universe. Image credit: Kowalski et al., Ap.J., 2008. 3.) Direct observations of well-understood objects at various distances/redshifts in the Universe. Everything from variable stars to properties of galaxies to distant supernovae help us get a handle on this, the cosmic distance ladder. This tells us how the Universe has been expanding since as far back as we can measure until the present day. When these three data sets are combined — and we can combine others, too, but these three are the best data sets we have — they tell us that there’s matter in the Universe, about 31-32% of the Universe is matter (most of which is dark matter), and that there’s another type of energy, dark energy, that makes up the rest. Image credit: Planck Collaboration: P. A. R. Ade et al., 2013, A&A Preprint; annotations by me. So, you ask, just what is dark energy, and how do we know? In principle — and by in principle, I mean in General Relativity — matter, energy, topological defects, and pretty much anything else that you throw into your Universe is going to affect how your Universe expands because of two properties inherent to it: it’s energy density and its pressure. Image credit: Large Synoptic Survey Telescope, NSF, DOE, and AURA. Because of the way the Universe is observed to expand, and because of the known way that matter (yes, even dark matter, according to General Relativity) behaves, we can infer something about the energy density and pressure of dark energy. In particular, we know that dark energy’s pressure is negative, and that it’s quite negat

A once-prominent swimming coach who trained thousands of children was sentenced to seven years in prison Thursday for sexually abusing one of the girls he instructed.

An 87-year-old grandmother took on billionaire Donald Trump. And on Thursday, she lost.

Because of the deadlock, the judge ordered a retrial in the penalty phase.

Shoppers in the U.S. will soon have more information about where their meat comes from after new federal labeling rules went into effect Thursday. The rules require labels on steaks, ribs and other cuts ...

               The iconic  Ring Nebula's distinctive shape makes it a popular illustration for astronomy books. But new observations by NASA's Hubble Space Telescope of the glowing gas shroud around an old, dying, sun-like star shown below reveals a new twist. "The nebula is not like a bagel (NRAO radio image above), but rather, it's like a jelly doughnut, because it's filled with material in the middle," said C. Robert O'Dell of Vanderbilt University in Nashville, Tenn. He leads a research team that used Hubble and several ground-based telescopes to obtain the best view yet of the iconic nebula. The images show a more complex structure than astronomers once thought and have allowed them to construct the most precise 3-D model of the nebula. "With Hubble's detail, we see a completely different shape than what's been thought about historically for this classic nebula," O'Dell said. "The new Hubble observations show the nebula in much clearer detail, and we see things are not as simple as we previously thought."                The Ring Nebula is about 2,000 light-years from Earth and measures roughly 1 light-year across. Located in the constellation Lyra, the nebula is a popular target for amateur astronomers. Previous observations by several telescopes had detected the gaseous material in the ring's central region. But the new view by Hubble's sharp-eyed Wide Field Camera 3 shows the nebula's structure in more detail. O'Dell's team suggests the ring wraps around a blue, football-shaped structure. Each end of the structure protrudes out of opposite sides of the ring. The nebula is tilted toward Earth so that astronomers see the ring face-on. In the Hubble image, the blue structure is the glow of helium. Radiation from the white dwarf star, the white dot in the center of the ring, is exciting the helium to glow. The white dwarf is the stellar remnant of a sun-like star that has exhausted its hydrogen fuel and has shed its outer layers of gas to gravitationally collapse to a compact object. O'Dell's team was surprised at the detailed Hubble views of the dark, irregular knots of dense gas embedded along the inner rim of the ring, which look like spokes in a bicycle wheel. These gaseous tentacles formed when expanding hot gas pushed into cool gas ejected previously by the doomed star. The knots are more resistant to erosion by the wave of ultraviolet light unleashed by the star. The Hubble images have allowed the team to match up the knots with the spikes of light around the bright, main ring, which are a shadow effect. Astronomers have found similar knots in other planetary nebulae. All of this gas was expelled by the central star about 4,000 years ago. The original star was several times more massive than our sun. After billions of years converting hydrogen to helium in its core, the star began to run out of fuel. It then ballooned in size, becoming a red giant. During this phase, the star shed its outer gaseous layers into space and began to collapse as fusion reactions began to die out. A gusher of ultraviolet light from the dying star energized the gas, making it glow. The outer rings were formed when faster-moving gas slammed into slower-moving material. The nebula is expanding at more than 43,000 miles an hour, but the center is moving faster than the expansion of the main ring. O'Dell's team measured the nebula's expansion by comparing the new Hubble observations with Hubble studies made in 1998. The Ring Nebula will continue to expand for another 10,000 years, a short phase in the lifetime of the star. The nebula will become fainter and fainter until it merges with the interstellar medium. Studying the Ring Nebula's fate will provide insight into the sun's demise in another 6 billion years. The sun is less massive than the Ring Nebula's progenitor star, so it will not have an opulent ending. "Whe

