EldwinSchrodinger @ What happens when galaxies collide?
After billion years from now, our galaxy is in for a shock. With every hour that passes, the Milky Way gets half a million kilometres closer to another large spiral galaxy called Andromeda, and it is only a matter of time before we collide. Over the course of 3 billion years or so, the galaxies will swing through each other, stretching out long, wispy streams of stars before settling down and merging into one. That much we know.
Yet that picture is far from complete. Lying at the centre of our galaxy is a giant black hole more than 3 million times as massive as the sun. The black hole at the heart of Andromeda is believed to be 10 times the size. What will happen to these supermassive black holes during the encounter is anyone's guess.
Astronomers have recently started to find some clues, though. Most, if not all, galaxies have a supermassive black hole at their centres. Everyone thought that these hungry behemoths simply sat at the heart of their parent galaxies, vacuuming up gas clouds and ripped-apart stars. Now it seems they can go off sightseeing. A black hole can cut loose when two galaxies collide: their central supermassive black holes coalesce into a single object, and this can receive a tremendous kick in the process. Some supermassive black holes travel to the outskirts of their galaxy before returning home, others go into exile for good, catapulted unceremoniously into the lonely deep freeze of intergalactic space.
These new insights could explain some of the most puzzling observations chalked up in outer space. It's all thanks to new ways of modelling the complex distortions of space-time wrought by black holes' awesome gravitational power. Theorists have finally learned how to simulate the merger of two black holes (watch a narrated video of two galaxies merging), and the discoveries are coming thick and fast.
Labels: Cosmology
EldwinSchrodinger @ Astronomers look to quark stars for a fifth dimension
IF THE universe has weird extra-spatial dimensions in parallel to the 3D world we see around us, then billion-dollar particle accelerators may not be the only place to find them.
So say Gergely Gabor Barnaföldi and colleagues at the Research Institute for Particle and Nuclear Physics in Budapest, Hungary, who propose that extra dimensions may show their face in areas of extreme gravity around dense stars. The concept could also solve a 25-year-old puzzle about the origin of mysterious particles emanating from a distant star system.
Some string theories predict that there are many more dimensions than the four we experience: the 3D world plus time. From next year, particle physicists hope to spot these dimensions at the Large Hadron Collider near Geneva, Switzerland.
Instead, Barnaföldi's team looked to outer space for evidence of extra dimensions interacting with matter. They analysed the Cygnus X-3 binary system, in which a normal star orbits a second object, generally thought to be a neutron star.
Objects in Cygnus X-3 are under extreme gravity, which the researchers say would provide the necessary conditions for extra dimensions to affect matter. Moreover, it spews out ultra-high-energy particles as far as Earth, which the team say could have been tweaked by an extra dimension inside the system. Astronomers believe these high-energy particles, dubbed "cygnets", strike our atmosphere and decay into muons. Since 1981, underground detectors on Earth have recorded sporadic showers of muon particles coming from the direction of Cygnus X-3. The cygnets are a puzzle because no known particles could last the 37,000-light-year journey from Cygnus X-3 to Earth without decaying.
Some astrophysicists have speculated that these long-lived cygnets may originate in a quark star - a hypothetical star that may form when neutron stars collapse. If such quark stars contained a large number of "strange" type quarks, they might radiate out long-lived cygnets. The problem is that so many strange quarks in a star would make it collapse into a black hole.
According to Barnaföldi's team, the necessary stability could be provided by a universe-spanning fifth dimension rolled up into tiny "rings". In most places in the universe, this fifth dimension would not affect matter, but under the extreme gravity conditions inside Cygnus X-3 it could cause other types of quark to behave like strange quarks. "If we could watch these quarks, they would seem to travel along our three dimensions more slowly than expected because, at the same time, they have to circle round this invisible curly extra dimension," says team member Peter Levai. "Effectively they behave as strange quarks."
”If we could watch these quarks, they would seem to travel along our three dimensions more slowly than expected
Fridolin Weber, an astrophysicist at San Diego State University, California, likes the proposal. "Cygnus X-3 is perfect for searching for extra dimensions," he says. "It's basically a cosmic particle accelerator." But he adds that more evidence is needed to explain the cygnets' origin. The work will appear in the journal Astronomische Nachrichten.
