Tags: astronomy, Science
NASA has revealed that its Van Allen Probes have discovered a third, previously unknown, radiation belt around Earth. The belt appears to be transient, depending strongly on solar activity.
The Probes mission is part of NASA’s Living With a Star geospace program to explore the fundamental processes that operate throughout the solar system, in particular those that generate hazardous space weather effects near Earth and phenomena that could affect solar system exploration.
In what could perhaps be described as serendipitous, scientists had switched on key instruments on the the twin probes (which are described in detail in the second video below) just three days after launch from Cape Canaveral Air Force Station in Florida on August 30 last year.
That decision was made in order that observations would overlap with those of another mission, the Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX) – launched in 1992 – that was about to de-orbit and re-enter Earth’s atmosphere.
In practice it meant NASA’s mission scientists gathered data on the third radiation belt for four weeks before a shock-wave from the sun annihilated it.
The Van Allen Probes are studying an extreme and dynamic regions of space known as the Van Allen Radiation Belts.
These belts are critical regions of space for modern society. They are affected by solar storms and space weather and can change dramatically. They can pose dangers to communication and GPS satellites as well as humans in space – as I’ll discuss shortly.
Named after their discoverer, the late pioneering NASA astrophysicist James Van Allen, these concentric, donut shaped rings are filled with high-energy particles that gyrate, bounce, and drift through a region extending to 65,000 kilometres from the earth’s surface.
This belt is comprised mostly of high-energy protons, trapped within about 600-6,000 kilometres of Earth’s surface. Those particles are particularly damaging to satellites and humans in space. The International Space Station (ISS) orbits below this belt at 330-410 kilometres.
This larger belt is located 10,000 to 65,000 kilometres above Earth’s surface, and is at its most intense between 14,500 and 19,000 kilometres above Earth. The second belt is much more variable than the inner one. In addition to protons, it contains ions of oxygen and helium.
So what of the third belt? This new, outer zone is comprised mainly of high-energy electrons and very energetic positive ions (mostly protons). As reported recently in the journal Science, this torus formed on September 2 last year and persisted unchanged in a height range of 20,000-23,000 kilometres for four weeks. It was then disrupted by a shock-wave from the sun.
Space Weather Impacts on Earth
The radiation belts are part of a much larger space weather system driven by energy and material that erupt off the sun’s surface and fill the entire solar system. Besides emitting a continuous stream of plasma called the solar wind, the sun periodically releases billions of tons of matter in what are called coronal mass ejections.
These immense clouds of material, when directed towards Earth, can cause large magnetic storms in the space environment around Earth, the magnetosphere and the upper atmosphere.
The term space weather generally refers to conditions on the sun, in the solar wind, and within Earth’s magnetosphere, ionosphere and thermosphere that can influence the performance and reliability of space-borne and ground-based technological systems and can endanger human life or health.
Most spacecraft in Earth orbit operate partly or entirely within the radiation belts. During periods of intense space weather, the density of particles within the belts increases, making it more likely that a shuttle’s sensitive electronics will be hit by a charged particle.
Ions striking satellites can overwhelm sensors, damage solar cells, and degrade wiring and other equipment. When conditions get especially rough in the radiation belts, satellites often switch to a safe mode to protect their systems.
When high-energy particles – those moving with enough energy to knock electrons out of atoms – collide with human tissue, they alter the chemical bonds between the molecules that make up the tissue’s cells.
Sometimes the damage is too great for a cell to repair and it no longer functions properly. Damage to DNA within cells may even lead to cancer – causing mutations.
During geomagnetic storms, the increased density and energy of particles trapped in the radiation belts means a greater chance that an astronaut will be hit by a damaging particle.
That’s why the ISS has increased shielding around crew quarters, and why NASA carefully monitors each astronaut’s radiation exposure throughout his or her career.
The advances in technology and detection made by NASA in this mission already have had an almost immediate impact on both basic science and the space-based technology we all depend on.
