During an August 20 event at NASA headquarters, called Ancient Earth, Alien Earths, a panel of scientists from NASA and other organizations discussed how vastly different and inhospitable we all would find ancient Earth, if we could go back in time. Despite the conditions, though, it was an environment in which life began and evolved – and understanding how that was possible could help us recognize habitable planets around other stars.
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Scientists continue to investigate the development of self-replicating, intricate sets of chemistry — in other words, life — from the chemical compounds thought available on early Earth. Out of this mixture of prebiotic chemicals, two nucleic acids — RNA and DNA — emerged as champions. Astrobiologists want to understand the origin of DNA and its genetic cousin, RNA, because figuring out how life got started here on Earth is key for gauging if it might ever develop on alien planets. New research intriguingly suggests that DNA, the genetic information carrier for humans and other complex life, might have had a rather humbler origin. In some microbes, a study shows, DNA pulls double duty as a storage site for phosphate. This all-important biomolecule contains phosphorus, a sometimes hard-to-get nutrient.
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Massive stars end their life with a bang, exploding as supernovas and releasing massive amounts of energy and matter. What remains of the star is a small and extremely dense remnant: a neutron star or a black hole. Neutron stars come in several flavours, depending on properties such as their ages, the strength of the magnetic field concealed beneath their surface, or the presence of other stars nearby. Some of the energetic processes taking place around neutron stars can be explored with X-ray telescopes, like ESA's XMM-Newton.
Continue reading "Image of the Day: "The Blue Monster" --Rare Million-Year-Old Neutron Star Discovered Near a Recent Supernova" »
Only one species of the billions of species that have existed on Earth has shown an aptitude for radios and even we failed to build one during the first 99% of our 7 million year history. Charley Lineweaver, a provocative cosmologist with The Australian National University, believes the "Planet of the Apes Hypothesis" -a theory subscribed to by Carl Sagan and the astronomers involved with the Search for Extraterrestrial Intelligence (SETI), that human-like intelligence is a convergent feature of evolution -that there is an intelligence niche, into which other species will evolve if the human species goes extinct is based on a flawed notion of evolution, a notion that could have serious implications for our search for intelligent life elsewhere in the Milky Way Galaxy.
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"Fundamentally, the solar system and everything in it was ultimately derived from a cloud of interstellar gas and dust," says Andrew Westphal, physicist at the University of California, Berkeley's Space Sciences Laboratory and lead author on the paper published this week in Science titled "Evidence for interstellar origin of seven dust particles collected by the Stardust spacecraft". "We're looking at material that's very similar to what made our solar system."
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It may sound like science fiction, but astronomers have worked out a scheme that will allow them to detect and measure particles ten times smaller than the width of a human hair, even at many light-years distance. They can do this by observing a blue tint in the light from far-off objects caused by the way in which small particles, no more than a micron in size (one-thousandth of a millimeter) scatter light.
Continue reading ""Detecting Alien Planet Particles Smaller than a Human Hair" --New SETI Breakthrough" »
Astrophysicists obtained for the first time spectra of radiating cobalt registered at the supernova SN2014J, shown above, located 11 million light-years from Earth. Isotope 56Co has a half-life of just 77 days, and does not exist in normal conditions. However, during a giant thermonuclear explosion of a supernova, this short-lived radioactive isotope is produced in large quantities. The reason was the rarity of explosions at such a distance – 11 million light-years is a large value on the galactic scale (the diameter of a galaxy is about 100,000 light-years, the distance between stars is a few light-years), but on an intergalactic scale it is a relatively short distance. There are several hundreds of galaxies within a radius of ten million light-years; supernovae produce explosions like this (type Ia explosions) once every few centuries in a galaxy, including a type Ia supernova that exploded in the Milky Way in 1606.
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Astronomers using the National Science Foundation’s (NSF) Green Bank Telescope (GBT) have discovered that filaments of star-forming gas near the Orion Nebula may be brimming with pebble-size particles -- planetary building blocks 100 to 1,000 times larger than the dust grains typically found around protostars. If confirmed, these dense ribbons of rocky material may well represent a new, mid-size class of interstellar particles that could help jump-start planet formation.
Continue reading "Vast Streams of Gravel Detected in Orion Molecular Cloud -- "A Long and Winding Road in Space Essential for Planet Formation"" »
A fully developed elliptical galaxy is a gas-deficient gathering of ancient stars theorized to develop from the inside out, with a compact core marking its beginnings. Astronomers have for the first time caught a glimpse of the earliest stages of massive galaxy construction. The building site is a dense galactic core blazing with the light of millions of newborn stars that are forming at a ferocious rate.
