Saturday, July 18, 2009
Gravity doesn't make sense? ... hold that thought!
- If gravity were a tiny bit stronger, the universe as we know it would not exist
- From plants to quail, life of all stripes seems to need gravity to work properly
Uh ... so then gravity doesn't make sense because ... why, exactly? Because there wasn't supposed to be a solution to those problems? Why not?
It reminds me a bit of this earlier kvetching about gravity.
Fine tuning is a big problem for these people.
Tuesday, July 14, 2009
Cosmology: Crisis of the month - Gravitation
“The only solution would be to reject Newtońs classical theory of gravitation,” says Pavel Kroupa. “We probably live in a non-Newton universe. If this is true, then our observations could be explained without dark matter.” Such approaches are finding support amongst other research teams in Europe, too.Well, this is a nice change from speculation.
It would not be the first time that Newton’s theory of gravitation had to be modified over the past hundred years. This became necessary in three special cases: when high velocities are involved (through the Special Theory of Relativity), in the proximity of large masses (through the theory of General Relativity), and on sub-atomic scales (through quantum mechanics). The deviations detected in the satellite galaxy data support the hypothesis that in space where extremely weak accelerations predominate, a “modified Newton dynamic” must be adopted. This conclusion has far-reaching consequences for fundamental physics in general, and also for cosmological theories.
Astrophysicist Bob Sanders from the University of Groningen declares: "The authors of this paper make a strong argument. Their result is entirely consistent with the expectations of modified Newtonian dynamics (MOND), but completely opposite to the predictions of the dark matter hypothesis. Rarely is an observational test so definite."
See also: "Time for a New Theory of Gravitation? Satellite Galaxies Challenge Newtonian Model" (ScienceDaily, Apr. 23, 2009) where some of the same cast of characters note the this problem:
The team of scientists looked at the distribution of these satellite dwarf galaxies and discovered they were not where they should be. “There is something odd about their distribution”, explains Professor Kroupa. “They should be uniformly arranged around the Milky Way, but this is not what we found.” The astronomers discovered that the eleven brightest of the dwarf galaxies lie more or less in the same plane - in a kind of disk shape - and that they revolve in the same direction around the Milky Way (in the same way as planets in the Solar System revolve around the Sun).Most interesting, but I'm not clear on what the "crisis" is.
Professor Kroupa and the other physicists believe that this can only be explained if today’s satellite galaxies were created by ancient collisions between young galaxies. Team member and former colleague Dr Manuel Metz, now at the Deutsches Zentrum fuer Luft- and Raumfahrt, also worked on the study. “Fragments from early collisions can form the revolving dwarf galaxies we see today” comments Dr Metz. But he adds that this introduces a paradox. “Calculations suggest that the dwarf satellites cannot contain any dark matter if they were created in this way. But this directly contradicts other evidence. Unless the dark matter is present, the stars in the galaxies are moving around much faster than predicted by Newton’s standard theory of gravitation.”
Oh never mind. By fall, a different crisis.
Monday, July 13, 2009
You never know what'll turn up useful ...
Last year, Dr. Gisin and colleagues at Geneva University described how they had entangled a pair of photons in their lab. They then fired them, along fiber-optic cables of exactly equal length, to two Swiss villages some 11 miles apart. During the journey, when one photon switched to a slightly higher energy level, its twin instantly switched to a slightly lower one. But the sum of the energies stayed constant, proving that the photons remained entangled. More important, the team couldn't detect any time difference in the changes. "If there was any communication, it would have to have been at least 10,000 times the speed of light," says Dr. Gisin. "Because this is such an unlikely speed, the conclusion is there couldn't have been communication and so there is non-locality."Right, so there is no common-sense explanation of quantum mechanics. About the encryption?