Kevin Orrman-Rossiter does not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article, and has no relevant affiliations.
Tags: astronomy, funny things, Nature, Science
Our solar system is expecting a visitor called Comet Pan-STARRS, which might be visible in the evening sky during most of March.
Pan-STARRS came from the Oort Cloud, the enormous cloud of comets that surrounds our solar system. It contains ice and dust that have been frozen for billions of years, never having a chance to melt until now.
The comet has never been near the sun before, so scientists aren’t sure how it will react. Most of them estimate that it will be as bright as the stars in the Big Dipper.
“But prepare to be surprised,” said researcher Karl Battams in a NASA article. “A new comet from the Oort Cloud is always an unknown quantity equally capable of spectacular displays or dismal failures.”
As the comet is quite close to the sun, it should produce plenty of dust and therefore have a good tail.
“My guess is that the primary feature visible to the naked eye will be the gaseous coma around the head of the comet,” Matthew Knight of the Lowell Observatory said in the article.
“The comet’s tail will probably require binoculars or a small telescope.”
Comet Pan-STARRS will be closest to Earth on March 5—about 100 million miles away—and closest to the sun on March 10. However, the best time to see it might be March 12 and 13, when the comet may be seen next to the crescent moon in the twilight sky.
“Because of its small distance from the sun, Pan-STARRS should be very active, producing a lot of dust and therefore a nice dust tail,” Knight said. “However, it could still be difficult to see. From our point of view on Earth, the comet will be very close to the sun.”
“This means that it is only observable in twilight when the sky is not fully dark.”
The comet was named after the Panoramic Survey Telescope & Rapid Response System, the Hawaiian telescope used to discover it.
Related Articles: Eltanin Asteroid Could Have Triggered Ice Age
Tags: astronomy, Science
Deep images of the sky reveal that the universe contains billions of galaxies. Some, such as our own Milky Way, are immense, containing hundreds of billions of stars. Most galaxies, however, are dwarfs, being much smaller and with only a few billion stars.
Modern cosmology has proved to be amazingly accurate in predicting how galaxies are scattered through the universe. Instead of being randomly thrown about, galaxies seem to live together, some in clusters of a thousand individual systems, but most in groups of tens or hundreds.
But new research on dwarf galaxies by my colleagues and me–published in the journal Nature–seems to present a major challenge to ideas of how the universe actually works.
After more than a decade of study, we’ve discovered that small galaxies that accompany the nearest spiral galaxy to our own–the Andromeda Galaxy–are dancing together in a vast plane.
To understand why this is significant, we need to begin with what we know about the universe and our own cosmic backyard.
The Milky Way is located in the “Local Group”, a small patch of the universe it inhabits with the similar-sized Andromeda Galaxy, and a smaller spiral known as the Triangulum Galaxy.
Accompanying these larger systems are almost 100 dwarf galaxies. Those of us lucky enough to be living in the Southern Hemisphere can clearly see two of these dwarf galaxies in the night sky, namely the Large and Small Clouds of Magellan.
These many Local Group dwarfs tend to be grouped around the larger galaxies, precisely as predicted by our understanding of the expansion of the universe and the growth of cosmic structure. But it is precisely these dwarf galaxies that are proving to be a serious headache for the cosmological models they appear to be supporting.
Where Are All the Galaxies?
The first problem, known as the “missing satellite problem,” has been known for more than a decade. While the almost-100 galaxies in the Local Group may sound impressive, this is far fewer than the several thousand predicted by cosmological theories.
Some believe that our diminutive dwarf galaxy population is a crippling blow to the prevailing “cold dark matter” model of galaxy formation–that is, the idea that dominant component of mass in the universe is invisible to us, the scary-sounding dark matter which shepherds atoms into the stars and galaxies that we see.
Others, however, think there is no crisis, suggesting the dwarfs are out there as starless dark matter halos, having lost their gas–the raw material for forming new stars–due to the explosions of super-stars in the very early universe.
