Black holes don't make a big splash

Nov 07, 2013
Merging black holes ripple space and time in this artist's concept. Pulsar-timing arrays -- networks of the pulsing cores of dead stars -- are one strategy for detecting these ripples, or gravitational waves, thought to be generated when two supermassive black holes merge into one. Credit: Swinburne Astronomy Productions

(Phys.org) —Throughout our universe, tucked inside galaxies far, far away, giant black holes are pairing up and merging. As the massive bodies dance around each other in close embraces, they send out gravitational waves that ripple space and time themselves, even as the waves pass right through our planet Earth.

Scientists know these waves, predicted by Albert Einstein's theory of relativity, exist but have yet to directly detect one. In the race to catch the waves, one strategy—called -timing arrays—has reached a milestone not through detecting any , but in revealing new information about the frequency and strength of black hole mergers.

"We expect that many gravitational waves are passing through us all the time, and now we have a better idea of the extent of this background activity," said Sarah Burke-Spolaor, co-author of a new Science paper published Oct. 18, which describes research she contributed to while based at NASA's Jet Propulsion Laboratory in Pasadena, Calif. Burke-Spolaor is now at the California Institute of Technology in Pasadena.

Gravitational waves, if detected, would reveal more information about as well as one of the four fundamental forces of nature: gravity.

The team's inability to detect any gravitational waves in the recent search actually has its own benefits, because it reveals new information about mergers—their frequency, distance from Earth and masses. One theory of black hole growth to hit the theorists' cutting room floors had stated that mergers alone are responsible for black holes gaining mass.

The results come from the Commonwealth Scientific and Industrial Research Organization's (CSIRO) Parkes radio telescope in eastern Australia. The study was jointly led by Ryan Shannon of CSIRO, and Vikram Ravi, of the University of Melbourne and CSIRO.

An image of the Commonwealth Scientific and Industrial Research Organization's (CSIRO) Parkes radio telescope in eastern Australia. Image credit: John Sarkissian

Pulsar-timing arrays are designed to catch the subtle gravitational waves using telescopes on the ground, and spinning stars called pulsars. Pulsars are the burnt-out cores of exploded stars that send out beams of like lighthouse beacons. The timing of the pulsars' rotation is so precise that researchers say they are akin to atomic clocks.

When gravitational waves pass through an array of multiple pulsars, 20 in the case of the new study, they set the pulsars bobbing like buoys. Researchers recording the radio waves from the pulsars can then piece together the background hum of waves.

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"The gravitational waves cause the space between Earth and pulsars to stretch and squeeze," said Burke-Spolaor.

The new study used the Parkes Pulsar Timing Array, which got its start in the 1990s. According to the research team, the array, at its current sensitivity, will be able to detect a gravitational wave within 10 years.

Researchers at JPL are currently developing a similar precision pulsar-timing capability for NASA's Deep Space Network, a system of large dish antennas located around Earth that tracks and communicates with deep-space spacecraft. During gaps in the network's tracking schedules, the antennas can be used to precisely measure the timing of pulsars' radio waves. Because the Deep Space Network's antennas are distributed around the globe, they can see pulsars across the whole sky, which improves sensitivity to gravitational waves.

"Right now, the focus in the pulsar-timing array communities is to develop more sensitive technologies and to establish long-term monitoring programs of a large ensemble of the pulsars," said Walid Majid, the principal investigator of the Deep Space Network pulsar-timing program at JPL. "All the strategies for detecting gravitational waves, including LIGO [Laser Interferometer Gravitational-Wave Observatory], are complementary, since each technique is sensitive to detection of gravitational waves at very different frequencies. While some might characterize this as a race, in the end, the goal is to detect gravitational waves, which will usher in the beginning of gravitational wave astronomy. That is the real exciting part of this whole endeavor."

The ground-based LIGO observatory is based in Louisiana and Washington. It is a joint project of Caltech and the Massachusetts Institute of Technology, Cambridge, Mass., with funding from the National Science Foundation. The European Space Agency is developing the space-based LISA Pathfinder (Laser Interferometer Space Antenna), a proof-of-concept mission for a future space observatory to detect gravitational waves. LIGO, LISA and pulsar-timing arrays would all detect different frequencies of gravitational waves and thus are sensitive to various types of merger events.

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User comments : 19

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mohammadshafiq_khan_1
Nov 07, 2013
This comment has been removed by a moderator.
Sionnach
4 / 5 (8) Nov 07, 2013
I assume that is some sort of joke or parody, but I really can't see the punch line. The first link you posted is not relevant to black holes. That article is about the geographical variations in gravity due to mass density variations of and on extremely small scales. The second link did not seem to take. But the title leaves one scratching their head, a theory of everything shouldn't need revision. Is that punch line?
cantdrive85
1.5 / 5 (25) Nov 07, 2013
"The gravitational waves cause the space between Earth and pulsars to stretch and squeeze," said Burke-Spolaor.

JA!
The punch line is that BH's, GWs, and the BB are enormously expensive works of fiction.
Tuxford
1.5 / 5 (19) Nov 07, 2013
'Scientists know these waves, predicted by Albert Einstein's theory of relativity, exist but have yet to directly detect one.'

Trying to remember the definition of insanity.....
evropej
1.4 / 5 (11) Nov 07, 2013
I love discussions of arm chair scientists, very educational lol.
scottfos
3 / 5 (8) Nov 07, 2013
The very space-time concept, on which theories of relativity are founded, has been mathematically, theoretically & experimentally proved as baseless and openly challenged on the basis of published scientific articles.

no, they haven't. and last time i saw you post here, your "evidence" was a paper written by Barry Setterfield claiming that the speed of light is slowing down, which i researched and found exactly as bogus as i expected and nothing more than a horrible attempt (and even worse, with horrible math!) at proving the earth was 7k years old. he has been debunked and has since tried to merge his pathetic little hypothesis into EU or Plasma (i forget which). i know i'll never convince you to see the evidence, i am only typing this to show others. http://www.cranka...2009.pdf cheers.
IMP-9
3.9 / 5 (7) Nov 07, 2013
Ah, now it's a conspiracy theory. No, some would say we know gravitational waves exist because of the very strong results of the Hulse-Taylor binary and similar systems. Matching the predicted results of the emission of gravitational waves with extreme precision.

