Physics | Universe Today

Playing with black holes is a risky business, especially for a star that is unlucky enough to be orbiting one. Assuming an unfortunate star hasn't already had all of its hydrogen fuel and other component elements stripped from its surface, the powerful tidal forces will have some fun with the doomed stellar body. First the star will be stretched out of shape and then it will be flattened like a pancake. This action will compress the star generating violent internal nuclear explosions, and shockwaves will ripple throughout the tormented stellar plasma. This gives rise to a new type of X-ray burst, revealing the sheer power a black hole's tidal radius has on the smaller binary sibling. Sounds painful…
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How do you catch a WIMP? No, I'm not talking about bullying the weakest kid in class, I'm talking about Weakly Interacting Massive Particles (those WIMPs). Well, it isn't easy. Although they are "massive" by definition, they do not interact with the electromagnetic force (via photons) so they cannot be "seen" and they do not interact with the strong nuclear force, so they cannot be "felt" by atomic nuclei. If we cannot detect WIMPs via these two forces, how can we possibly ever hope to detect them? After all, WIMPs are theorized to be flying through the Earth without hitting anything, they are that weakly interacting. But sometimes, they might collide with atomic nuclei but only if they collide head-on. This is a very rare occurrence, but the Large Underground Xenon (LUX) detector will be buried 4,800 feet (1,463 meters, or nearly a mile) underground in an old South Dakota goldmine and scientists are hopeful that when an unlucky WIMP bumps into a xenon atom, a flash of light will be captured, signifying the first ever experimental evidence of dark matter…
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Filed under: Dark Matter, Physics | 10 Comments »

Solar sails were once thought to belong in the realms of science fiction. Huge canopies of lightweight tin foil catching the solar photon breeze, slowly allowing spacecraft to cruise around our solar system propelled by the small but continuous radiation pressure. Recent years however have shown that solar sail spacecraft could be engineered in reality, and a new solar sail invention from the Finnish Meteorological Institute could push this goal one step closer. Rather than using solar radiation pressure, this new concept makes use of the highly charged particles in the solar wind to give the craft its propulsion. Additionally, through radio wave electron excitation, the system may amplify the solar wind acceleration effects, giving the spacecraft a "boost" function…
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Filed under: Physics, Space Flight | 12 Comments »

Question: Will the Large Hadron Collider Destroy the Earth?

Answer: No.

As you might have heard in the news recently, several people are suing to try and get the Large Hadron Collider project canceled. When it finally comes online, the LHC will be the largest, most powerful particle accelerator ever constructed.

If there's something wrong with it, the LHC might have the power to damage itself, but it can't do anything to the Earth, or the Universe in general.

There are two worries that people have: black holes and strange matter.

One of the goals of the Large Hadron Collider is to simulate microscopic black holes that might have been generated in the first few moments of the Big Bang. Some people are worried that these artificial black holes might get loose, and then consume the Earth from within, eventually moving on to destroy the Solar System.

The physicists are confident that any black holes they create will evaporate almost instantaneously into a shower of particles. In fact, the theories that predict that black holes can be created also predicts that black holes will evaporate. The two concepts go hand in hand.

The other worry is that the Large Hadron Collider will create a theorized material called strangelets. This "strange matter" would then be able to infect other matter, turning the entire planet into a blog of strange matter.

This strange matter is completely theoretical, and once again, the same theories that say it might be produced in the Large Hadron Collider also rule out any risks from it.

One of the most important considerations is the fact that the Moon is struck by high energy cosmic rays that dwarf the power of the Large Hadron Collider. They were likely blasted out of the environment around a supermassive black hole.

These have been raining down on the Moon for billions of years, and so far, it hasn't turned into a black hole or strange matter.

You can read more about the Large Hadron Collider lawsuit here. Or how it might create wormholes, a view into other dimensions, or unparticles.

