Hubble Confirms The Accelerated Expansion Of The Universe
Astronomers have been studying the results of the biggest survey ever conducted by the Hubble space telescope with an international team of scientists, led by Tim Schrabback of the Leiden Observatory and Ludovic Van Waerbeke of the University of British Columbia. The team has been poring over data covering more than 446,000 galaxies in the hopes to better understand cosmic expansion, using ground-based telescopes to compliment the data. What did they find? Not only is the universe getting larger, but it’s getting larger at an accelerated rate.
The technique being used is called weak lensing, whereby astronomers study distortions to find out more about the characteristics of distant galaxies. The heart of the study has been on dark matter: “Dark energy affects our measurements for two reasons,” the University of Bonn’s Benjamin Joachimi said. “First, when it is present, galaxy clusters grow more slowly, and secondly, it changes the way the Universe expands, leading to more distant — and more efficiently lensed — galaxies. Our analysis is sensitive to both effects.”
The study also calls back to Einstein, according to Martin Kilbinger from the Institut d’Astrophysique de Paris: “Our study also provides an additional confirmation for Einstein’s theory of general relativity, which predicts how the lensing signal depends on redshift.”
As for the Hubble, its survey saw it circle the Earth 600 times, photograph the same area of the universe with a slight overlap 575 times, requiring 1,000 man hours of observation.
This clearer map, according to Harvard’s William High, made all the difference: “Before, most of the studies were done in 2D, like taking a chest X-ray. Our study is more like a 3D reconstruction of the skeleton from a CT scan. On top of that, we are able to watch the skeleton of dark matter mature from the Universe’s youth to the present.”
The Physics Of Space Battles
December 17, 2009 by tcgames · Leave a Comment
Joseph Shoer is a Ph.D. candidate in aerospace engineering, studying how modular spacecraft could be assembled, and hoping that they will be the telescopes and human exploration vehicles of the future, and not for crushing the dreams of Martian colonists.
I had a discussion recently with friends about the various depictions of space combat in science fiction movies, TV shows, and books. We have the fighter-plane engagements of Star Wars, the subdued, two-dimensional naval combat in Star Trek, the Newtonian planes of Battlestar Galactica, the staggeringly furious energy exchanges of the combat wasps in Peter Hamilton’s books, and the use of antimatter rocket engines themselves as weapons in other sci-fi. But suppose we get out there, go terraform Mars, and the Martian colonists actually revolt. Or suppose we encounter hostile aliens. How would space combat actually go?
First, let me point out something that Ender’s Game got right and something it got wrong. What it got right is the essentially three-dimensional nature of space combat, and how that would be fundamentally different from land, sea, and air combat. In principle, yes, your enemy could come at you from any direction at all. In practice, though, the Buggers are going to do no such thing. At least, not until someone invents an FTL drive, and we can actually pop our battle fleets into existence anywhere near our enemies. The marauding space fleets are going to be governed by orbit dynamics – not just of their own ships in orbit around planets and suns, but those planets’ orbits. For the same reason that we have Space Shuttle launch delays, we’ll be able to tell exactly what trajectories our enemies could take between planets: the launch window. At any given point in time, there are only so many routes from here to Mars that will leave our imperialist forces enough fuel and energy to put down the colonists’ revolt. So, it would actually make sense to build space defense platforms in certain orbits, to point high-power radar-reflection surveillance satellites at certain empty reaches of space, or even to mine parts of the void. It also means that strategy is not as hopeless when we finally get to the Bugger homeworld: the enemy ships will be concentrated into certain orbits, leaving some avenues of attack guarded and some open. (Of course, once our ships maneuver towards those unguarded orbits, they will be easily observed – and potentially countered.)
Now, Let’s Talk Technology
Sub Seeks To Explore Deepest Part of the Ocean
June 8, 2009 by tcgames · Leave a Comment
A couple of weeks ago, we brought you news on Slice of SciFi about the Deep Flight Super Falcon vessel. The Falcon is a deep-sea exploration vessel, but it isn’t the only one attempting to explore the last frontier on our planet.
According to BBC News, the Nereus, a robotic sub is being prepped to explore one of the deepest parts of the ocean, the Challenger Deep in the Pacific Ocean. The Challenger Deep is over 11,000 meters (36,089ft) deep and has been visited only twice before by vessels by humans.
The $5m submarine will make the attempt after a series of increasingly deep dives.
“Instead of jumping directly into the deep end of the swimming pool with the vehicle, we’ll probably dip our toe in first,” said Andy Bowen of the Woods Hole Oceanographic Institution (WHOI) and one of the designers of Nereus.