Extracted from: New Scientist magazineLabels: Elementary Particles
EldwinSchrodinger @ ESA Wants Space Pioneers For 520-Day Mars Experiment
The European Space Agency (ESA) on Tuesday called for applications for one of the most demanding human experiments in space history: a simulated trip to Mars in which six "astronauts" will spend 17 months in an isolation tank on Earth. Their spaceship will comprise a series of interlocked modules in an research institute in Moscow, and once the doors are closed tight, the volunteers will be cut off from all contact with the outside world except by a delayed radio link.
They will face simulated emergencies, daily work routines and experiments, as well as boredom and, no doubt, personal friction from confinement in just 550 cubic metres (19,250 cubic feet), the equivalent of nine truck containers.
Communications with the simulated mission control and loved-ones will take up to 40 minutes, the time that a radio signal takes to cross the void between Earth and a spaceship on Mars. Food will comprise mainly the packaged stuff of the kind eaten aboard the International Space Station (ISS).
The goal is to gain experience about the psychological challenges that a crew will face on a trip to Mars.
Four of the crew will be Russian, and two will come from countries that are members of ESA, agency and Russian officials said at the Paris Air Show in Le Bourget.
In all, 12 European volunteers are needed.
A precursor 105-day study is scheduled to start by mid-2008, possibly followed by another 105-day study, before the full 520-day study begins in late 2008 or early 2009.
Backup for the two volunteers taking part in each of these simulations means that 12 Europeans are needed.
"The selection procedure is similar to that of ESA astronauts, although there will be more emphasis on psychological factors and stress resistance than on physical fitness," ESA said in a press release.
Men and women who think they have the right stuff can download the application form here.
The terrestrial Mars-stronauts will not get much glory for their confinement, nor will they get particularly rich.
They will get paid 120 euros (158 dollars) a day, said Marc Heppener of ESA's Science and Application Division.
Viktor Baranov of Russia's Institute of Biomedical Problems, where the experiment will take place, said his organisation had received about 150 applications, only 19 of which came from women.
"The problem is that it is very difficult to find healthy people for this kind of experiment," he said.
Assuming that Mars and Earth are favourably aligned, with their closest distance of 56 million kilometres (35 million miles), it would take 250 days to get there, 30 days spent on site to conduct experiments and 240 days for the return, said Baranov.
A trip to Mars is not an early prospect. The United States has set plans to return to the Moon by 2018 and later head to Mars, but without setting a date.
The trip is fraught with many technical challenges, many of which are outranked by the question of keeping the crew healthy and sane.
Contributed by: Staff Writers
Le Bourget, France (AFP) June 19, 2007
Labels: Astronomy
EldwinSchrodinger @ LHC to be fully constructed by 2008
LHC which stands for Large Hadron Collider, will be fully constructed by 2008, it will, by then be fully functioning and become the world's largest and highest energy particle accelerator in history.
The collider is contained in a 27 kilometre (17 miles) circumference tunnel located underground at a depth ranging from 50 to 150 metres. The tunnel was formerly used to house the LEP, an electron-positron collider.
LHC might trigger one of several theoretical disasters capable of destroying the Earth or even our entire Universe. These include:
- Creation of a stable Blackhole
- Creation of strange matter that is more stable than ordinary matter
- Creation of magnetic monopoles that could catalyze proton decay
- Triggering a transition into a different quantum mechanical vacuum
Labels: Accelerators
EldwinSchrodinger @ Sky Elevators.
Heard of them? in games, movies etc? if not now you will. if humans were have to travel back and fourth to space with shutters. wouldn't it be rather costly per trip and fuel wastage? with this idea and our current technology its feasible! firstly in recent development of nano technology brings us this very strong micro cables known as carbon nanotube. some of you would wonder. what it is? now here's how it'll look like.
i can say. these guys are strong. and stronger than steel which of course, capable of spanning miles from land to space. the problem is. how to join these nanotubes together to form a 4000mile long cable? now thats the question we scientist would like to find out. =X
but there's something which is bugging me the whole time. how could a nanotube support such great tension at such great heights? furthermore supporting a space station up in space which literally "hangs" from earth's ground. and what device is capable to "holding" the sky elevator in place?
now there setbacks about a space elevator. its vulnerable to bad weather and strong winds. you wont want to stay in a capsule swinging back and fourth wouldn't you? secondly. what if the cable snaps and THAT would be disastrous. now for the good points. its very easy to use and its energy efficient. so If space elevator indeed become a reality, sky elevator can be the easy connection point from the earth to space.