This neatly brings us to our result in the Nature paper.
For more than 10 years I have been part of a collaboration that has been trying to map out the extensive stellar halo of Andromeda.
This tenuous distribution of stars, which extends hundreds of thousands of light years away from the Andromeda Galaxy, is made from the remnants of small galaxies that have strayed too close and have been cannibalised by the larger galaxy.
Over the years, our collaboration has used large telescopes and sensitive instruments to map out the immense portion of the sky that encompasses Andromeda’s halo. Since 2008, we have used the 3.6m Canada-France-Hawaii Telescope to undertake the Pan-Andromeda Archaeological Survey (or, more cutely, PAndAS).
Now that the data-taking and processing is complete, the scientific results from PAndAS are starting to flow. As well as the stellar halo, there are large, extended shreds of stars, the ongoing cannibalization of other systems and lots of globular clusters – small balls of a million stars living together.
The dwarf galaxies were found to be rotating in a giant plane around Andromeda.
Within PAndAS we found almost 30 dwarf galaxies orbiting Andromeda, most of which were identified only in the past few years. With the quality of the PAndAS data, PhD student Anthony Conn was able to accurately measure the distances to each of the dwarf galaxies and, for the first time, we knew the three-dimensional distribution of dwarf galaxies surrounding Andromeda.
What do our theoretical models for the structure and evolution of galaxies tell us about the expected distribution of dwarf galaxies around large galaxies? While we know there are not as many dwarfs as predicted, our models tell us that the ones we do see should be buzzing around randomly like a swarm of angry bees.
So, what do we see with the dwarfs orbiting Andromeda? On the face of it, it seems that the theoretical predictions are borne out, with the dwarfs seemingly distributed at random.
But we decided to look a little deeper and see if there was any underlying structure in the dwarf galaxy population. Instead of considering the entire dwarf population, we instead looked for structure subsamples of galaxies, comparing the actual distributions to many thousands of randomly generated samples.
What we found surprised us, with 13 dwarf galaxies lying in an extremely thin plane, 45,000 light-years thick, but immense in size–1.2 million light years in diameter. Such a configuration would appear extremely rarely in a randomly distributed population of dwarfs.
Rather strangely, the edge of this plane points towards the Milky Way; the plane could have been oriented in any direction, but is this mysterious alignment telling us something about the planes origin?
Numerical simulation of the formation of a filament containing hundreds of galaxies.
Only the Beginning
But there were more surprises to come. As the dwarfs were initially discovered, they became the targets of the world’s largest telescopes, using the Doppler shift of light to measure the velocities of the individual galaxies. What we found stopped us in our tracks.
The dwarfs north of Andromeda were moving towards us, while those in the south were moving away from us. That is, this vast plane of dwarfs is rotating!
Remember, nothing like this plane is predicted in our cosmological models.
The mystery deepens when we look closer to home where there has been growing evidence that the Milky Way possesses its own plane of dwarf galaxies, known as Vast Polar Structure (VPoS).
Perversely, studying our own galaxy’s stellar halo is more challenging than that of Andromeda as we need to image the entire sky, but the evidence is growing stronger that the Milky Way and Andromeda possess unexplained planes of dwarf galaxies.
What are they doing there?
Some have suggested that what we see are not normal dwarf galaxies, but are actually “tidal dwarfs”, small agglomerations of stars that form from the debris when a large galaxy tears apart a smaller one.
But such dwarfs are transitory and quickly disperse, so such planes should be rare and we would be extremely lucky to see them in both the Milky Way and Andromeda at the same time.
Furthermore, if what we are seeing are truly tidal dwarfs then we are missing even more of the satellite galaxies predicted by our theories for the growth of structure in the universe.
Hence we are faced with a serious cosmological conundrum, a problem that our current theoretical models have to explain if we are to have faith that they are an accurate description of the universe around us.
