Anyone familiar with LISA?

[tanstaafl76]

<br />I did a search on here and didn't find any results, this project sounds very fascinating. However I'm a layman and I don't understand how the three satellites will be able to stay perfectly triangulated with each other when they are so far apart from one another (5 million km); if gets slightly off course, won't the lasers they fire between one another be off course as well and miss?<br /> <div class="Discussion_UserSignature"> </div>

 

[holmec]

Ah yes. The idea was discussed here, a while ago.<br /><br /><br />LISA site<br /><br />Love the idea. <br /><br /><blockquote><font class="small">In reply to:</font><hr /><p>if gets slightly off course, won't the lasers they fire between one another be off course as well and miss? <p><hr /></p></p></blockquote><br /><br />To answer your question, <br />In the site on the page "How Lisa works" it mentions "gravitational reference sensors, micronewton thrusters, and laser interferometry". <br /><br />If nothing disturbs them they naturally stay on course and the slightest movement is measured by their lasers and sensor and adjusted with thrusters. But the project is counting on movement between the parts thus detecting the gravitational wave.<br /><br />Thus it also says, "Because LISA detects gravitational waves by measuring the change in distance between freely floating test masses". <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>

 

[h2ouniverse]

Hi,<br /><br /> Actually there is a precursor mission being developped: LISA PATHFINDER (with some difficulties).<br />http://sci.esa.int/science-e/www/area/index.cfm?fareaid=40<br /><br />Also, there is on ground observation to start soon, with the VIRGO project being in calibration phase.<br />http://virgo.web.lal.in2p3.fr/<br /><br />Regards.

 

[tanstaafl76]

<br />holmec,<br /><br />Thanks for the clarification, I guess I figured there would be other factors that could affect the trajectory of the LISA spacecraft (other than the gravity waves they are trying to detect of course!). What about the gravitational pull of the our moon, would it be too far away to mess with the LISA craft?<br /><br />H2Ouniverse,<br /><br />Yes I've looked at some of the ground observation already underway, there are number of facilities across the world. I think the U.S. experiment, LIGO, which is comprised of two facilities with 4km arm lengths, already is in operation in their first phase, and will be upgrading it to have much more sensitivity within the next couple years. Very interesting stuff how they set these things up, it makes you really think about the fact that there are these gravitational waves washing over us constantly from events that have happened across the universe.<br /> <div class="Discussion_UserSignature"> </div>

 

[MeteorWayne]

There's a screensaver you can run that crunches results from the currently operating Gravitational wave detectors. It's one of 3 I currently have on my computer. It gives lots of details on the experiments as well.<br /><br />Visit Einstein @ Home <br />and<br /> about the project and detectors <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[R1]

...and a video about LISA:<br />http://www.youtube.com/watch?v=DrWwWcA_Hgw <div class="Discussion_UserSignature"> </div>

 

[tanstaafl76]

<br />Wow that artificial voice is annoying, but the video was very informative, thank you!<br /> <div class="Discussion_UserSignature"> </div>