Skip to comments.Discovery that quasars don't show time dilation mystifies astronomers
Posted on 04/12/2010 8:40:43 PM PDT by Lorianne
The phenomenon of time dilation is a strange yet experimentally confirmed effect of relativity theory. One of its implications is that events occurring in distant parts of the universe should appear to occur more slowly than events located closer to us. For example, when observing supernovae, scientists have found that distant explosions seem to fade more slowly than the quickly-fading nearby supernovae.
The effect can be explained because (1) the speed of light is a constant (independent of how fast a light source is moving toward or away from an observer) and (2) the universe is expanding at an accelerating rate, which causes light from distant objects to redshift (i.e. the wavelengths to become longer) in relation to how far away the objects are from observers on Earth. In other words, as space expands, the interval between light pulses also lengthens. Since expansion occurs throughout the universe, it seems that time dilation should be a property of the universe that holds true everywhere, regardless of the specific object or event being observed. However, a new study has found that this doesnt seem to be the case - quasars, it seems, give off light pulses at the same rate no matter their distance from the Earth, without a hint of time dilation.
Astronomer Mike Hawkins from the Royal Observatory in Edinburgh came to this conclusion after looking at nearly 900 quasars over periods of up to 28 years. When comparing the light patterns of quasars located about 6 billion light years from us and those located 10 billion light years away, he was surprised to find that the light signatures of the two samples were exactly the same. If these quasars were like the previously observed supernovae, an observer would expect to see longer, stretched timescales for the distant, stretched high-redshift quasars. But even though the distant quasars were more strongly redshifted than the closer quasars, there was no difference in the time it took the light to reach Earth.
This quasar conundrum doesnt seem to have an obvious explanation, although Hawkins has a few ideas. For some background, quasars are extreme objects in many ways: they are the most luminous and energetic objects known in the universe, and also one of the most distant (and thus, oldest) known objects. Officially called quasi-stellar radio sources, quasars are dense regions surrounding the central supermassive black holes in the centers of massive galaxies. They feed off an accretion disc that surrounds each black hole, which powers the quasars extreme luminosity and makes them visible to Earth.
One of Hawkins possible explanations for quasars lack of time dilation is that light from the quasars is being bent by black holes scattered throughout the universe. These black holes, which may have formed shortly after the big bang, would have a gravitational distortion that affects the time dilation of distant quasars. However, this idea of gravitational microlensing is a controversial suggestion, as it requires that there be enough black holes to account for all of the universes dark matter. As Hawkins explains, most physicists predict that dark matter consists of undiscovered subatomic particles rather than primordial black holes.
Theres also a possibility that the explanation could be even more far-reaching, such as that the universe is not expanding and that the big bang theory is wrong. Or, quasars may not be located at the distances indicated by their redshifts, although this suggestion has previously been discredited. Although these explanations are controversial, Hawkins plans to continue investigating the quasar mystery, and maybe solve a few other problems along the way.
Hawkins paper will be published in an upcoming issue of the Monthly Notices of the Royal Astronomical Society.
More info: http://www3.interscience.wiley.com/journal/123345710/abstract?CRETRY=1&SRETRY=0
Please allow me to wax philosophical and a it theological.
God made a massive and unbelievably complex Universe with rules that are discoverable and consistent. He evolved within us, His Children, brains that can reach to that Universe, and attempt to identify, classify and in the end, harness that Universe and bend it to Man’s will.
But knowing there are rules and jotting them down takes some darn smart people.
This article puts me at the very edge of what I can understand scientifically. And, since I have acrophobia, I don’t want to look down at the cliff face I find myself backed into.
Thanks for posting this, Lorianne — it is of incredible substance.
>>This guy just proved the existence of G-d. Everywhere, all of the time and at the same time. Maybe these are just cracks through which we can peek at Heaven? <<
"One second is defined as 'the duration of 9192631770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom'..."
Now imagine, instead of a vibrating 'caesium 133 atom', we have a beam of light bouncing back and forth between two mirrors within a vertical tube. Now let's say, for the sake of argument, that it takes precisely 'one second' for the light beam to reach the top mirror (tick), reflect off it, reverse and reach the bottom mirror (tock).