And if they cannot, well, we mightn’t have to go right back to the drawing-board, but we will need to question our underlying assumptions on things like the nature of dark matter.
Some already think the existence of these planes is telling us that we should be questioning the more fundamental properties of the universe, including the very existence of dark matter and even the action of gravity.
So, what is the solution? Honestly, I do not know, but it is going to be fun trying to find out.
This article was originally published on The Conversation.
Related Articles: Disc of Dwarf Galaxies Dancing Around Andromeda
Tags: astronomy, Science
Over the past few months our planet has been impacted by an increasing number of solar explosions that have erupted from the sun’s surface.
Even though next year’s predicted solar maximum–the period of greatest activity in the sun’s 11-year cycle–is expected to be smaller than its predecessor a decade ago, the impact on society over the coming months could be worse than in the past.
The main reason for this is that there has been an increase in society’s dependence on space-based services that are severely influenced by these disturbances.
The effect that space weather has on our everyday lives resides in our reliance on technology, in particular electricity grids, radio communications and satellite-based services.
While our reliance on electric power is obvious, our reliance on radio communications may not be.
By “radio communications” I don’t just mean walkie-talkies and two-way radios. Military organizations around the world, including Australia’s defense forces, heavily utilize ground-based radar surveillance for routine border protection, and have done so since the end of the second world war.
An additional aspect of our current technology that is strongly influenced by space weather events is satellite communications. This not only includes both satellite phones and TV broadcasting, but also satellite positioning services, such as the Global Positioning System (GPS).
The direct effects of space weather events on our satellite communications are twofold:
1) Satellites are subjected to high radiation doses from the space environment that can cause hardware faults and failures.
2) Satellite-transmitted radio signals are manipulated by the layer of partially ionized gas in Earth’s upper atmosphere–the ionosphere.
One example in which satellites succumbed to the sun’s wrath was the loss of two Canadian telecommunications satellites that were subjected to an intense geomagnetic disturbance in 1994. The satellites were replaced at a cost of about US$400 million.
Earth’s ionosphere is a dominant source of error in GPS positioning due to its effects on radio signals passing through the atmosphere. The commercial “SATNAVs”, and more recently smartphones, that people commonly use for navigation across town are accurate to within a few tens of meters, and therefore a drop in accuracy using these devices during geomagnetic storms may not be obvious.
But industries that conduct high-precision (centimeter-level) positioning operations, such as surveying and exploration mining, are strongly impacted by space weather disturbances.
Drag and Drop
A less direct space weather effect on our technological infrastructure is the dramatically increased level of atmospheric drag experienced by low-Earth orbiting satellites as the upper atmosphere swells due to the increased heating during geomagnetic storms.
Low-Earth orbit satellites reside (generally speaking) at altitudes lower than 2,000km and a large portion of those are Earth Observation Satellites (or EOS for short).
Many Australians would be unaware of how much our government departments and organizations rely on EOS in their day-to-day operations. The Federal Government spends about A$100 million per year on EOS data acquisition.
The services provided with this data contribute A$3.3 billion towards the annual Australian gross domestic product (GDP). This means the government gets more than a 30-fold return on its EOS data investment, despite not owning any EOS currently in orbit.
So even though Australia owns very few orbiting satellites, its economy is actually rather heavily reliant on space-based services.
An example of the adverse impact that satellite data gaps have on Australia is the LANDSAT EOS data loss due to retiring and malfunctioning satellites.
This costs Australia an estimated A$100 million in the first year–the federal government’s entire yearly investment–with flow-on effects expected in subsequent years until replacements are launched.
Lost in Space
Readers may remember back to 1989 when a large geomagnetic storm destroyed power transformers in Canada, and caused widespread blackouts and circuit trips across Northern America.
But one problem caused by this geomagnetic storm that was far less publicized at the time was that around 1,500 orbiting objects were completely lost by the North American Aerospace Defense Command (NORAD).
Composing the vast majority of these lost objects were space debris or “space junk”.
