May 4, 2011: Einstein was right again. There is a space-time vortex around Earth, and its shape precisely matches the predictions of Einstein's theory of gravity.
Researchers confirmed these points at a press conference today at NASA headquarters where they announced the long-awaited results of Gravity Probe B (GP-B).
"The space-time around Earth appears to be distorted just as general relativity predicts," says Stanford University physicist Francis Everitt, principal investigator of the Gravity Probe B mission.
Quote:
Originally Posted by NASA
"This is an epic result," adds Clifford Will of Washington University in St. Louis. An expert in Einstein's theories, Will chairs an independent panel of the National Research Council set up by NASA in 1998 to monitor and review the results of Gravity Probe B. "One day," he predicts, "this will be written up in textbooks as one of the classic experiments in the history of physics."
Time and space, according to Einstein's theories of relativity, are woven together, forming a four-dimensional fabric called "space-time." The mass of Earth dimples this fabric, much like a heavy person sitting in the middle of a trampoline. Gravity, says Einstein, is simply the motion of objects following the curvaceous lines of the dimple.
If Earth were stationary, that would be the end of the story. But Earth is not stationary. Our planet spins, and the spin should twist the dimple, slightly, pulling it around into a 4-dimensional swirl. This is what GP-B went to space in 2004 to check.
The idea behind the experiment is simple:
Put a spinning gyroscope into orbit around the Earth, with the spin axis pointed toward some distant star as a fixed reference point. Free from external forces, the gyroscope's axis should continue pointing at the star--forever. But if space is twisted, the direction of the gyroscope's axis should drift over time. By noting this change in direction relative to the star, the twists of space-time could be measured.
(...)
For readers who are not experts in relativity: Geodetic precession is the amount of wobble caused by the static mass of the Earth (the dimple in spacetime) and the frame dragging effect is the amount of wobble caused by the spin of the Earth (the twist in spacetime). Both values are in precise accord with Einstein's predictions.
"In the opinion of the committee that I chair, this effort was truly heroic. We were just blown away," says Will.
Interesting stuff.
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I'm not a physicist, so I hope no one jumps on me for this, but from what I understand, the implications of this are that it represents a true understand of the process of einstein's calculations.
Before, the question was whether this theory was an 'end' and not the means (ie. predicting the end result without really understanding what is happening to get to that point.)
Before, general relativity was something accepted as a theory, with some holdouts from the consensus, now it is demonstrably true. Now, physics and math that follow it are building upon the base of something 'true' rather than 'potentially true'.
Again, I am not a physicist, so this may be an inaccurate analogy, but it's the difference between building your house on what you BELIEVE to be a reasonable foundation compared to KNOWING it is a reasonable foundation. When you know, you can more accurately plan the things that go on top of the foundation.
Edit: "Is this wall not plumb because I didn't build the wall correctly, or because the foundation is off slightly? Well, I know the foundation is correct, therefore I must have built the wall incorrectly."
Last edited by Flash Walken; 05-05-2011 at 08:54 AM.
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Before, general relativity was something accepted as a theory, with some holdouts from the consensus, now it is demonstrably true. Now, physics and math that follow it are building upon the base of something 'true' rather than 'potentially true'.
GR has always been "demonstrably true", otherwise it wouldn't have been a theory at all. Every time you use a GPS unit it confirms GR as a theory.
All this does is do some more measurements to further confirm that the theory is an accurate representation of space, time, and gravity with certain parameters, confirm that the frame dragging predicted by GR does in fact occur.
Gravitational waves on the other hand are another prediction of GR that has yet to be confirmed.
True and potentially true are misleading, because we know that GR isn't true for all things. We know of areas where GR is not representative of reality.
Better to say that this experiment further confirms the accuracy of GR.
Quote:
Originally Posted by Flash Walken
Again, I am not a physicist, so this may be an inaccurate analogy, but it's the difference between building your house on what you BELIEVE to be a reasonable foundation compared to KNOWING it is a reasonable foundation. When you know, you can more accurately plan the things that go on top of the foundation.
In science there's no such thing as absolute knowledge, all knowledge is provisional and relative.
And an established theory is far closer to absolute knowledge than it is to belief, because an established theory has already been tested to be a reasonable foundation by being explaining observed phenomenon and having predictions confirmed.