Now let's say the light tube, or 'light clock', is resting on a flatbed train car, and on the flatbed is an observer who we will call "Observer A". To Observer A, who is moving along with the train and is therefore 'at rest' with respect to it, the light beam simply travels from the bottom of the tube *vertically* to the top of the tube and then straight back down again. From the relationship, speed equals distance over time, we get time equals distance over speed. So this is then how Observer A defines time (t=distance/speed). Important to note here is that light travels at the SAME SPEED for ALL observers.
Now let's say there is an observer B standing on the embankment alongside the train watching it pass by. From this observer's point of view, or frame of reference, the light beam does NOT simply travel vertically up and down. Rather, it travels on a slanted or diagonal path since the train is in motion, let's say from left to right as Observer B sees it. Now since the light beam travels a diagonal path between tick and tock, again, from OB's stationary point of view, the light beam therefore is traveling a LONGER distance (from OB's perspective). Therefore, since the light beam is traveling a longer distance (from OB's perspective) AND since light travels at the same speed for all observers, the light beam MUST take a longer time to bounce between the two mirrors (tick-tock). Therefore, the two observers (A and B) do NOT agree on what a "second" is.
The mathematical relationship between the two paths is based on the Pythagorean Theorem for right-triangles that many of us used in high school.-ETL
However, when considering velocities, one must also keep the frame of reference fixed.
Which observer is correct in his definition of time?
Neither? Both? or both Neither and both?
Quasars got legs!
There is a very tiny, undiscovered micro black hole residing in my wallet. I saw it once, just a small spot of incredible blackness, in the corner of the money compartment. I felt a sort of morbid fascination as I stared into it. I poked it with my career, and that too disappeared. I don’t look in there anymore.
If the relative velocity between the two frames is constant (i.e., inertial), then the effects are reciprocal and BOTH correctly see the other's clock ticking out time more slowly than their own. However, if a force is involved and one of the frames is accelerating (i.e., changing its rate of speed OR direction), then the effects become real. It takes energy to move ahead in time. Velocity and therefore acceleration are 2-component vectors containing both speed AND direction. Change either the magnitude of the speed or the direction and the frame accelerates.
Gravity is its own independent force (minus mass). Once that is factored out, these simul events work out. It may not be conventional thinking at this point in time, but it will have to be eventually.
Gravity occurs first, coalesces any mass/gas around it. Enough He and H and a gravitational field and - pow - stars. Iron, Silicon, Magnesium, etc... floating around gets crushed in the gravity field and results in our planet. And of course mass itself can cause gravity as well.
If E (energy) can exists outside the equation (E=MC2) then theoretically it can exist minus mass as G alone.
Think outside the thinkers outside the box.
Simply put, the light pulse traces out different paths for each of the two observers. The one riding along with the clock sees it simply move straight up and down, while the observer on the sidelines watching the apparatus moving past him sees it trace out a diagonal, and therefore *longer*, path. Since light travels at the same speed for every observer, the light pulse MUST then take a longer time to travel the longer (diagonal) path (as seen from the point of view of the observer on the sidelines). Or "moving clocks tick more slowly than stationary ones".
There IS no such thing as an inertial reference frame, only approximations to one.
Light is amazing. It travels at the rate of about 6 trillion miles a year for billions of years, never a day off, never gets paid, and never gets tired. You’d think some light rays would say “enough already! what’s the point of all this?” but they don’t.
The following is with respect to the stationary outside observer watching the light clock apparatus move past him from left to right:
When the light pulse leaves the bottom reflector/emitter, the clock is at position 1. When it reaches the upper, it is at position 2. When it returns to the lower, it is at position 3. The movement of the apparatus is left to right with respect to the outside stationary observer.
One theory, of dubious origin, posits that quasar’s are not in fact a natural phenomenon at all, but rather the result of alien civilizations flying planet sized spacecraft about the universe. It is, of course, given for this scenario that the realities of relativistic mechanics require that any serious interstellar mode of travel assume such proportions. Craft moving away from us would then be redshifted (appearing to us as quasars), craft moving toward us would be blueshifted straight into the deep UV region (and be blocked from sight by our atmosphere).
Just something I recalled when reading this article.
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