The rest were operational satellites worth millions of dollars. One of the lost objects was later found to be orbiting at an altitude 30km lower than it was prior to the storm. It took NORAD more than seven days to find all of the objects again and to resume normal operations.
From the LANDSAT example above, it is easy to see how vulnerable the Australian economy is to the loss of EOS, due to collisions with space debris, in particular during the days following a large geomagnetic disturbance.
Space weather prediction is a challenging task that a number of organizations around the world specialize in. Those organizations include, but are not limited to, the NOAA Space Weather Prediction Center in the USA, the Solar Influences Data Analysis Center in Belgium and the Australian Space Forecast Center–the space weather branch within the Bureau of Meteorology.
The importance of the work these organizations do is significantly increasing as we become more heavily reliant on technology into the future.
It is therefore important that space scientists and space weather forecasters internationally remain focused on studying these impacts in the context of providing accurate forecasts for individuals and industries that rely on these technologies.
The next solar maximum will be a testing time.
This article was originally published by The Conversation.
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Tags: astronomy, Science
The universe may develop according to similar as yet unknown laws that control the growth of other complex networks like the human brain and the Internet.
Using a supercomputer and other calculations, an international research team found that the causal network representing space-time is a graph that looks like other systems, such as social or biological networks.
“By no means do we claim that the universe is a global brain or a computer,” said study co-author Dmitri Krioukov at the University of California-San Diego in a press release.
“But the discovered equivalence between the growth of the universe and complex networks strongly suggests that unexpectedly similar laws govern the dynamics of these very different complex systems.”
Krioukov believes this pattern is not a coincidence.
“Of course it could be, but the probability of such a coincidence is extremely low,” he said. “Coincidences in physics are extremely rare, and almost never happen.”
“There is always an explanation, which may be not immediately obvious.”
The results are important for cosmology and network science.
“Such an explanation could one day lead to a discovery of common fundamental laws whose two different consequences or limiting regimes are the laws of gravity (Einstein’s equations in general relativity) describing the dynamics of the universe, and some yet-unknown equations describing the dynamics of complex networks,” said study co-author Marián Boguñá at Spain’s Universitat de Barcelona in the release.
The findings were published in Nature’s Scientific Reports on Nov. 16.
Related Articles: Microcosmic Threads Weave Fabric of Our Universe Together
Tags: archaeology, astronomy, Body & Mind, CCP, Children, China, Chinese culture, Falun Gong, Food, health, human rights, human rights lawyers, Nature, persecution of dissidents, Shen Yun, Society, technology
The blog is now taking its annual summer break.
I wish you all a really nice summer with sun, sea, forest, togetherness and everything you need to fill yourself up with, before the short days of wintertime that unavoidable will be here. Here in Sweden we really enjoy our light season and the nordic light!
See you all in August. Rainy days I might fill in with links to articles. But no musts, otherwise it isn’t a holiday🙂 Please check out Twitter, in the sidebar to the right, as well.
Have a really nice Summer🙂
Links to interesting articles:
Tags: astronomy, Science, science in quotes
“I’m not an atheist. I don’t think I can call myself a pantheist. The problem involved is too vast for our limited minds. We are in the position of a little child entering a huge library filled with books in many languages. The child knows someone must have written those books. It does not know how. It does not understand the languages in which they are written. The child dimly suspects a mysterious order in the arrangement of the books but doesn’t know what it is. That, it seems to me, is the attitude of even the most intelligent human being toward God. We see the universe marvelously arranged and obeying certain laws but only dimly understand these laws.”
—Albert Einstein, in “Relativity: The Special and General Theory”
Albert Einstein was a physicist best known for his theory of relativity. He won the Nobel Prize in Physics in 1921 for his discovery of the photoelectric effect and other contributions to theoretical physics.
Einstein’s work in relativity pointed out limitations in Isaac Newton’s classical mechanics and contributed to the rise of quantum physics. It led to astronomical discoveries including black holes, neutron stars, and gravitational waves.