Continue reading "First Ever Observation of an Emerging Ancient Elliptical Galaxy --"Twice as Many Stars as Milky Way in a Region Only 6,000 Light Years Across"" »
Quasars are the brightest objects in the Universe; their intense light is generated by gas as it falls towards a black hole. These mysterious objects emitting radio waves were first identified in 1963 by radio astronomers who called them quasi-stellar radio sources, or quasars. Galaxies can contain millions or billions of stars, but are still dim by comparison. Understanding whether the numerous small galaxies outshine the rare, bright quasars will provide insight into the way the universe built up today’s populations of stars and planets. It will also help scientists properly calibrate their measurements of dark energy, the agent thought to be accelerating the universe’s expansion and determining its far future.
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Today's Most Popular..."Most of the universe consists of hydrogen in various forms," said Ludwik Adamowicz, a professor in the University of Arizona''s department of chemistry and biochemistry, but the H3+ ion is the most prevalent molecular ion in interstellar space. It's also one of the most important molecules in existence." Believed to be critical to the formation of stars in the early days of the universe, H3+ also is the precursor to many types of chemical reactions, said Adamowicz, including those leading to compounds such as water or carbon, which are essential for life.
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“We want to find out whether spacetime is a quantum system just like matter is,” said Craig Hogan, director of Fermilab’s Center for Particle Astrophysics and the developer of the holographic noise theory. “If we see something, it will completely change ideas about space we’ve used for thousands of years.”
Continue reading "Is Our 3-D Universe an Illusion? --"Everything Could Actually be Encoded in Tiny packets in Two Dimensions"" »
When the universe was less than one microsecond old and more than one trillion degrees, it transformed from a plasma of quarks and gluons into bound states of quarks - also known as protons and neutrons, the fundamental building blocks of ordinary matter that make up most of the visible universe.
Continue reading ""When the Visible Universe was Less than One Microsecond Old" --Researchers Simulate Birth of the Cosmos" »
There may be a suite of organic chemical reactions occurring in interstellar space that astronomers hadn't considered. In 2012, astronomers discovered methoxy molecules containing carbon, hydrogen and oxygen in the Perseus molecular cloud, around 600 light years from Earth. But researchers were unable to reproduce this molecule in the lab by allowing reactants to condense on dust grains, leaving a mystery as to how it could have formed.
Continue reading "Interstellar Space is a 'Quantum-Weirdness' Lab --"Organic Reactions Occurring that Shouldn't Exist"" »
Luckily for researchers, there is a possible laboratory in our solar system to help us better understand the conditions on Earth before life arose — a situation sometimes referred to as a “prebiotic” environment. That location is Titan, the largest moon of Saturn, that has fascinated researchers for decades, particularly after NASA’s Voyager 1 and Voyager 2 spacecraft flew by Saturn in the 1980s. The missions revealed a moon completely socked in with haze, which is a different experience to those used to gazing at Earth’s airless, cratered moon.
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Unravelling the mysteries of magnetic fields is crucial to understanding how our Universe works. For too long, many of the big questions about magnetic fields have simply been untestable before this new era of radio astronomy. "This opens a new window to the Universe where we do not know what galaxies will look like", observes Rainer Beck, lead astronomer with the Max Planck Institute. "Maybe we will see how galaxies are magnetically connected to intergalactic space. This is a key experiment in preparation for the planned Square Kilometre Array (SKA) that should tell us how cosmic magnetic fields are generated."
Continue reading ""The Invisible Galaxies" --Radio Images of the Whirlpool Galaxy & Beyond" »
"It's very exciting to think that the dwarf planets could have astrobiological potential," says New Horizons lead scientist Alan Stern of the Southwest Research Institute. In 2011, the highly sensitive Cosmic Origins Spectrograph aboard the Hubble Space Telescope discovered a strong ultraviolet-wavelength absorber on Pluto's surface, providing new evidence that points to the possibility of complex hydrocarbon and/or nitrile molecules lying on the surface, according to researchers from Southwest Research Institute and Nebraska Wesleyan University. These chemical species can be produced by the interaction of sunlight or cosmic rays with Pluto's known surface ices, including methane, carbon monoxide and nitrogen.
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The first breakthrough paper to come out of a massive U.S. expedition to one of Earth’s final frontiers shows that there’s life and an active ecosystem one-half mile below the surface of the West Antarctic Ice Sheet, specifically in a lake that hasn’t seen sunlight or felt a breath of wind for millions of years. “We are looking at a water column that probably has about 4,000 things we call species. It’s incredibly diverse,” said Brent Christner, associate professor of biological sciences at Louisiana State University.