Filed under: Physics, Questions | 10 Comments »

The light echo of an X-ray flare from the nucleus of a galaxy has been observed. The flare almost certainly originates from a single star being gravitationally ripped apart by a supermassive black hole in the galactic core. As the star was being pulled into the black hole, its material was injected into the black hole accretion disk, causing a sudden burst of radiation. The resulting X-ray flare emission was observed as it hit local stellar gases, producing the light echo. This event gives us a better insight to how stars are eaten by supermassive black holes and provides a method to map the structure of galactic nuclei. Scientists now believe they have observational evidence for the elusive molecular torus that is thought to surround active supermassive black holes.
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Filed under: Black Holes, Chandra, Physics | 3 Comments »

Inflation theory proposes that the universe underwent a period of exponential expansion right after the Big Bang. One of the key predictions of inflation theory is the presence of a particular spectrum of "gravitational radiation"—ripples in the fabric of space-time that are really hard to detect but thought to exist. But a team of researchers has now found that gravitational radiation can be produced by a mechanism other than inflation. So this type of radiation, if eventually detected, won’t provide the conclusive evidence for inflation theory that was once was thought to be a certainty.

"If we see a primordial gravitational wave background, we can no longer say for sure it is due to inflation," said noted astronomer Lawrence Krauss, from Case Western Reserve University.
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Both Pioneer probes are approximately 240,000 miles (386,000 km) closer to the Sun than predicted by calculation. Scientists have been arguing over the cause of this mysterious force for a decade and reasons for the Pioneer anomaly range from the bizarre to the sublime. Is it a simple fuel leak, pushing the probes of course? Is it phantom dark matter dragging them down? Or do the gravity textbooks need to be re-written? Unfortunately there's still no one answer, but some researchers believe there might be a small deviation in the large-scale space-time Einstein described in his famous theory of general relativity. See, I knew there would be a simple explanation…
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Filed under: Physics, Space Exploration | 31 Comments »

So what did exist before the Big Bang? This question would normally belong in the realms of deep philosophical thinking; the laws of physics have no right to probe beyond the Big Bang barrier. There can be no understanding of what was there before. We have no experience, no observational capability and no way of travelling back through it (we can't even calculate it), so how can physicists even begin to think they can answer this question? Well, a new study of Loop Quantum Gravity (LQG) is challenging this view, perhaps there is a way of looking into the pre-Big Bang "universe". And the conclusion? The Big Bang was more of a "Big Bounce", and the pre-bounce universe had the same physics as our universe… just backwards… Confused? I am…
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Filed under: Cosmology, Physics | 50 Comments »

Scientists at Oxford University have developed a method to generate the shortest ever single-photon pulse by removing the interference of quantum entanglement. So how big are these tiny record-breakers? They are 20 microns long (or 0.00002 metres), with a period of 65 femtoseconds (65 millionths of a billionth of a second). This experiment smashes the previous record for the shortest single-photon pulse; the Oxford photon is 50 times shorter. While this sounds pretty cool, what is all the fuss about? How can these tiny electromagnetic wave-particles be of any use? In two words: quantum computing. And in an additional three words: quantum satellite communications…
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Have you ever heard that photons behave like both a particle and a wave and wondered what that meant? It's true. Sometimes light acts like a wave, and other times it behaves like a little particle. It's both. This week we discuss the experiments that demonstrate this, explain how scientists figured it all out in the first place. What does wave/particle duality have to do with astronomy? Well, everything, since light is the only way astronomers can see out into the Universe.

Click here to download the episode

Wave Particle Duality - Show notes and transcript

Or subscribe to: astronomycast.com/podcast.xml with your podcatching software.

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The Large Hadron Collider (LHC) is set to go online in May of this year. This magnificent machine will accelerate particles and collide them at such high energies that scientists expect to make some of the biggest discoveries ever about the very small (exotic sub-atomic particles) and the very large (the structure of the Universe itself).

But not everyone is happy. Particle accelerators have always been the source of controversy; at the end of the day, we can only predict the outcome of the LHC experiments. But what if scientists have overlooked something? What if the theories are wrong? A guy living on the other side of the planet to the LHC believes the world may come to an end and he's begun filing a lawsuit against the completion of the accelerator. The concern? A massive black hole might be created, or vast amounts of antimatter will destroy the Earth. And where's the scientific basis for all this panic? Hmmm… didn't think so…
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Filed under: Earth, Physics | 74 Comments »

In the first few moments of the Universe, enormous amounts of both matter and antimatter were created, and then moments later combined and annihilated generating the energy that drove the expansion of the Universe. But for some reason, there was an infinitesimal amount more matter than antimatter. Everything that we see today was that tiny fraction of matter that remained.