Join The Epoch Times in celebrating the Chinese New Year with this article on a modern analysis of the Chinese ancients’ observation of a supernova 2,000 years ago!
An ancient celestial event observed by Chinese astronomers almost two millennia ago has been explained using NASA’s Spitzer Space Telescope and Wide-field Infrared Survey Explorer WISE.
Scientists in the 1960s identified the phenomenon as the first supernova recorded in history, but its spherical remains are much bigger than expected.
The remnants of the explosion are known as RCW 86, and are located about 8,000 light-years away. The supernova occurred in a hollowed-out cavity, emitting matter much further and faster than normal.
“This supernova remnant got really big, really fast,” said lead researcher Brian J. Williams at North Carolina State University in a press release.
“It’s two to three times bigger than we would expect for a supernova that was witnessed exploding nearly 2,000 years ago. Now, we’ve been able to finally pinpoint the cause.”
The explosion was described as a “guest star” by the Chinese in 185 A.D. According to the Book of the Later Han, written in 445 A.D., the supernova was spotted in October (in the Chinese calendar) of that year, and remained until June of the following year.
The guest star is said to have had five colors, and fortune tellers saw it as an omen of war. Later, it was thought to be associated with a war that broke out in 189 A.D., causing thousands of deaths.
The new study, published online in the Astrophysical Journal, shows that it is a Type Ia supernova generated by the death of a white dwarf star.
Tags: astronomy, Science
As the sun approaches solar maximum in 2013, new light has been shed upon the effect of solar events on our planet’s magnetosphere, according to a study to be published in Nature Physics on Jan. 29.
Astronomers at the University of California-Los Angeles (UCLA) have discovered that most of the electrons in the Earth’s outer radiation belt vanish at the start of a geomagnetic storm, only to reappear a few hours later. This doughnut-shaped region is full of energetic electrons traveling at almost light speed.
“It’s a puzzling effect,” said study co-author Vassilis Angelopoulos in a press release. “Oceans on Earth do not suddenly lose most of their water, yet radiation belts filled with electrons can be rapidly depopulated.”
Originally noticed by scientists in the 1960s, the team elucidated this mystery using data collected from a fleet of orbiters, including NASA’s THEMIS spacecraft (Time History of Events and Macroscale Interactions during Substorms).
“What we are studying was the first discovery of the space age,” said study co-author Yuri Shprits in the release. “People realized that launches of spacecraft didn’t only make the news, they could also make scientific discoveries that were completely unexpected.”
Tags: astronomy, Science
Extrasolar planets may be more abundant in our galaxy than previously thought, according to new research to be published in Nature on Jan. 12.
Using a technique called gravitational microlensing, astronomers from the European Southern Observatory (ESO) spent six years surveying millions of stars in the Milky Way and found that a star will probably be orbited by more than one planet.
Previously, two methods have been used to find exoplanets: detection of the planet’s gravitational pull on its host star, and observing the planet dimming its star’s light as it passes in front of it.
However, these techniques are best for locating planets that are massive or circling their stars closely. Consequently, many other exoplanets may be missed. In contrast, gravitational lensing can find planets with a wide range of masses, as well as those orbiting their suns at a distance.
“We have searched for evidence for exoplanets in six years of microlensing observations,” said study lead author Arnaud Cassan at France’s Institut d’Astrophysique de Paris in a press release. “Remarkably, these data show that planets are more common than stars in our galaxy.”
“We also found that lighter planets, such as super-Earths or cool Neptunes, must be more common than heavier ones.”
The gravitational field of a star can act as a lens, magnifying the brightness of a background star. If a planet is circling the lensing star, it adds to the magnifying effect. The scientists looked for this effect in data from the PLANET (Probing Lensing Anomalies NETwork) and OGLE (Optical Gravitational Lensing Experiment) surveys.
