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Comment: Re:Hmmm .... (Score 1) 127

by Hartree (#49180829) Attached to: Physicists Gear Up To Catch a Gravitational Wave

If it shortened all dimensions equally and at the same time everywhere, it would be difficult. But you're looking for a difference in shortening (or lengthening) of one arm of the detector (or the test masses in that arm) relative to the other.

It's a bit waves on the surface of a pond. Sometimes, they expand equally in all directions and form a circular pattern. Sometimes they are different in different directions. This can detect that difference.

Even if the wave is symmetric in all directions, the squeezing/stretching can reach the arms of the detector at different times, just like the points on a circular ripple will reach the short at different times.

Now, of course this is assuming that the waves travel at a certain finite speed (the speed of light as far as we know). If they traveled instantly so the change was everywhere all at once, things would be different.

But, we have pretty solid reasons to believe that they don't travel instantly: That Nobel prize in 1993, I mentioned for example. The amount of energy lost in gravity waves was that of a traveling wave of finite speed, not something that traveled instantly.

Comment: Re:Hmmm .... (Score 1) 127

by Hartree (#49177527) Attached to: Physicists Gear Up To Catch a Gravitational Wave

True. Its more like neutrino astronomy in that respect. But fewer people know about that (and I couldn't come up with a good car analogy to make it Slashdot compatible. ;) ).

Assuming we detect them, being able to do spectroscopy (frequency measurements) and intensity measurements over extended periods to determine rise and fall times of events should be a powerful tool.

Comment: Re:Hmmm .... (Score 2) 127

by Hartree (#49177465) Attached to: Physicists Gear Up To Catch a Gravitational Wave

Thanks for pointing it out. My info was a bit old.

Looks like they put components of H2 in storage and are thinking about using it for LIGO-India. I'd heard of the LIGO-India idea, but hadn't known it would use some of Hanford's equipment.

Another detector at a long distance from the others would greatly improve the ability to localize the source. Let's hope they can get it built and not just have it remain a proposal.

Comment: Re:Hmmm .... (Score 5, Informative) 127

by Hartree (#49176253) Attached to: Physicists Gear Up To Catch a Gravitational Wave

There are two more detectors at the Hanford Washington site. A primary one like at Livingston, and a secondary one that's half the length.

Also, there is an European experiment in Italy, called Virgo. It's currently being upgraded to similar sensitivity to the other 3.

When they are all working, it will allow the detection to not only be verified, but the time of the events at each detector will let them triangulate the location the wave originated from.

We're pretty darn sure of gravitational waves, as a Nobel prize was awarded in 1993 for showing that the slowing of a binary pulsar was just the right amount to account for the gravitational waves it would generate.

These detectors will let us do gravitational wave astronomy much like we do with light and radio waves now.

The huge news would be if they get all of them working with their maximum sensitivity and didn't detect anything. That would mean something was very wrong with their assumptions.

Comment: Word Overloading: (Score 3, Informative) 39

by Hartree (#49159013) Attached to: Pharming Attack Targets Home Router DNS Settings

In the life sciences, "Pharming" is using genetically engineered animals, like goats, to produce proteins or other substances, (especially those with pharmaceutical applications).

Example: Genetically engineered goats that produce spider silk proteins in their milk that can then be extracted from it.


(Warning, possible auto-play)

Comment: Re:What blows my mind (Score 1) 210

by Hartree (#49146973) Attached to: Surgeon: First Human Head Transplant May Be Just Two Years Away

It stems from a very general human response to want those they don't like to die. Even if it means those they love die sooner.

Whenever this subject comes up, there always seem to be comments like: "We can't let this $group-of-bastards escape death!"

That, of course, ignores that $group-of-bastards is usually a small minority compared to the larger number of people who would benefit.

This very argument was made when our now fairly common transplant surgeries were first attempted.

Comment: No left menu on user page: (Score 1) 86

by Hartree (#49144749) Attached to: The Only Constant is Change

And no obvious replacement for it, for some things.

I can get to journal pages, friends, foes, etc by typing in the url, but if someone doesn't already know that, it'll be hard to find. These links were in the left menu on the user page, but they're gone now as well as the left menu on the main page.

(Maybe I'm missing something obvious.)

Comment: Re:Should be damaging (Score 1) 434

by Hartree (#49123705) Attached to: Obama Vetoes Keystone XL Pipeline Bill

"other than Alberta"

Well, Alberta's politics don't fit well with a lot of Canadians. However, it fits quite well with our western states just to the south. So, strictly as a favor to help you out, all us US-ians would be happy to take it off your hands for a small handling fee. We'd even guarantee no pipelines to be built on Canadian soil.


Comment: Re:"Singularity" is a horrible term. (Score 1) 71

by Hartree (#49121675) Attached to: Facebook AI Director Discusses Deep Learning, Hype, and the Singularity

"They really should have come up with something other than the infinitely dense point at the center of a black hole."

It was coined by Vernor Vinge, a sci-fi writer (and professor of CS) for a scifi story. It's a bit much to want absolute accuracy from something he didn't know would become a meme.

"Kill the Wabbit, Kill the Wabbit, Kill the Wabbit!" -- Looney Tunes, "What's Opera Doc?" (1957, Chuck Jones)