“We’ll work at 1,000m, 4,000m, 8,000m and then take a deep breath and see if we can get to 11,000m.”
The Challenger Deep is the deepest-known part of the ocean, located in the Marianas Trench near the island of Guam in the west Pacific.
It is the deepest abyss on Earth at 11,000m-deep, more than 2km (1.2 miles) deeper than Mount Everest is high. At that depth, pressures reach 1,100 times the pressure at the surface.
Earth-Like Planet Discovered
April 23, 2009 by tcgames · Leave a Comment
Several gigantic gaseous planets have been spotted orbiting distant stars, but Planet Gliese 581 e could be the lightest planet outside our Solar System ever detected. Located 20.5 light years away from us, it’s 1.9 times the mass of Earth, indicating there are probably billions of Earth-sized planets revolving around stars throughout the universe.
The only problem with this planet is that it’s so close to its star, it would be uninhabitable. However, three other planets revolve around that same star, and scientists say one of them, Gliese 581 d, could be covered by a large and deep ocean. It’s situated far enough away from its star to be habitable. The catch with that one: it’s seven times more massive than the earth, which would make human explorers feel awfully sluggish.
These are remarkable discoveries. Now we’re getting somewhere. While none of these newly discovered planets are quite right for human habitation, this is exciting news because it shows the likelihood of spotting a planet that’s very much like our own. Now all we need to do is solve that pesky problem of traveling the speed of light to get to any of these places. At the speed of today’s fastest space probe, to get to Gliese 581 d would take about 350,000 years.
Stephen Hawking Hospitalized, Fighting Serious Infection
April 21, 2009 by tcgames · Leave a Comment
Famed mathematician Stephen Hawking was rushed to a hospital Monday and was seriously ill, Cambridge University said.
The university said Hawking has been fighting a chest infection for several weeks, and was being treated at Addenbrooke’s Hospital in Cambridge, the university city north of London.
"Professor Hawking is very ill," said Gregory Hayman, the university’s head of communications. "He is undergoing tests. He has been unwell for a couple of weeks."
Later in the afternoon, Hayman said Hawking was "now comfortable but will be kept in hospital overnight."
Hawking, 67, gained renown for his work on black holes, and has remained active despite being diagnosed at 21 with ALS, (amyotrophic lateral sclerosis), an incurable degenerative disorder also known as Lou Gehrig’s disease.
For some years, Hawking has been almost entirely paralyzed, and he communicates through an electronic voice synthesizer activated by his fingers.
Hawking was involved in the search for the great goal of physics — a "unified theory" — which would resolve contradictions between Albert Einstein’s General Theory of Relativity, which describes the laws of gravity that govern the motion of large objects like planets, and the Theory of Quantum Mechanics, which deals with the world of subatomic particles.
"A complete, consistent unified theory is only the first step: our goal is a complete understanding of the events around us, and of our own existence," he wrote in his best-selling book, "A Brief History of Time," published in 1988.
In a more accessible sequel "The Universe in a Nutshell," published in 2001, Hawking ventured into concepts like supergravity, naked singularities and the possibility of a universe with 11 dimensions.
He announced last year that he would step down from his post as Lucasian Professor of Mathematics, a title once held by the great 18th-century physicist Isaac Newton. However, the university said Hawking intended to continue working as Emeritus…
Skylon Rocket/Jet Hybrid Is, Scientifically Speaking, Super Cool
February 20, 2009 by tcgames · Leave a Comment
Editor’s Note:Â If you’ve seen ‘When Worlds Collide
The Skylon reusable space plane takes off from an airport runway, burns atmospheric oxygen, switching to liquid oxygen and hydrogen to hit escape velocity and attain orbit. At least, it will in 10 years.
The plane will be designed to carry 12 tons of payload into orbit and return safely, without having wasted $100 million worth of throwaway rocket. The company behind this hybrid shuttle is Reaction Engines, which just got a million euros in funding to prove that its “air breathing” Sabre engine can work.
According to the BBC, the key to this engine is a super-cooler, which takes gasses entering the intake at 1000 degrees celsius, and drops them to -130 degrees C in 1/100th of a second, thanks to “arrays of extremely fine piping.” God knows those rocketeers love their piping.
Though not much more is known about Skylon at this point, it’s safe to say we’ll hear more about it and other non-wasteful spaceships in the future. I just hope they keep that Hotblack-Desiato-meets-Naboo-cruiser look. [BBC News]
