Excerpt from huffingtonpost.comIntroduction 65 years ago, in 1950, while having lunch with colleagues Edward Teller and Herbert York, Nobel physicist Enrico Fermi suddenly blurted out, "Where is everybody?" His question is now known as Fermi's p...
Tag: the Universe (page 4 of 18)
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| Pulsars are types of neutron stars; the dead relics of massive stars. What sets pulsars apart from regular neutron stars is that they’re highly magnetized, and rotating at enormous speeds. |
Excerpt from uncovercalifornia.com
A Pulsar with the widest orbit around a neutron star has been discovered by a team of high school students and the discovery has been confirmed by astronomers. High School students from many states who participated in NSF-funded educational outreach program have found the pulsar after analyzing data from Robert C. Byrd Green Bank Telescope (GBT).
In a research paper accepted by the Astrophysical Journal, lead author Joe Swiggum, a graduate student in physics and astronomy at West Virginia University in Morgantown, said, “Pulsars are some of the most extreme objects in the universe. The students' discovery shows one of these objects in a really unique set of circumstances.”
The object has been codenamed PSR J1930-1852 by astronomers. It was discovered in 2012 by Cecilia McGough from Strasburg High School in Virginia and De'Shang Ray from Paul Laurence Dunbar High School in Baltimore, Maryland.
The discovery of a pulsar with extra wide orbit could help in understanding the concepts behind binary neutron star systems. Nearly 10 percent of known pulsars are in binary systems with most of them orbiting white dwarf companion stars. The Pulsar has been found with the widest separation from the other star in the binary neutron system.
During Pulsar Search Collaboratory (PSC) workshop in summer, students who are interested in analyzing survey data collected by Green Bank Telescope (GBT), spend weeks in checking data plots and searching for unique signatures of pulsars.
The Pulsar Search Collaboratory is a joint venture between the National Radio Astronomy Observatory and West Virginia University which offers real research opportunity to students.
In a research paper accepted by the Astrophysical Journal, lead author Joe Swiggum, a graduate student in physics and astronomy at West Virginia University in Morgantown, said, “Pulsars are some of the most extreme objects in the universe. The students' discovery shows one of these objects in a really unique set of circumstances.”
The object has been codenamed PSR J1930-1852 by astronomers. It was discovered in 2012 by Cecilia McGough from Strasburg High School in Virginia and De'Shang Ray from Paul Laurence Dunbar High School in Baltimore, Maryland.
The discovery of a pulsar with extra wide orbit could help in understanding the concepts behind binary neutron star systems. Nearly 10 percent of known pulsars are in binary systems with most of them orbiting white dwarf companion stars. The Pulsar has been found with the widest separation from the other star in the binary neutron system.
During Pulsar Search Collaboratory (PSC) workshop in summer, students who are interested in analyzing survey data collected by Green Bank Telescope (GBT), spend weeks in checking data plots and searching for unique signatures of pulsars.
The Pulsar Search Collaboratory is a joint venture between the National Radio Astronomy Observatory and West Virginia University which offers real research opportunity to students.
“Space is just the construct that gives the illusion that there are separate objects” – Dr. Quantum (see video below)There is a phenomenon so strange, so fascinating, and so counter to what we believe to be the known scientific laws of the universe, that Einstein himself could not wrap his head around it. It’s called “quantum entanglement,” though Einstein referred to it as “spooky action at a distance.”An [...]
An artist's impression of the planet HATS-6b, orbiting the star, HATS-6. (Supplied: ANU) Excerpt from abc.net.au A "puffy" new planet orbiting a small, cool star has been discovered 500 light years away from Earth, by a team of scientists c...
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The Hooker 100-inch reflecting telescope at the Mount Wilson Observatory, just outside Los Angeles. Edwin Hubble's chair, on an elevating platform, is visible at left. A view from this scope first told Hubble our galaxy isn't the only one. Courtesy of The Observatories of the Carnegie Institution for Science Collection at the Huntington Library, San Marino, Calif. |
Excerpt from hnpr.org
The Hubble Space Telescope this week celebrates 25 years in Earth's orbit. In that time the telescope has studied distant galaxies, star nurseries, planets in our solar system and planets orbiting other stars.
