Moon Measurements Might Explain Away Dark Energy

[zavvy]

<b>Moon Measurements Might Explain Away Dark Energy</b><br /><br />LINK<br /><br />Plans to trace the Moon's orbit with extraordinary new accuracy could reveal kinks in Einstein's theory of gravity and help explain the mysterious accelerating expansion of the universe, says a US researcher.<br /><br />The acceleration cannot be explained by known forces in the Universe. To account for the behaviour, cosmologists have introduced the concept of a new, as yet unseen, force - dark energy.<br /><br />But Gia Dvali, of New York University, US, believes there could be another explanation. He thinks the accelerating expansion might be caused by unexpected properties of gravity, which are only seen over very large distances. Taking inspiration from string theory, which proposes the existence of several extra dimensions, Dvali, and NYU colleagues Gregory Gabadadze and Massimo Porrati, suggests that gravity may leak into an extra dimension on this large scale.<br /><br />"The accelerated universe can be a window of opportunity for understanding the most fundamental aspects of gravitation, and may signal the modification of standard laws of gravity at very large distances," Dvali told an audience at the American Association for the Advancement of Science meeting in Washington, DC, US.<br /><br />Millimetre accuracy<br />The scheme to measure the Moon's orbit involves firing a laser beam at mirrors left on the surface by the Apollo 11 astronauts and measuring the time it takes for photons to return. This makes it possible to trace the lunar orbit and, so far, astronomers have used the technique to track it with an accuracy of a few centimetres.<br /><br />Now, Tom Murphy, Chris Stubbs and Eric Adelberger at the University of Washington in Seattle, US, plan to use more precise laser equipment to measure the Moon's path to just a few millimetres. At this scale, Dvali's theory predicts that subtle deviations in the Moon'

 

[qzzq]

Interesting, but the last sentence kind of says it all. I'm curious what the laser measurements of the lunar orbit will bring forth though. <div class="Discussion_UserSignature"> <p> </p><p>***</p> </div>

 

[Saiph]

find something that reacts very differently on the scale of the 4th dimension, but as we normally percieve it in the 3rd.<br /><br /> <div class="Discussion_UserSignature"> <p align="center"><font color="#c0c0c0"><br /></font></p><p align="center"><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">----</font></em></font><font color="#666699">SaiphMOD@gmail.com </font><font color="#999999"><em><font size="1">-------------------</font></em></font></p><p><font color="#999999"><em><font size="1">"This is my Timey Wimey Detector.  Goes "bing" when there's stuff.  It also fries eggs at 30 paces, wether you want it to or not actually.  I've learned to stay away from hens: It's not pretty when they blow" -- </font></em></font><font size="1" color="#999999">The Tenth Doctor, "Blink"</font></p> </div>

 

[thalion]

Measurements of the Moon's orbit to that kind of precision might have some other benefits--it might be sensitive enough to detect perturbations from say, the largest asteroids in the asteroid belt, and thus help refine their mass. I'm just grasping at straws here, but I'm almost sure it could help studies of solar system and n-body dynamics.

 

[jmilsom]

Interesting. Anything to shed light on dark matter! I just read the following quote from Ben Moore at the University of Durham:<br /><font color="yellow">"There have been about 10,000 papers written on this topic at a cost of more than a billion dollars, and we still know almost nothing about the nature of dark matter." </font><br /><br />BTW I like your idea kadetken! <div class="Discussion_UserSignature"> </div>