Despite the technique’s power, its planet-hunting potential is limited by the coincidence of two factors: the chance that a background and lensing star will align correctly is very rare, and the planet’s orbit needs to be aligned too.
Three exoplanets were discovered during the six-year search—a super-Earth and two planets with masses similar to Neptune and Jupiter. This is a good outcome for such a fine-tuned technique, suggesting that the astronomers were either very lucky or exoplanets are commonplace in our galaxy.
In their statistical analysis, the scientists included seven other exoplanets, and the many non-detections from the observations, to determine that one in six of the stars surveyed hosts a Jupiter-like planet, half of them have Neptune-mass planets, and two-thirds have super-Earths.
“We used to think that the Earth might be unique in our galaxy,” concluded study co-lead author Daniel Kubas at the ESO in the release. “But now it seems that there are literally billions of planets with masses similar to Earth orbiting stars in the Milky Way.”
- Habitable Exoplanets Catalog: An Online Database of Liveable Worlds
- Youngest Exoplanet Spotted Being Born
- Microcosmic Threads Weave Fabric of Our Universe Together
- Astronomers Find Two-Star Systems Common in Universe
Tags: astronomy, Nature, Science
Tranquillityite was known to exist only on moon rocks and lunar meteorites until its recent discovery at six widely scattered sites in Western Australia, and could be more common on Earth than previously thought.
Tranquillityite has no economic value, but scientists say it can be used to age-date rocks in which it is found through measuring the proportions of radioactive isotopes in the mineral.
The substance is named after the Sea of Tranquility on the moon, where Apollo 11 astronauts landed in 1969. Scientists found three previously unknown minerals in collected samples of lunar igneous rocks: armalcolite, pyroxferroite, and tranquillityite. The first two minerals were later found on Earth within about a decade, but tranquillityite would remain hidden for over 40 years.
Tags: astronomy, funny things, Science
NASA Ames Research Center
NASA’s Kepler mission has confirmed its first planet in the “habitable zone,” the region where liquid water could exist on a planet’s surface. Kepler also has discovered more than 1,000 new planet candidates, nearly doubling its previously known count. Ten of these candidates are near-Earth-size and orbit in the habitable zone of their host star. Candidates require follow-up observations to verify they are actual planets.
The newly confirmed planet, Kepler-22b, is the smallest yet found to orbit in the middle of the habitable zone of a star similar to our sun. The planet is about 2.4 times the radius of Earth. Scientists don’t yet know if Kepler-22b has a predominantly rocky, gaseous or liquid composition, but its discovery is a step closer to finding Earth-like planets.
Previous research hinted at the existence of near-Earth-size planets in habitable zones, but clear confirmation proved elusive. Two other small planets orbiting stars smaller and cooler than our sun recently were confirmed on the very edges of the habitable zone, with orbits more closely resembling those of Venus and Mars.
“This is a major milestone on the road to finding Earth’s twin,” said Douglas Hudgins, Kepler program scientist at NASA Headquarters in Washington. “Kepler’s results continue to demonstrate the importance of NASA’s science missions, which aim to answer some of the biggest questions about our place in the universe.”
Tags: astronomy, Science
Electromagnetism appears to vary with location, according to new research, which challenges one of science’s most fundamental principles–that the laws of physics remain constant across the universe.
The study found that electromagnetism, one of the four known fundamental forces in nature, seems to differ across the universe. Electromagnetism is measured as the fine-structure constant and is represented by the symbol alpha.
Variation in alpha’s value was first observed a decade ago by John Webb and Victor Flambaum at Australia’s New South Wales University (UNSW) and colleagues, after analyzing observations of a large area in the sky from the Keck Observatory in Hawaii.
As part of a new international effort, the number of observations has now been doubled and the value of alpha measured in approximately 300 distant galaxies, using the European Southern Observatory’s Very Large Telescope in Chile.
“The results astonished us,” Webb said in a media release. “In one direction–from our location in the universe–alpha gets gradually weaker, yet in the opposite direction it gets gradually stronger.”