But, even with all that, you could argue that the astronomer for whom the telescope is named made even more important discoveries — with far less sophisticated equipment.
A young Edwin Hubble at Mount Wilson's 100-inch telescope circa 1922, ready to make history.
Edwin Hubble Papers/Courtesy of Huntington Library, San Marino, Calif.
In the 1920s, Edwin Hubble was working with the 100-inch Hooker telescope on Mount Wilson, just outside Los Angeles. At the time, it was the largest telescope in the world.
On a chilly evening, I climb up to the dome of that telescope with operator Nik Arkimovich and ask him to show me where Hubble would sit when he was using the telescope. Arkimovich points to a platform near the top of the telescope frame.
"He's got an eyepiece with crosshairs on it," Arkimovich explains. The telescope has gears and motors that let it track a star as it moves across the sky. "He's got a paddle that allows him to make minor adjustments. And his job is to keep the star in the crosshairs for maybe eight hours."
"It's certainly much, much easier today," says John Mulchaey, acting director of the observatories at Carnegie Institution of Science. "Now we sit in control rooms. The telescopes operate brilliantly on their own, so we don't have to worry about tracking and things like this."
The headquarters of the Carnegie observatories is at the foot of Mount Wilson, in the city of Pasadena. It's where Hubble worked during the day.
A century's worth of plates are stored here in the basement. Mulchaey opens a large steel door and ushers me into a room filled with dozens of file cabinets.
"Why don't we go take a look at Hubble's famous Andromeda plates," Mulchaey suggests.
The plates are famous for a reason: They completely changed our view of the universe. Mulchaey points to a plate mounted on a light stand.
"This is a rare treat for you," he says. "This plate doesn't see the light of day very often."
This glass side of a photographic plate shows where Hubble marked novas. The red VAR! in the upper right corner marks his discovery of the first Cepheid variable star — a star that told him the Andromeda galaxy isn't part of our Milky Way.
Courtesy of the Carnegie Observatories
The plate shows the spiral shape of the Andromeda galaxy. Hubble was looking for exploding stars called novas in Andromeda. Hubble marked these on the plate with the letter "N."
"The really interesting thing here," Mulchaey says, "is there's one with the N crossed out in red — and he's changed the N to VAR with an exclamation point."
Hubble had realized that what he was seeing wasn't a nova. VAR stands for a type of star known as a Cepheid variable. It's a kind of star that allows you to make an accurate determination of how far away something is. This Cepheid variable showed that the Andromeda galaxy isn't a part of our galaxy.
At the time, most people thought the Milky Way was it — the only galaxy in existence.
"And what this really shows is that the universe is much, much bigger than anybody realizes," Mulchaey says.
It was another blow to our human conceit that we are the center of the universe.
Hubble went on to use the Mount Wilson telescope to show the universe was expanding, a discovery so astonishing that Hubble had a hard time believing it himself.
If Hubble could make such important discoveries with century-old equipment, it makes you wonder what he might have turned up if he'd had a chance to use the space telescope that bears his name.
| Artist's concept of the black hole. |
Excerpt from finance.yahoo.com
Of all the bizarre quirks of nature, supermassive black holes are some of the most mysterious because they're completely invisible.
But that could soon change.
Black holes are deep wells in the fabric of space-time that eternally trap anything that dares too close, and supermassive black holes have the deepest wells of all. These hollows are generated by extremely dense objects thousands to billions of times more massive than our sun.
Not even light can escape black holes, which means they're invisible to any of the instruments astrophysicists currently use. Although they don't emit light, black holes will, under the right conditions, emit large amounts of gravitational waves — ripples in spacetime that propagate through the universe like ripples across a pond's surface.
And although no one has ever detected a gravitational wave, there are a handful of instruments around the world waiting to catch one.
Game-changing gravitational waves
This illustration shows two spiral galaxies - each with supermassive black holes at their center - as they are about to collide.
Albert Einstein first predicted the existence of gravitational waves in 1916. According to his theory of general relativity, black holes will emit these waves when they accelerate to high speeds, which happens when two black holes encounter one another in the universe.
As two galaxies collide, for example, the supermassive black holes at their centers will also collide. But first, they enter into a deadly cosmic dance where the smaller black hole spirals into the larger black hole, moving increasingly faster as it inches toward it's inevitable doom. As it accelerates, it emits gravitational waves.