Labels: Technology
EldwinSchrodinger @ The fate of human in the near future.
Be it the mutually assured destruction of the atomic bombs, disputed between countries, natural disasters like the uhh, hurricane Katrina and the tsunami caused my an underwater plate movement, these man-made or natural disasters wouldn't be much of a problem actually. what were more concern would be asteroids which might collide on earth in the near future. remember those movies? Armageddon, Deep Impact? well thats something we'll have to consider it to happen in a near future.
we'll see. out solar system seemed in a rather ordered position, revolving and rotating around the sun. BUT, there's no guarantee those tracks of the planets in the solar system are safe and remain clear. in addition to our solar system, theres lots of stuff on the outside. such as chunks of rocks which we'll call them asteroids. and eventually. they'll bound to collide with planets. sizes do vary. when i say that. they can range from the size of a chicken egg to the size of our own Singapore Kallang stadium! now if a rock of that size were to hit earth. thats extinction for mankind and all living things on earth. an exploding asteroid is as powerful as tons of nuclear bombs.
but unfortunately. we cant be sending a few groups of men to space to blow up a rock. just like the movie, Armageddon. doing so will make the it worst for us. why? there'll be chunks of debris from the rock which will cause a meteor shower on earth. and that doesn't make a difference as all! so how are we gonna do to avoid such disaster? don't forget. it may just be this rock. but there millions and billions and trillions of them in the universe. what can i say then? let fate decides! =)
Labels: Stars And Suns
EldwinSchrodinger @ Particle Accelerators
inside the pipe, particles are accelerated by electric fields. powerful amplifiers provide intense radio waves that are fed into resonating structures, the radio-frequency (RF) cavities. each time the particles traverse an RF cavity, some of the energy of the radio wave is transferred to them and they are accelerated.to make a more effective use of a limited number of RF cavities, accelerator designers can force the particle beam to go through them many times, by curving its trajectory into a closed loop. That is why most accelerators will look roughly circular.curving the beam's path is usually achieved by the magnetic field of dipole magnets. this is because the magnetic force exerted on charged particles is always perpendicular to their velocity. perfect for curving the trajectory! The higher the energy of a particle, the stronger the field that is needed to bend it. This means that, as the maximum magnetic field is limited (to some 2 tesla for conventional magnets, some 10 Tesla for superconducting ones), the more powerful a machine is, the larger it needs to be.
in addition to just curving the beam, it is also necessary to focus it. just like a beam of light, a particle beam diverges if left on its own. focusing the beam allows its width and height to be constrained so that it stays inside the vacuum chamber. this is achieved by quadrupole magnets, which act on the beam of charged particles exactly the same way a lens would act on a beam of light.
Labels: Accelerators
EldwinSchrodinger @ String Theory! An answer to everything?
now a few moments ago i was talking about these doughnuts and stuff. now lets go into string theory since wormholes are possible. well einstein might not have to be right always :P now lets go deeper towards the fabrics of space. if we could shrink down to the size of an atom, a million of a billionth of our normal size, we'll enter the world of quantum mechanics. the laws that can show how atoms behave. its, the world of light and electricity and everything that operates in the smallest of scale! here, the fabrics of space is random, chaotic and violent. like an ocean ripple. rips and tears might be a common place. but will these rips cause a cosmic catastrophe? this is where the power of strings comes in. strings sort of calm the chaos of the quantum world. this strings are like tubes which covers the tears. like a protective shield with profound implications. in fact, strings made it possible for space to rip. which means, space is actually more dynamic and changeable then even our einstein could think of. now lets think. does that mean wormholes are possible? if so wouldn't that be cool if we get to travel from places to places in a second? that means, string theory could be far more complicated than anyone of us could have imagined. oh yes. string theory also suggest that we're surrounded by hidden dimensions: mysterious places other than the 3 dimensional space that we know of! that means we could uh, be just living in a world of another world. or we uh, are living in an atom of an atom! with so many possibilities, we're much baffered by the nature of space and time
Labels: String Theory
EldwinSchrodinger @ Wormholes? are they possible?