If confirmed, the discovery will have profound implications regarding our understanding of time-space as it violates one of the fundamental principles underlying Einstein’s General Relativity theory, Webb said.
“Such violations are actually expected in some more modern ‘Theories of Everything’ that try to unify all the known fundamental forces,” said Flambaum. “The smooth continuous change in alpha may also imply the universe is much larger than our observable part of it, possibly infinite.”
This research may have even wider significance.
“Even a slight change in the laws of nature means they weren’t ‘set in stone’ when our universe was born,” he continued. “The laws of nature you see may depend on your ‘space-time address’–when and where you happen to live in the universe.”
Webb said that the findings could also explain why the laws of nature appear to support the existence of life.
“The answer may be that other regions of the universe are not quite so favorable for life as we know it, and that the laws of physics we measure in our part of the universe are merely ‘local by-laws’, in which case it is no particular surprise to find life here,” he concluded.
The study was published in Physical Review Letters on Oct. 31.
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Tags: astronomy, Science
Einstein hypothesized that the universe is like a flat sheet that runs on forever, deformed by matter such as stars and galaxies. However, scientists continue to question whether the universe really is infinite.
The further away a galaxy or star is from Earth, the older it is. Today, we can see back to a maximum of about 13 billion years ago where there is a space containing the aftershock of the big bang.
This space is filled with gas and plasma so hot that light cannot pass through, forming a layer of cosmic microwave background radiation that is separating us from a possible boundary of the universe.
But regardless of our limited ability to research the space beyond, cosmologists use logic to reason that our universe is finite.
According to the big bang theory, the universe was once a small condensed ball of energy. When it exploded, all the matter and space in that ball expanded outwards, and continues to expand to this day, making it an infinite universe.
However, physicist Andreas Albrecht at University of California, Davis compares the expanding universe to blowing a bubble. He says inflation must stop when space gets to a certain maximum size which he predicts is about 20 percent bigger than its current size.
Cosmologist Neil Cornish at Montana State University agrees that the universe is finite.
“So one problem with an infinite universe—it’s not just infinite in space, but also infinite in time. It has no beginning,” he said in a recent episode of Morgan Freeman’s Through the Wormhole.
“You have an infinite number of stars, so the sky would be just completely covered in white,” he added. “Bright, bright, so bright that it would fry you.”
However, the stars are actually sparsely distributed in space with darkness all around, contradicting the infinite theory.
‘Only two things are infinite: the universe and human stupidity; and I’m not sure about the the universe.’—Albert Einstein
So if the universe really is finite, what would it be like?
Jean-Pierre Luminet, a cosmologist at the Paris Observatory, likens the universe to an enormous musical instrument, explaining that the larger a piano, or any other instrument, the greater the range of harmonics that can be heard.
He analyzed vibration ripples in the cosmic microwave backgound and found it is missing the longest wavelengths or “low tones,” supporting the theory of a finite universe.
Based on his research, Luminet believes the perfect shape of the universe is a three-dimensional dodecahedron, ie it has 12 sides like a soccer ball.
Related Articles: Galaxy Rotation Explains Asymmetric Nature of Universe
Tags: astronomy, Nature, Science
This video shows how we actually measure a year on Earth. Since our planet’s orbit around the sun does not follow a perfect circle, it does not return to its starting point in space after one year.
There are different methods for measuring a year.
A sidereal year is measured by observing the position of the sun relative to the stars. When the sun takes a course through the constellations on a path called the ecliptic, and returns to its starting point, one sidereal year has passed.
Another method is the tropical year where the year is measured according to the position of the sun relative to the tilt of the Earth’s axis.
If the sun were to be observed every day at noon, we would realize its position is constantly changing, following a trajectory called an analemma. From these calculations we can determine the equinoxes and solstices throughout the year.
The video ends with a detailed description of the gradual and cyclical changes that influence the length of a year on Earth, such as axial precession and axial tilt.
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