Astrophysicists are out to observe these waves generated by two merging black holes with instruments like the Laser Interferometer Gravitational-Wave Observatory.
"The detection of gravitational waves would be a game changer for astronomers in the field," Clifford Will, a distinguished profess of physics at the University of Florida who studied under famed astrophysicist Kip Thorne told Business Insider. "We would be able to test aspects of general relativity that have not been tested."
Because these waves have never been detected, astrophysicists are still trying to figure out how to find them. To do this, they build computer simulations to predict what kinds of gravitational waves a black hole merger will produce.
Learn by listening
In the simulation below, made by Steve Drasco at California Polytechnic State University (also known as Cal Poly), a black hole gets consumed by a supermassive black hole about 30,000 times as heavy.
You'll want to turn up the volume.
What you're seeing and hearing are two different things.
The black lines you're seeing are the orbits of the tiny black hole traced out as it falls into the supermassive black hole. What you're hearing are gravitational waves.
"The motion makes gravitational waves, and you are hearing the waves," Drasco wrote in a blog post describing his work.
Of course, there is no real sound in space, so if you somehow managed to encounter this rare cataclysmic event, you would not likely hear anything. However, what Drasco has done will help astrophysicists track down these illusive waves.
Just a little fine tuning
Gravitational waves are similar to radio waves in that both have specific frequencies. On the radio, for example, the number corresponding to the station you're listening to represents the frequency at which that station transmits.
3D visualization of gravitational waves produced by 2 orbiting black holes. Right now, astrophysicists only have an idea of what frequencies two merging black holes transmit because they’re rare and hard to find. In fact, the first ever detection of an event of this kind was only announced this month.
Therefore, astrophysicists are basically toying with their instruments like you sometimes toy with your radio to find the right station, except they don’t know what station will give them the signal they’re looking for.
What Drasco has done in his simulation is estimate the frequency at which an event like this would produce and then see how that frequency changes, so astrophysicists have a better idea of how to fine tune their instruments to search for these waves.
Detecting gravitational waves would revolutionize the field of astronomy because it would give observers an entirely new way to see the universe. Armed with this new tool, they will be able to test general relativity in ways never before made possible.
Excerpt from thespacereporter.com
A team of scientists has created a detailed map of our cosmic “neighborhood” extending nearly two billion lights years in every direction. This 3-D map showing galaxies in their superclusters will aid astrophysicists in better understanding how matter, including dark matter, is distributed in the universe.
According to a Science Daily report, the map indicates the relative concentration of galaxies in different areas, including the largest nearby supercluster called the Shapely Concentration, as well as less explored areas. The scientists found no sign of any pattern in the distribution of matter.
“The galaxy distribution isn’t uniform and has no pattern. It has peaks and valleys much like a mountain range. This is what we expect if the large-scale structure originates from quantum fluctuations in the early universe,” Mike Hudson of the University of Waterloo said in a statement.
The researchers hope that a more complete view of the placement and movement of matter will aid in forming predictions about the expansion of the universe. In particular, the team hopes to gain insight into the phenomenon of peculiar velocity – the differences in galactic movement caused by the unevenness in the expansion of the universe. It is thought that the non-uniform movement of galaxies is influenced by dark matter – a form of matter only indirectly detectable through its gravitational influence on light and visible matter.
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| A cross-section of the cosmic map detailing accumulations of massive clusters. The dark red region is the famous Shapley Concentration, the largest collection of galaxies in the nearby universe. Hudson et al./University of Waterloo |
“A better understanding of dark matter is central to understanding the formation of galaxies and the structures they live in, such as galaxy clusters, superclusters and voids,” said Hudson.
The team plans to continue expanding and detailing the map in collaboration with additional researchers. The team’s work was published in the journal Monthly Notices of the Royal Astronomical Society.
Excerpt from thespacereporter.com
As explained by Nature World News, “a mathematical description of the Universe actually requires one fewer dimension than it seems” according to the “holographic principle,” which would indicate that what appears to be a 3-D universe may actually “just be the image of 2-D processes on a huge cosmic horizon.”