Illustrated London NewsStarving people searching for potatoes in a stubble field during the Great Famine (1845-1852) which was caused by the failure of the Irish potato crop and British government inaction.By Alan Boyle, Science Editor, NBC NewsScientists have finally figured out exactly what strain of potato blight led to the deaths of more than a million people in Ireland during the Great Famine of the mid-19th century — and it's not the usual suspect.For decades, researchers assumed that a particular strain of Phytophthora infestans, known as US-1, made the leap from the Americas to mainland Europe, and then to Ireland in the 1840s. Selective breeding and fungicides have made US-1 less of a threat than it was a century and a half ago, but it and other strains of blight continue to pose a threat to potato crops around the world. Blight can still turn seemingly healthy potatoes into black, stinking balls of mush, just as it did in 19th-century Ireland.An international team of scientists took on the task of tracing the roots of late blight through genetics, and to flesh out the story, they deciphered the genomes for 11 strains of blight preserved in Germany's Bavarian State Collection for Botany and London's Kew Gardens. The dried potato plants containing the blight pathogens were saved in herbaria — that is, collections of preserved plants — by 19th-century scientists who had no idea they could yield that kind of scientific data.What the researchers found surprised them: The genetic signature of the blight that was extracted from the Irish potato plants did not match up exactly with US-1. Instead, the blight represented a closely related but previously unknown strain that has now been designated HERB-1.The study of blight evolution is to be published in the open-access journal eLife.Roots of the blightBy mapping the genetic differences between the 19th-century samples and 15 modern-day strains of blight, the scientists could reconstruct the pathogen's evolution over the centuries. They determined that the blight originated in Mexico's Toluca Valley. The species' genetic diversity increased markedly in the 16th century, around the time that Spanish explorers settled the New World. That era marked the wider spread of potato varieties, and probably hastened the evolution of Phytophthora infestans as well.Kew GardensThis potato specimen from the Kew Gardens' herbarium was collected in 1847, during the height of the Irish famine. The legend reads "Botrytis infestans" because it was not known yet that Phytophthora does not belong to the mildew-causing Botrytis fungi.The similarities between US-1 and HERB-1 suggest that they both made their appearance in the early 19th century, not long before the first major outbreak of the blight in Europe. "Probably they both came out of the United States," said one of the study's authors, Sophien Kamoun, a researcher at the Sainsbury Laboratory in Britain.HERB-1 spread to Europe first, and soon made its way to Ireland, where potatoes were the staple crop for millions of poor farmers. "The potatoes at the time were very susceptible to blight," Kamoun told NBC News. More than a million people died between 1845 and 1852, and at least that many emigrated to friendlier locales. Even today, Ireland's population level has not returned to the pre-famine high of 8 million.US-1's rise came in the 20th century, after the introduction of new potato varieties that were resistant to HERB-1. Eventually, US-1 became the dominant blight strain, and HERB-1 faded away. "We think HERB-1 is most likely extinct," Kamoun said.Delving into DNAThe research illustrates how useful herbaria can be for resolving decades-old questions about centuries-old plants. "The degree of DNA preservation in the herbarium samples really surprised us," Johannes Krause of the University of Tübingen said in a news release about the study. It also illustrates how quickly evolution can produce new strains of pathogens,

Three astronauts talked about science, social media and sandwiches during the live video conference.