Arun Jiwa @ 05-06-2008
The June 2008 issue of Scientific American sets out to answer a very perplexing question:
Why does time only move forward?
To find the answer, according to Sci-Am and Mr. Sean M. Carroll, we have to start looking at a very unlikely place:
To account for it, we have to delve into the prehistory of the universe, to a time before the big bang. Our universe may be part of a much larger multiverse, which as a whole is time-symmetric. Time may run backward in other universes.
The article is filled with high-end physics and a bit of science jargon, but Mr. Caroll puts uses neat little analogies to explain difficult concepts:
The asymmetry of time, the arrow that points from past to future, plays an unmistakable role in our everyday lives: it accounts for why we cannot turn an omelet into an egg, why ice cubes never spontaneously unmelt in a glass of water, and why we remember the past but not the future. And the origin of the asymmetry we experience can be traced…back to the orderliness of the universe near the big bang. Every time you break an egg, you are doing observational cosmology.
All in all, it’s a very interesting article and well worth a read. Some of the concepts used in the article are highly science fictional and are prime idea fodder for stories about multiverses and time travel. In fact, for those who’ve read River of Gods, may recognize the inspiration for ideas in that novel presented in this article. [image by gadl]
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Tomas Martin @ 10-04-2008
A mix of two stories about completely different types of Black Holes today. First, researchers at the Rochester Institute of Technology found that interactions between three black holes should produce gravitational waves that detectors like LISA or LIGO could detect within the next ten years. Gravitational Waves are ‘ripples’ in Space-Time caused by massive objects and events and could tell us a great deal about the big bang.
Another kind of black hole in the news is the ‘internet black hole’. Researchers for the Hubble internet project found distinct pathways on the internet where data was lost for unexplainable reasons. The project, which you can see the results of at their website, was intentionally named after the famous astronomer and telescope. The researchers say they are performing ‘internet astronomy’, looking for events in the cosmos of data that is the internet.
[image by M Campanelli/L Carlos/Y Zlochower/H-P Bischof, that plus space story via New Scientist, internet story via TG Daily]
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Tomas Martin @ 11-03-2008
Tomas Martin @ 07-03-2008
The Large Binocular Telescope in Arizona has ‘opened its eyes’ for the first time, marking one of the first in a new wave of high-tech astronomical devices to come online. The LBT combines two 8m mirrors working in tandem to take pictures of the sky in a wide range of wavelengths at resolutions higher than that of Hubble.
Another couple of new telescopes, Herschel and Planck, will come online this year following their launch into space in April. Laser Interferometer LISA, which measures the bending of space time, has been given the go ahead but won’t be ready for a decade. A spate of advanced telescopes are in planning and construction, taking advantage of the computer advances of the last decade to give more accurate and detailed pictures of the sky than ever before.
[story and image via BBC]
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Tomas Martin @ 22-12-2007
If you’ve watched Deep Impact and Armageddon a hundred times and still want to know what a real asteroid impact would look like, mark January 30th 2008 on your calenders. On that date, the path of Asteroid 2007 WD5 passes perilously close to our neighbour Mars and may or may not hit it.
The NEO (near-earth object) was found in November and marked because it also passes close to Earth. Analysis of its path say there’s a 1 in 75 chance the 50m rock will impact on the red planet, causing a crater up to half a mile wide.
[via Chris Mckitterick, image by NASA]
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Tomas Martin @ 14-12-2007
On Wednesday I talked about reionisation and how many of the new telescopes being designed are to study this side of astronomy. But what exactly does this mean? Well, ionisation just means that the electrons of an atom are separated from the protons and neutrons. This usually requires a lot of energy, especially if it occurs over a large area. When the universe began after the big bang (the far left of the picture), everything was close together and extremely hot. For a while even the quarks that make up protons and neutrons were independent of each other. Over time the universe grew and the temperature decreased. Quarks recombined into particles, electrons recombined with protons, leaving us with mostly neutral hydrogen, all across the universe.
Now, astronomers can’t see much from neutral hydrogen. It’s too cool to emit much EM-radiation as light, infra red or radio waves that telescopes can pick up. Today, however, we see lots of radiation - from stars, galaxies, black holes, quasars and ionised gas. If the universe was neutral 12 billion years ago, what caused it to reionise? Probably, the first stars caused this change. Over huge periods of time tiny variations in the density of the universe caused the hydrogen to collapse into stars, whose light then ionised the regions around them. By studying the ‘bubbles’ of ionisation so long ago we can work out why the universe has the structure we see today.
Astronomers have never seen that far back before in the key Radio and Infrared regions. The telescopes of the last fifty years just don’t have the power, as Scotty might say. The further back through time you want to look, the further the light has to travel and the fainter the signal. With the advances in computer technology over the last twenty years, we can finally start building equipment capable of seeing those first stars and galaxies. If people are interested, I’ll post the occasional update on how telescopes like JWST and SKA are progressing.
[photo by Nasa's WMAP team via JSWT Science Case]
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Tomas Martin @ 12-12-2007
As astronomers look further back in time, they need more powerful, higher resolution instruments. As well as the search for extrasolar planets, one of the key areas the new technology will be looking at is the epoch of reionisation, some one billion years after the big bang. 400,000 years after the big bang, the universe cooled enough to become opaque, so that very little light was being emitted for us to observe. Later the universe began to change and objects like stars and galaxies formed. The heat from these first objects began ionising the neutral gas of the universe, creating more stars and galaxies in bubbles of hotter regions that eventually spread to form the reionised universe we see today.
Some of the designs for new telescopes are incredible. The picture shows the E-ELT, one of the new designs of Extremely Large Telescopes (anything over 20m in diameter). The small white shape in the bottom left is a car! The awesome James Webb Space Telescope will launch in 2013 to replace the Hubble Telescope. Its mirror and tennis court-sized sunshield unfold in space once it reaches its home orbiting L2, some 1.5 Million km from Earth. ALMA, LOFAR and SKA will links tens or even thousands of smaller radio telescopes together as one massive array, stretching out across continents. The next decade will truly be a revolution in the devices astronomers use to study the sky.
[This is a version of a talk I gave as part of my masters course at Bristol University last week]
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Tomas Martin @ 10-10-2007
Last week here on Futurismic there were some great comments over the future of space seen from a resource rather than an expedition point of view. I mentioned in my post my hope that asteroids may in future be a good source of precious metals such as platinum. Today I stumbled across an example of how that may be done. Aside from the cheesy music and voiceover, this video from Space.Com shows Nasa planning of how to utilise the new Orion Moon landers to travel to Asteroids passing near to Earth’s orbit. By combining this style of approach with a few unmanned surveys of the composition of the NEO (near earth object), it may be possible to start harvesting precious metals that even a few tons would greatly increase current levels.
[via chris mckitterick, image by Don Eastwood]
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