Some researchers are using the uncertain state of photons to solve real-world problems. When encrypting sensitive data such as a bank transfer, both the sending party and the receiving party must have the same key. The sender needs the key to hide the message and the receiver to reveal it. Since it isn't always practical to exchange keys in person, the key must be sent electronically, too. This means the key (and the messages) may be intercepted and read by an eavesdropper. An electronic key is usually written in the computer binary code of "ones" and "zeros." Quantum physics permits a more sophisticated approach. The same "ones" and "zeros" can now be encoded by using the properties of photons, like spin. If someone intercepts a photon-based message, the spins change. The receiver then knows the key has been compromised. MagiQ Technologies Inc. of Cambridge, Mass., refreshes its quantum keys as often as 100 times a second during a transmission, making it extremely hard to break. It sells its technology to banks and companies. Dr. Gisin is a founder of ID Quantique SA in Switzerland. The company's similar encryption tool is used by online lottery and poker firms to safely communicate winning numbers and winning hands. Votes cast in a recent Swiss federal election were sent in a similar way.We live in a mysterious world, where uncertainty is better for security than certainty - but at the quantum level only. The person who left his keys stuck in the front door all night is one dumb bunny and can be grateful that most thieves wouldn't expect to get so lucky, which is why he was the first person to discover the problem in the morning.
Multiverse: Getting comfortable with a zillion of everything that is unique?
Greene's transformation is emblematic of a profound change among the majority of physicists. Until recently, many were reluctant to accept this idea of the "multiverse", or were even belligerent towards it. However, recent progress in both cosmology and string theory is bringing about a major shift in thinking. Gone is the grudging acceptance or outright loathing of the multiverse. Instead, physicists are starting to look at ways of working with it, and maybe even trying to prove its existence.Also
If such ventures succeed, our universe will go the way of Earth - from seeming to be the centre of everything to being exposed as just a backwater in a far vaster cosmos. And just as we are unable to deduce certain aspects of Earth from first principles - such as its radius or distance from the sun - we will have to accept that some things about our universe are a random accident, inexplicable except in the context of the multiverse.
However, if our universe is part of a multiverse then we can ascribe the value of the cosmological constant to an accident. The same goes for other aspects of our universe, such as the mass of the electron. The idea is simply that each universe's laws of physics and fundamental constants are randomly determined, and we just happen to live in one where these are suited for life. "If not for the multiverse, you would have these unsolved problems at every corner," says Linde.
Let's see. We don't need to prove fine tuning. It's just there. But there's no evidence for the multiverse; it is an attractive idea because it makes our current cosmological values and fine tuning appear random. I love this line: " ... starting to look at ways of working with it, and maybe even trying to prove its existence".
Question: How fit are people in this state of mind to evaluate what they are seeing?
Podcast in the intelligent design controversy: origin of life
Click here to listen.
On this episode of ID the Future, Casey Luskin interviews Baylor University chemist Dr. Charles Garner on new findings in origin of life research and the plausibility of the chemical origin of life scenario. Listen in as Dr. Garner shows the speculation and imagination materialists employ to explain the origin of life.
For more information, read some of Dr. Garner's comments here at Evolution News & Views.
Those Evil Discos - eviller and eviller
Sunday, June 28, 2009
Origin of life: This time it's salt water
These salty ice grains suggest that the interior of the moon may have liquid water that is washing salty minerals out of rock into a subterranean sea.For way more origin of life stories, go here.
The scientists write that the presence of alkaline salt water, along with the organic compounds and thermal energy that have been observed at the south pole, "could provide an environment well suited for the formation of life precursors."
Friday, June 26, 2009
Cosmology: Who really cares how it washes out at the end?
At the Canadian Science Writers’ Association convention in Sudbury, Ontario, our Sunday dinner speaker was American theoretical physicist Lawrence Krauss of Arizona State University, who presented sample clips from famous sci-fi films. And a whole lot more.
Would you be astonished to learn that the films portray implausible or impossible physics? No?
Filmmakers value audience numbers more than atomic numbers. H
is clips entertained, but did not surprise:However, his talk frequently targeted religion and politics: although he professed to respect theists, he offered snarky asides suggesting that fear of science is growing in Canada (because it might damage religion), adding, "In many ways I hope it does, but it wasn't designed to do that."
Dr. Krauss also told the assembled science communicators that in many key science controversies, there is only one side and journalists confuse matters by seeking out both sides.Not so. New discoveries in science often result from minor, not major, deviations from an expected result.
Read more here.