But why? Why was there more matter than antimatter right after the Big Bang? Researchers from the University of Melbourne think they might have an insight.
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Filed under: Cosmology, Physics | 29 Comments »

The idea goes like this: Cosmic rays, originating from outside the Solar System, hit the Earth's atmosphere. In doing so these highly energetic particles create microscopic aerosols. Aerosols collect in the atmosphere and act as nuclei for water droplet formation. Large-scale cloud cover can result from this microscopic interaction. Cloud cover reflects light from the Sun, therefore cooling the Earth. This "global dimming" effect could hold some answers to the global warming debate as it influences the amount of radiation entering the atmosphere. Therefore the flux of cosmic rays is highly dependent on the Sun's magnetic field that varies over the 11-year solar cycle.

If this theory is so, some questions come to mind: Is the Sun's changing magnetic field responsible for the amount of global cloud cover? To what degree does this influence global temperatures? Where does that leave man-made global warming? Two research groups have published their work and, perhaps unsurprisingly, have two different opinions…

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Filed under: Environment, Physics | 29 Comments »

Sending quantum information in the form of qubits (quantum bits) have been successfully carried out for years. Firing indecipherable packets of quantum data (or quantum states) via photons can however degrade the message as the photons travel through the dense atmosphere. Also, the distance of transmitting data is severely hindered by other factors such as the curvature of the Earth. Now, for the first time, Italian scientists have carried out a successful mock single-photon exchange between Earth and a satellite orbiting at an altitude of 1485 km. Although transmission may be restricted here on Earth, the use of satellites will greatly increase the range of such a system, possibly beginning an era of long-distance quantum communication with space.
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Filed under: Physics, Satellites | 3 Comments »

It's one of the biggest questions in all humanity: are we alone in the Universe? Either way, the answer is significant. And so, scientists are searching for intelligence out there. Huge arrays of radio telescopes, like the Allen Array scan the skies for radio broadcasts. And researchers have also proposed that aliens might be using lasers to communicate with us. A Russian researcher is proposing another way that aliens might be communicating with us - with neutrinos.
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Filed under: Astrobiology, Physics | 25 Comments »

One of the most complicated construction projects ever attempted reached a major milestone today. The final large detector element for the ATLAS instrument was lowered into the Large Hadron Collider. And this baby's big. Weighing in at 100 tonnes. When the collider finally comes online, this instrument will measure the cascade of particles generated in proton-proton collisions.
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How many moons does Pluto have? The mini-moons of Pluto, Nix and Hydra, were discovered in 2005 (but named in 2006) during an observation campaign by the Hubble Space Telescope. The discovery of these mini-moons increase the number of natural satellites orbiting Pluto to three (including larger moon Charon). But where did these satellites come from? The current accepted theory on the formation on the large moon, Charon, is much like the theory supporting the creation of Earth's Moon. It is thought that a large impact between two Large Kuiper Belt Objects chipped Charon away from a proto-Pluto, putting the chunk of Pluto mass into orbit. Over the years, tidal forces slowed the pair and Charon was allowed to settle into its present-day orbit. Recent theory suggests that Nix and Hydra are a by product of this collision, merely shattered fragments of the huge impact. But there are problems with this idea. Could Nix and Hydra have come from somewhere other than the Pluto-Charon impact?
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Researchers at St. Andrews University, Scotland, claim to have found a way to simulate an event horizon of a black hole - not through a new cosmic observation technique, and not by a high powered supercomputer… but in the laboratory. Using lasers, a length of optical fiber and depending on some bizarre quantum mechanics, a "singularity" may be created to alter a laser's wavelength, synthesizing the effects of an event horizon. If this experiment can produce an event horizon, the theoretical phenomenon of Hawking Radiation may be tested, perhaps giving Stephen Hawking the best chance yet of winning the Nobel Prize.
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Filed under: Black Holes, Physics | 59 Comments »