This isn't about jobs it's about science. You could either take the result for double pulsars and similar systems and ignore it or you could do a great physics experiment to detect them. Really putting theory to the test. This is science, sometimes it's expensive.
Sionnach
3.2 / 5 (5) Nov 07, 2013
Walter's 1

I know a little about physics, but I'm afraid I didn't understand a word you just wrote. Are you saying that this isn't a valid technique to explore gravitational waves or black holes? As the other person said, it's not about keeping a job, it's about science, and science is a costly endeavor in these times. Also as the other person said, the observations from binary pulsars is very compelling and begs additional examination. It is a fundamental aspect of physics that this work is addressing.
IMP-9
5 / 5 (3) Nov 07, 2013
The other models are simply ignored. This is not scientific approach


It's not possible to test theory at once, so you test the leading model and see where that gets you. Other gravitational theories like MOND are being tested by the same people who make those tests.
Zephir_fan
Nov 07, 2013
This comment has been removed by a moderator.
Fleetfoot
4.2 / 5 (5) Nov 07, 2013
Walter's 1

I know a little about physics, but I'm afraid I didn't understand a word you just wrote.


The account is the latest sock puppet of a notorious troll generally known as "Zephyr", he imagines he can sound knowledgeable by spouting techno-babble but is usually completely clueless. He has occasional lucid posts though so it may be a consortium (or a question of uneven medication).
aroc91
5 / 5 (3) Nov 07, 2013
I wouldn't even call it techno-babble. All he ever does is combines longitudinal, transverse, ripple, wave, density, and water surface, hoping that it'll create something coherent.
Lurker2358
1 / 5 (15) Nov 07, 2013
'Scientists know these waves, predicted by Albert Einstein's theory of relativity, exist but have yet to directly detect one.'

Trying to remember the definition of insanity.....


you noticed that too eh?

They don't "know" a damned thing about Gravitational Waves if they've never detected one.

Right now, they are pure conjecture, and will remain pure conjecture until the "if and when" of discovery.

This is the problem with the present paradigm of physics. They blindly treat a THEORY as though it were the same as objective truth, and they have become so brainwashed that they don't even think about it any more.

I think most interpretations of Relativity will eventually be proven incorrect, including quite a few of Einstein's own assumptions.
Lurker2358
1 / 5 (13) Nov 07, 2013
Zephyr:

You should write a book on AWT. Try to get it published. Worst case scenario is you end up with a science fiction novel and become the next Star Trek.
IMP-9
5 / 5 (3) Nov 07, 2013
Right now, they are pure conjecture, and will remain pure conjecture until the "if and when" of discovery.


If you completely ignore observations of binary pulsars which show orbital decay matching the GR prediction for the emission of gravitational waves then yes it is pure theory. This theory predicted gravitational bending of light and Shapiro delay and gravitational redshift, it's a damn good theory. The discovery isn't an "if" anymore it's a "when", these experiments will either detect them or there is a very big problem. Nobody is blindly accepting theory or tests like this wouldn't be done, we would assume they were there and move on. For someone who thinks relativity will be overturned why would you criticize an attempt to put it to the test?
Code_Warrior
5 / 5 (3) Nov 08, 2013
They don't "know" a damned thing about Gravitational Waves if they've never detected one.

Right now, they are pure conjecture, and will remain pure conjecture until the "if and when" of discovery.

Well, not pure conjecture, they do arise in solutions to GR equations involving the geometry of interest without the need for anything more exotic than black holes orbiting each other. So that's a little bit more than pure conjecture, that's a plausible scenario. As far as what they know, well, they know what the solutions that predict them say, so I'd say they know just a little bit more than nothing. None of this means that gravitational waves exist, mind you, but we're not talking wormholes or other things that require exotic forms of energy, we're talking about black holes in close orbit and merging - something that's entirely plausible as opposed to wormholes and such that are fringe at best.
Code_Warrior
not rated yet Nov 08, 2013
Revised version of this article is available on vixra & General Science Journal in my p

So, you have a science journal in your p. Sounds about right. You should check out the journal I discovered in my last dump. It challenges everything in your p. Unfortunately, I flushed away my chance for science greatness. Sigh....
met a more fishes
1 / 5 (11) Nov 08, 2013
Yeah withholds exist, its just that sometimes two different locations are also the same location
met a more fishes
1 / 5 (11) Nov 08, 2013
*wormholes but anyway I agree with you're point, they are not baseless, they are based upontheories extrapolated from physical phenomena occurring within a relatively (pun) narrow range of both space and time
cantdrive85
1 / 5 (10) Nov 08, 2013
Conspiracy! Conspiracy!...
Fleetfoot
5 / 5 (3) Nov 08, 2013
Well, not pure conjecture, they do arise in solutions to GR equations involving the geometry of interest without the need for anything more exotic than black holes orbiting each other.


Not even as exotic as black holes, Hulse and Taylor observed PSR B1913+16 which is a binary system of two neutron stars and the orbital decay matches what is expected for gravitational wave radiation. GR requires that such systems should radiate so its hard to see how you could modify GR to match all its other confirmations without creating a new theory that also predicted gravitational waves.

Even the Earth orbiting the Sun generates them, they are just far too low in amplitude and frequency to be detectable.