Prior to this study, scientists looked into this holographic principle by applying their calculations to a universe presenting Anti de Sitter space. Anti de Sitter is the term used to describe space as having a hyperbolic shape, much like a saddle. This hyperbolic space shape behaves, mathematically, as special relativity would predict.
Special relativity is a theory put forth by Albert Einstein to describe the relationship between space and time, and is especially useful when studying very small particles moving at extreme speeds over cosmic distances. The concept of Anti de Sitter space assumes that spacetime itself is hyperbolic in its natural state, in the absence of matter or energy.
A team at the Vienne University of Technology looked at the holographic principle not in the usual Anti de Sitter space framework, but instead applied the principle to flat spacetime, as represents our physical universe.“Our Universe, in contrast, is quite flat – and on astronomic distances, it has positive curvature,” team member Daniel Grumiller said in a statement.
The team created several gravitational theories that apply to flat space to see if calculations regarding quantum gravity would indicate a holographic description as has occurred in former calculations with theories applied to Anti de Sitter space.
“If quantum gravity in a flat space allows for a holographic description by a standard quantum theory, then there must be physical quantities, which can be calculated in both theories – and the results must agree,” Grumiller said.
The team found that the amount of quantum entanglement required for gravitational theory models expressed the same value in flat quantum gravity as in a low dimensional field theory, showing that the theory of a holographic universe can be successfully applied to the reality of the relatively flat field of spacetime evident in our universe.
“This calculation affirms our assumption that the holographic principle can also be realized in flat spaces. It is evidence for the validity of this correspondence in our universe” team member Max Riegler said.
The results were published in the journal Physical Review Letters.
A Type Ia supernova, SN1994D, is shown exploding in lower left corner of the image at the top of the page of the galaxy NGC 4526 taken by the Hubble Space Telescope. (High-Z Supernova Search Team, HST, NASA)Excerpt from dailygalaxy.com Cer...
Excerpt from earthsky.org
Since 1975, when Hawking showed that black holes evaporate from our universe, physicists have tried to explain what happens to a black hole’s information.
What happens to the information that goes into a black hole? Is it irretrievably lost? Does it gradually or suddenly leak out? Is it stored somehow? Physicists have puzzled for decades over what they call the information loss paradox in black holes. A new study by physicists at University at Buffalo – published in March, 2015 in the journal in Physical Review Letters – shows that information going into a black hole is not lost at all.
Instead, these researchers say, it’s possible for an observer standing outside of a black hole to recover information about what lies within.
Dejan Stojkovic, associate professor of physics at the University at Buffalo, did the research with his student Anshul Saini as co-author. Stojkovic said in a statement:
Stojkovic says his research “marks a significant step” toward solving the information loss paradox, a problem that has plagued physics for almost 40 years, since Stephen Hawking first proposed that black holes could radiate energy and evaporate over time, disappearing from the universe and taking their information with them.
Disappearing information is a problem for physicists because it’s a violation of quantum mechanics, which states that information must be conserved.
Stojkovic says that physicists – even those who believed information was not lost in black holes – have struggled to show mathematically how the information is preserved. He says his new paper presents explicit calculations demonstrating how it can be preserved. His statement from University at Buffalo explained:
Bottom line: Since 1975, when Stephen Hawking and Jacob Bekenstein showed that black holes should slowly radiate away energy and ultimately disappear from the universe, physicists have tried to explain what happens to information inside a black hole. Dejan Stojkovic and Anshul Saini, both of University at Buffalo, just published a new study that contains specific calculations showing that information within a black hole is not lost.
What happens to the information that goes into a black hole? Is it irretrievably lost? Does it gradually or suddenly leak out? Is it stored somehow? Physicists have puzzled for decades over what they call the information loss paradox in black holes. A new study by physicists at University at Buffalo – published in March, 2015 in the journal in Physical Review Letters – shows that information going into a black hole is not lost at all.
Instead, these researchers say, it’s possible for an observer standing outside of a black hole to recover information about what lies within.
Dejan Stojkovic, associate professor of physics at the University at Buffalo, did the research with his student Anshul Saini as co-author. Stojkovic said in a statement:
According to our work, information isn’t lost once it enters a black hole. It doesn’t just disappear.What sort of information are we talking about? In principle, any information drawn into a black hole has an unknown future, according to modern physics. That information could include, for example, the characteristics of the object that formed the black hole to begin with, and characteristics of all matter and energy drawn inside.