The Sun is constantly losing mass. Our closest star is shedding material through the solar wind, coronal mass ejections and by simply generating light. As the burning giant begins a new solar cycle, it continues to lose about 6 billion kilograms (that's approximately 16 Empire State Building's worth) of mass per second. This may seem like a lot, but when compared with the total mass of the Sun (of nearly 2×10³⁰ kilograms), this rate of mass loss is miniscule. However small the mass loss, the mass of the Sun is not constant. So, when using the Astronomical Unit (AU), problems will begin to surface in astronomical calculations as this "universal constant" is based on the mass of the Sun…
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Filed under: Physics, Solar Astronomy | 22 Comments »

As we get closer to the grand opening of the Large Hadron Collider (LHC) near Geneva, Switzerland, it seems the predictions as to what we might get from the high energy particle accelerator are becoming more complex and outlandish. Not only could the LHC generate enough energy to create particles that exist in other dimensions, it may also produce "unparticles", a possible source for dark matter. Now, the energy may be so focused that even the fabric of space-time may be pulled apart to create a wormhole, not to a different place, but a different time. Also, if there are any time travellers out there, we are most likely to see them in a few weeks…
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Filed under: Physics | 86 Comments »

High energy collisions by the nearly-completed Large Hadron Collider (LHC) may be able to generate particles that are sensitive to dimensions beyond our four dimensional space-time. These exotic particles, called Kaluza-Klein gravitons, would be highly sensitive to the geometry of extra-dimensions, giving scientists an idea about what lies beyond our universe. If these particles are detected, and if their characteristics can be measured, then perhaps the extra dimensions predicted by string theory may be proven to exist…
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US researchers have used a new and innovative method to create, trap and study the elusive helium-8 isotope. Helium-8, containing six neutrons and only two protons, is the most neutron rich substance we can create on Earth and until now, we have been unable to accurately characterize it. Through the use of a "laser trap", physicists in the U.S. Department of Energy's Argonne National Laboratory have accurately mapped the distribution of the atom and could help us understand the science behind exotic neutron stars.
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You know this is a burning question on the minds of eight-year olds everywhere: if you threw a boomerang in zero-gravity, would it come back to you? Japanese astronaut Takao Doi plans to test this very premise when he travels to the International Space Station in March 2008.

Doi plans to bring a paper boomerang to the ISS to test whether it will perform the trick of returning to the thrower in zero-gravity. He reportedly decided to test the boomerang at the behest of Yasuhiro Togai, a world boomerang champion from Osaka, Japan. With the announcement that a paper airplane will be launched from the ISS, space is beginning to look like an unruly high school classroom. But these experiments aren't all fun and games, as there are underlying physical principles that can be explored by such simple tests. Read more…

Filed under: Physics, Space Station | 20 Comments »

British scientists are working to build an invisible magnetic "Ion Shield" to be used during missions in space. A minature solar wind has been created in an Oxfordshire laboratory to simulate the highly charged particles emitted from the Sun and a magnetic "bubble" is being conceived to surround future spaceships. The magnetic field should have sufficient deflecting strength to redirect cancer-causing energetic particles away from future astronauts. Useful, especially during the proposed long-haul flights to Mars should the Sun begin launching flares at the wrong time…
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Filed under: Physics, Space Flight | 14 Comments »

What if time disappeared? Yes, it sounds like a silly question - and if the cosmos sticks to the current laws of physics - it's a question we need never ask beyond this article. Writing this article would in itself be a waste of my time if the cosmos was that simple. But I'm hedging my bets and continuing to type, as I believe we have only just scratched the surface of the universal laws of physics; the universe is anything but simple. There may in fact be something to this crazy notion that the nature of the universe could be turned on its head should the fundamental quantity of time be transformed into another dimension of space. An idea like this falls out of the domain of classical thought, and into the realms of "braneworlds", a view that encapsulates the 4-dimensional universe we know and love with superstrings threaded straight through…
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Filed under: Cosmology, Physics | 76 Comments »