Now its time for some imaginations from head. lets take a cup/mug and a doughnut. lets say these are the fabrics of spacetime. and they are similar in a way. that means we can change the shape of the doughnut, into a mug and back again without having to rip it apart! suppose you want to change the shape of this doughnut into a very different shape: a shape with no holes. and the only way to do that is to tear the doughnut. so its shape would be from an "O" to a "U" and then reshape it say to a ball. unfortunately, according to einstein's theory, this doughnut, or we call the fabric of spacetime, this is impossible. its only possible for it to stretch or warp, but it cannot rip. wormholes might have existed in our universe. but we cannot create one over a region to another. in other words, i cant take a wormhole to work! but no. recently this concept has been overseen by another theory called the string theory. which i'll talk about in a few moments.
Labels: String Theory
EldwinSchrodinger @ 28 New Exoplanets Discovered!
Astronomers have discovered 28 new planets outside of our solar system, increasing to 236 the number of known exoplanets, revealing that planets can exist around a broad spectrum of stellar types-from tiny, dim stars to giants.
"We added 12 percent to the total in the last year, and we're very proud of that," said one of the study team members Jason Wright of the University of California at Berkeley. "This provides new planetary systems so that we can study their properties as an ensemble."
The planets are among 37 new objects spotted within the past year. Seven of the objects are failed stars called brown dwarfs, with masses that dwarf the largest, Jupiter-sized planets but too small to sustain the nuclear reactions necessary for stellar ignition.
John Johnson of the University of California at Berkeley and his colleagues presented the findings here today at a meeting of the American Astronomical Society (AAS).
Astronomers don't directly spot extrasolar planets, but rather look for stellar wobbles caused by orbiting planets. The planet's size and distance from the parent star affect how strong or weak of a wobble, and more sophisticated techniques for measuring the stellar wobbles has led to an ever-lengthening list of such outer planets. Now they can detect wobbles of a meter per second compared with the 10-meter limit just 15 years ago.
Planet profiles
One of the exoplanets, orbiting a red M dwarf just 30 light-years from Earth, was discovered two years ago, but recent observations have allowed astronomers to pin down its mass, radius and density. The ice-giant planet circles the star Gliese 436 (GJ 436) and has a radius and density that are surprisingly similar to that of Neptune.
Weighing in at 22.4 Earth-masses, the exoplanet is the first Neptune-sized planet observed to transit a star. The previous record holder, dubbed HD 140926b, weighed in at 100 Earth masses, and Jupiter is 320 Earth masses.
"[Gliese 436b] must be 50 percent rock and about 50 percent water, with perhaps small amounts of hydrogen and helium," said head of the planet-search team Geoffrey Marcy, also of UC Berkeley. "So this planet has the interior structure of a hybrid super-Earth/Neptune, with a rocky core surrounded by a significant amount of water compressed into solid form at high pressures and temperatures."
Its 2.6-day orbit around GJ 436 means the hybrid planet circles very close to its star, just 3 percent of the Sun-Earth distance, and making it a hot Neptune. Unlike most giant planets found with such close ties to their stars, this planet has an eccentric orbit. The elongated orbit suggests the parent star could have another planetary companion with a more distant orbit.
"I'm sure people will immediately follow up and try to measure the atmospheric composition of this planet," Wright said.
GJ 436 is an M star and 70 percent of all stars are considered M-type stars, so finding that these dim stars can support planets could mean a boon for planet hunters.
Bigger is better
At least four of the newly spotted planets belong to multiple-planet systems, supporting the idea that at least 30 percent of all planet-parent stars have more than one planetary companion. Since smaller planets and those outside our solar system are trickier to detect, Wright predicts this percentage will continue to rise as detection methods improve.
And three of the just-discovered planets circle stars that boast masses between 1.6 and 1.9 times that of our Sun. Planets orbiting these so-called A- and F-type stars are typically difficult to detect because the stars rotate fast and have pulsating atmospheres.
Due to their extreme rotational velocities and high temperatures, A and F stars only jitter slightly from orbiting planets and so surveys can only pick up wobbles from super-massive planets and brown dwarfs in short-period orbits around these stars.
Johnson discovered that "retired" A stars, which have nearly burned all of their hydrogen and remain stable for a short stint, have slower rotation rates and are not so hot. That makes it easier for astronomers to measure their planet-caused wobbles.
Unlike planets orbiting M-type stars, these exoplanets tend to orbit at least 0.8 astronomical units (AU) from the parent stars.
For this reason, massive stars are more likely to harbor Jupiter-sized planets than are lower-mass stars, Johnson said. And retired A-type stars are twice as likely to support planets compared with Sun-like stars, which Johnson attributes to the fact that bigger stars start out with more material in their disks to feed planet building.
Labels: Astronomy