Frame dragging is another prediction by GR that was confirmed.
Hope that helps.
As to the original question of what the implications of the discovery are, practically not a lot since it just further confirms what was already known to be the best description of spacetime and gravity.
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Well they think they have the genetic modification to eradicate the pests that transmit malaria...but, and heres the fun part:
Now that the genetic transport mechanism is sorted out, the big question is exactly what genetic traits the new mutant mosquitoes should pass on.
There are three possible lines of attack, says Crisanti.
The first is to stop the mosquito excreting the parasite when it bites.
The second is to destroy the genes that mosquitoes use to recognize humans to bite.
Crisanti says he knows how to snip out the gene that allows mosquitoes to sniff us out. After that, he says, they will bite animals instead.
The third option is to screw up their reproductive systems so that they produce only males.
Plan to exterminate all Mosquitos withing 10 years! Wasps too!
Even if we remove their ability to recognize humans as source of blood, nature will adapt and they will likely re-evolve that ability within successive generations as human beings are too plentiful and convenient food source to ignore. Maybe a combination of preventing the spread of parasites and also genetically altering their anesthetizing agent and the chemicals that cause the irritation in bites is an answer.
A rocky world orbiting a nearby star has been confirmed as the first planet outside our solar system to meet key requirements for sustaining life, scientists said on Monday. Modelling of planet Gliese 581d shows it has the potential to be warm and wet enough to nurture Earth-like life, they said. It orbits a red dwarf star called Gliese 581, located around 20 light years from Earth, which makes it one of our closest neighbours.
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A rocky world orbiting a nearby star has been confirmed as the first planet outside our solar system to meet key requirements for sustaining life, scientists said on Monday. Modelling of planet Gliese 581d shows it has the potential to be warm and wet enough to nurture Earth-like life, they said. It orbits a red dwarf star called Gliese 581, located around 20 light years from Earth, which makes it one of our closest neighbours.
A spaceship travelling close to light speed would take more than 20 years to get there, while our present rocket technology would take 300,000 years.
Space is big.
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Since it can't hurt to post these again, now that the size of our Universe is being talked about, lets take a gander at the two most mind blowing videos on size in our universe.
__________________ Allskonar fyrir Aumingja!!
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In case you have dumb people posting links to a 2010 story suggesting a cure for cancer has been found and the typical BIG PHARMA doesn't care cause its not profitable enough...
Here's a story on it, recently updated for dumb people on social media sites spreading this.
Dawn, as a mission belonging to NASA’s Discovery Program, delves into the unknown, drives new technology innovations, and achieves what's never been attempted before. In Dawn’s case, it is orbiting one member of the main asteroid belt, Vesta, before heading to gather yet more data at a second, Ceres.
Dawn's goal is to characterize the conditions and processes of the solar system's earliest epoch by investigating in detail two of the largest protoplanets remaining intact since their formations. Ceres and Vesta reside in the extensive zone between Mars and Jupiter together with many other smaller bodies, called the asteroid belt. Each has followed a very different evolutionary path constrained by the diversity of processes that operated during the first few million years of solar system evolution.
Dawn is 810,00 kilometers (500,000 miles) from Vesta today and approaching it at 300 meters per second (670 mph).
Seems slow, but keep in mind it's getting there by matching orbit, not by flying straight there.. orbital mechanics are counter intuitive, if you increase your speed you move out to a larger orbit and lag behind your target, or if you decrease speed you move to a lower orbit and overtake your target. It's very confusing to try and do in a simulator.
And the faster it goes the sooner it would have to turn around and start breaking to slow down enough to be captured and orbit the asteroid, so there's a question of fuel and efficiency and time and all that. Getting there faster requires more propellant, which increases mass, which requires more propellant to accelerate, etc..
And it's 300m/s relative to Vesta, but Vesta is orbiting at 18000m/s so Dawn's already going at close to that speed.
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A new result from astronomers who have spent years peering toward the center of the Milky Way has led to a startling conclusion: there may be billions of Jupiter-sized planets wandering the space between the stars, unbound by the gravity of a parent sun. In fact, there may be nearly twice as many of these free floating planets as there are stars themselves in our galaxy, and they may even outnumber planets orbiting stars!
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<-----Check the Badge bitches. You want some Awesome, you come to me!