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Composite view showing Neptune on Triton's horizon. Neptune's south pole is to the left; clearly visible in the planets' southern hemisphere is a Great Dark Spot, a large anticyclonic storm system located about 20 degrees South. The foreground is a computer generated view of Triton's maria as they would appear from a point approximately 45 km above the surface. The terraces visible in this image indicate multiple episodes of 'cryovolcanic' flooding. This three-dimensional view was created from a Voyager image by using a two-dimensional photoclinometric model. Relief has been exaggerated roughly 30-fold, the actual range of the relief is about 1 km.
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Superlatives are the trademark of the planet Jupiter. The magnetic field at the top edge of the cloud surrounding the largest member of the solar system is around ten times stronger than Earth’s, and is by far the largest magnetosphere around a planet in our Solar System. Just why this field has a similar structure to that of our own planet although the interiors of the two celestial objects have a completely different structure, has mystified researchers for a long time.
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Four previously unknown galaxy clusters each potentially containing thousands of individual galaxies have been discovered some 10 billion light years from Earth. Most clusters in the universe today are dominated by giant elliptical galaxies in which the dust and gas has already been formed into stars. "What we believe we are seeing in these distant clusters are giant elliptical galaxies in the process of being formed," says David Clements, from the Department of Physics at Imperial College London.
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NGC 3603 is a very bright star cluster and is famed for having the highest concentration of massive stars that have been discovered in our galaxy so far. At the centre lies a Wolf–Rayet multiple star system, known as HD 97950. Wolf–Rayet stars are at an advanced stage of stellar evolution, and start off with around 20 times the mass of the Sun. But, despite this large mass, Wolf–Rayet stars shed a considerable amount of their matter due to intense stellar winds , which blast the star's surface material off into space at several million kilometres per hour, a crash diet of cosmic proportions.
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It came as something of a surprise when Center for Astrophysics astronomers and their colleagues discovered a faint line corresponding to no known element. Esra Bulbul, Adam Foster, Randall Smith, Scott Randall and their team were studying the averaged X-ray spectrum of a set of seventy-three clusters (including Virgo above) looking for emission lines too faint to be seen in any single one when they uncovered a line with no known match in a particular spectral interval not expected to have any features.
Continue reading "Harvard Astronomers Study Mystery Signal from No Known Element --"Is it the Long-Sought Dark Matter Particle?"" »
The universe has so many black holes that it’s impossible to count them all. There may be 100 million of these intriguing astral objects in our galaxy alone. Nearly all black holes fall into one of two classes: big, and colossal. Astronomers know that black holes ranging from about 10 times to 100 times the mass of our sun are the remnants of dying stars, and that supermassive black holes, more than a million times the mass of the sun, inhabit the centers of most galaxies.
Continue reading ""Music of Black Holes" --Astronomers Observe a Rhythmic Pattern of Light Pulses" »
How might humanity prepare for the possibility of discovering microbial or complex life beyond Earth? Scientists, historians, philosophers and theologians from around the world will convene at the Library of Congress John W. Kluge Center for two days in September to discuss: “Preparing for Discovery: A Rational Approach to the Impact of Finding Microbial, Complex or Intelligent Life Beyond Earth."
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Fedor Bezrukov from the RIKEN–BNL Research Center and Mikhail Shaposhnikov from the Swiss Federal Institute of Technology in Lausanne propose that the Higgs boson, which was recently confirmed to be the origin of mass, may also be responsible for the mode of inflation and shape of the Universe shortly after the Big Bang. “There is an intriguing connection between the world explored in particle accelerators today and the earliest moments of the existence of the Universe,” explains Bezrukov.
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The worst mass extinction the Earth has ever seen occurred 252 million years ago. The boundary of the Permian and Triassic geological periods marked the demise of around 90 percent of marine species and 70 percent of land species. Solving the intricate puzzles of mass extinctions is vital when it comes to understanding the external factors that could hinder life on other planets. Several theories have been proposed to explain this mass extinction, but scientists believe that the most likely trigger for this mass extinction was one of the largest volcanic eruptions ever recorded.
Continue reading "Marine Fossils Offer New Clues to Cause of the "Great Dying" Extinction Event" »
NASA's Stardust Mission team reports that they have found seven dust motes that probably came from outside our solar system, perhaps created in a supernova explosion millions of years ago and altered by eons of exposure to the extremes of space. They would be the first confirmed samples of contemporary interstellar dust.
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Scientists think that a giant asteroid, which broke up long ago in the main asteroid belt between Mars and Jupiter, eventually made its way to Earth and led to the extinction of the dinosaurs. Following the February 2013 asteroid impact in Chelyabinsk, Russia, there is renewed interest in figuring out how to deal with the potential hazard of an asteroid impact. Understanding what keeps asteroids intact can aid strategies to guard against future impacts that could destroy life as we know it.
Continue reading "Saving the Planet --Forces that Hold Gravity-Defying Asteroids Together Discovered" »