Stojkovic says his research “marks a significant step” toward solving the information loss paradox, a problem that has plagued physics for almost 40 years, since Stephen Hawking first proposed that black holes could radiate energy and evaporate over time, disappearing from the universe and taking their information with them.
Disappearing information is a problem for physicists because it’s a violation of quantum mechanics, which states that information must be conserved.
According to modern physics, any information related to an astronaut entering a black hole – for example, height, weight, hair color – may be lost. This notion is known as the ‘information loss paradox’ of black holes because it violates quantum mechanics. Artist’s concept via Nature.
In the 1970s, [Stephen] Hawking proposed that black holes were capable of radiating particles, and that the energy lost through this process would cause the black holes to shrink and eventually disappear. Hawking further concluded that the particles emitted by a black hole would provide no clues about what lay inside, meaning that any information held within a black hole would be completely lost once the entity evaporated.
Though Hawking later said he was wrong and that information could escape from black holes, the subject of whether and how it’s possible to recover information from a black hole has remained a topic of debate.
Stojkovic and Saini’s new paper helps to clarify the story.Stojkovic added:
Instead of looking only at the particles a black hole emits, the study also takes into account the subtle interactions between the particles. By doing so, the research finds that it is possible for an observer standing outside of a black hole to recover information about what lies within.
Interactions between particles can range from gravitational attraction to the exchange of mediators like photons between particles. Such “correlations” have long been known to exist, but many scientists discounted them as unimportant in the past.
These correlations were often ignored in related calculations since they were thought to be small and not capable of making a significant difference.
Our explicit calculations show that though the correlations start off very small, they grow in time and become large enough to change the outcome.
Artist’s impression of a black hole, via Icarus
Bottom line: Since 1975, when Stephen Hawking and Jacob Bekenstein showed that black holes should slowly radiate away energy and ultimately disappear from the universe, physicists have tried to explain what happens to information inside a black hole. Dejan Stojkovic and Anshul Saini, both of University at Buffalo, just published a new study that contains specific calculations showing that information within a black hole is not lost.
Excerpt from huffingtonpost.com
No one really knows whether we're alone or if the universe is brimming with brainy extraterrestrials. But that hasn't stopped scientists from trying to figure out what form intelligent aliens might take.
And as University of Barcelona cosmologist Dr. Fergus Simpson argues in a new paper, most intelligent alien species would likely exceed 300 kilograms (661 pounds)--with the median body mass "similar to that of a polar bear."
If such a being had human proportions, Simpson told The Huffington Post in an email, it would be taller than Robert Wadlow, who at 8 feet, 11 inches is believed to have been the tallest human who ever lived.
Robert Wadlow (1918-1940), the tallest man who ever lived.Simpson's paper, which is posted on the online research repository arXiv.org, is chockablock with formidable-looking mathematical equations. But as he explained in the email, his starting point was to consider the relationship between the number of individuals in a population on Earth and the body mass of those individuals:
"Ants easily outnumber us because they are small. Our larger bodies require a much greater energy supply from the local resources, so it would be impossible for us to match the ant population. Now apply this concept to intelligent life across the universe. On average, we should expect physically larger species to have fewer individuals than the smaller species. And, just like with countries, we should expect to be in one of the bigger populations. In other words, we are much more likely to find ourselves to be the ants among intelligent species."
Or, as Newsweek explained Simpson's argument, there are probably more planets with relatively small animals than planets with relatively large animals. It makes sense to assume that Earth is in the former category, so we can assume that humans are probably among the smaller intelligent beings.
What do other scientists make of Simpson's paper?
“I think the average size calculation is reasonable,” Dr. Duncan Forgan, an astrobiologist at the University of St. Andrews in Scotland who wasn't involved in the research, told Newsweek.
But to Dr. Seth Shostak, senior astronomer at the SETI Institute in Mountain View, Calif., the argument is suspect.
"There is an assumption here that intelligence can come in all (reasonable) sizes, and does so with more or less equal likelihood," Shostak told The Huffington Post in an email. "That may be true, but on Earth bigger has not always been better, at least in the brains department. Dolphins have higher IQs than whales, and crows are smarter than eagles. Octopuses are cleverer than giant squids, and obviously we’re smarter than polar bears."
Ultimately, Shostak said, we can’t know whether "little green men are actually big green men" before we actually make contact.
Until then!
Excerpt from thewestsidestory.net
The Universe is expanding and any student of astronomy will vouch to this fact. However according to a team of astronomers the acceleration of the universe may not be as quick as it was assumed earlier.
A team of astronomers have discovered that certain types of supernova are more varied than earlier thought of and in the process have led to the biggest mystery of the universe-how fast is the universe expanding after the big bang?
Peter A. Milne of the University of Arizona said, “We found that the differences are not random, but lead to separating Ia supernovae into two groups, where the group that is in the minority near us are in the majority at large distances — and thus when the universe was younger, there are different populations out there, and they have not been recognized. The big assumption has been that as you go from near to far, type Ia supernovae are the same. That doesn’t appear to be the case.”
Milne said, “The idea behind this reasoning, is that type Ia supernovae happen to be the same brightness — they all end up pretty similar when they explode. Once people knew why, they started using them as mileposts for the far side of the universe.The faraway supernovae should be like the ones nearby because they look like them, but because they’re fainter than expected, it led people to conclude they’re farther away than expected, and this in turn has led to the conclusion that the universe is expanding faster than it did in the past.”
Milne said, “We’re proposing that our data suggest there might be less dark energy than textbook knowledge, but we can’t put a number on it, until our paper, the two populations of supernovae were treated as the same population. To get that final answer, you need to do all that work again, separately for the red and for the blue population.
Type la supernovae are considered as a benchmark for far away sources of light they do have a fraction of variability which has limited our knowledge of the size of the universe.
The distance of objects with the aid of our binocular vision and the best space-based telescopes and most sophisticated techniques works out in the range of ten or twenty thousand light years.
However as compared to the vastness of space, this is just pea nuts.
For Distances greater than that it is imperative to compare the absolute and observed brightness of well understood objects and to use the difference to determine the object’s distance.
In astronomy it is difficult to find an object of known brightness since there are examples of both bright and dim stars and galaxies. However there is one event which can be used to work out its absolute brightness. Supernovas are the final stages of a dying star and it explodes with such violence, the flash can be seen across the vast universe.
Type la Supernovae occurs in a binary star system when a white dwarf scoops off mass from its fellow star. This reproducible mechanism gives a well determined brightness and therefore scientists term such Type la supernovae as ‘standard candles’.
Astronomers found that the Type la supernovae is so uniform that it has been designated as cosmic beacons and used to assess the depths of the universe. It is now revealed that they fall into different populations and are not very uniform as previously thought. .
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| WHAT’S FOR DINNER? Signals detected by the Parkes radio telescope (pictured) suggest that intelligent life in the universe has a penchant for leftovers. |
Excerpt from sciencenews.org
Mysterious radio signals detected by the Parkes telescope appear to come from an advanced civilization in the Milky Way.
Unfortunately, it’s the one civilization we already know about.
Microwave ovens opened before they’re done cooking have been muddling the hunt for far more distant radio signals, researchers report online April 9 at arXiv.org. Astronomers have had to contend with enigmatic flares dubbed “perytons” ever since discovering equally puzzling fast radio bursts, or FRBs (SN: 8/9/14, p. 22), in 2007. Perytons and FRBs are quite similar, except that astronomers realized that perytons originate on Earth, possibly from some meteorological phenomenon, while FRBs come from other galaxies.
Three perytons in January coincided with independently detected blasts of 2.4 gigahertz radio waves — the same frequency that microwave ovens use to heat food. So researchers at the Parkes telescope in Australia spent weeks heating mugs of water while moving the massive radio dish around the sky, trying to re-create the phenomenon. Finally, researchers tried opening the oven door mid-cooking instead of letting the timer run out. Suddenly, perytons started showing up in the data.
The source of the galactic FRBs remain an intriguing mystery. Astronomers suspect they have something to do with imploding neutron stars or eruptions on magnetars. At this point, however, they might want to consider extraterrestrials nuking frozen pizzas.
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