Interesting semantics in Scientific American

I'm not sure why physicists and astronomers should change their long standing terminology just because of certain current events in the non-science arena. Neither of the suggested replacements is really adequate to cover the field.

Degenerate matter - Wikipedia
Categoryegenerate stars - Wikipedia
Exotic star - Wikipedia
Compact star - Wikipedia

 

"Two aging starlets" is how Hollywood would describe it.

 

Black holes are physics beyond our existing comprehension.

 

At this stage, there ain't no protons or electrons no mo'. At these pressures and densities, the electrons get compressed into the protons to create more neutrons.

There are several exotic hypothesized stages around the neutron star stage, but none confirmed to exist. This latest LIGO discovery is of objects at least at the neutron star stage, but I believe they haven't yet ruled out denser items between neutron and black hole stage, or a mixed merger between two objects at different stages. But it is clearly not two black holes.

What we can comprehend is that at the black hole stage, our understandings of General Relatively and Quantum Mechanics collide with contradictions. Between those two theories, and our understanding of 'reality', something (eventually) has to give. And of those three items, I won't make any bets against the first two.

... nor can I say much more about this without getting in over my head.

 

Bob,

The sun is so hot (14,000,000 degrees Kelvin) that the electrons tend to dissociate from the nuclei in the Plasma. See:

nuclear - Where do the electrons that are released in the sun go? - Chemistry Stack Exchange

For a discussion as the physics is somewhat outside my experience at about 300 degrees Kelvin.

JeffD

 

Things are so squished inside neutron stars that protons and electrons combine and become neutrons. So they say. Not that I understand it but some quarks seem to go out of existence then. Or become neutrinos. Or something.

Degenerate matter is much more degenerate than anything Hollywood, or larger world of powerful unethical males could cook up.

 

Whatever it is, the process of squishing the protons and electrons is quite spectacular, with ginormous amount of energy and material being thrown off in a 'supernova'.

 

Hope y'all have heard 'sounds' associated with LIGO gravity-wave detection. Fine stuff.

 

I should have noted that the emission of vast quantities of neutrinos in this process was reasonably confirmed by the detection of supernova SN1987A by Kamiokande and other neutrino detectors:

SN 1987A - Wikipedia
Kamioka Observatory - Wikipedia

 

Neutrino and gravity-wave detectors are the most improbable things that actually work.

 

GPS receivers don't have anything close to the positioning accuracy to measure this -- meters or centimeters for GPS, depending on available averaging time, vs fractions of a proton diameter for the gravity signal.

The bandwidth of the detector is also limited by its physical size and the number of interference bounces used along the detector legs. It takes a significant amount of time for the laser signals to travel that path, so they can't detect higher pitched signals. A satellite based system all the way across earth orbit won't be able to hear high enough frequencies to pick up the chirps of the same sized black hole and neutron star mergers that LIGO has captured.

On the other hand, some galaxies formed by mergers have binary supermassive black holes co-orbiting at their centers. When those enormous BHs eventually merge, their chirps will be at too-low frequencies for current LIGO systems to detect. Satellite-based systems will likely be needed to pick up such events. But such systems will likely still be based on lasers, not GPS. And they would not be in low earth orbit, more likely high earth or solar orbit.

 

Michelson-Morley resolves speed of light to 10^-17 precision. Somebody could improve that but maybe not cost effective.

LIGO measures mirror spacing to 3^-19 precision; this is needed because gravity waves to not perturb spacetime very much. In non-technical terms LIGO is effing amazing.

Future, better, earth-based LIGOs seem to have hope for 10x improvement, also lower frequency as fuzzy1 considers. About then they may reach a strong limit from seismic noise.

Going to satellites, I suppose at one of Lagrange points, will reveal a new batch of technical challenges. But wiggle watching is pretty neat stuff.

 

OK, moon has a much lower seismic noise floor than earth. Good. For now, tossing stuff at the moon remains very expensive. Bad.

I imagine moon science will focus elsewhere for a long time. Several suggestions for radio astronomy on far side. High 'radio' noise floor on this planet limits our vision.

==
But consider 'physics of the precise'. somewhere in the 10^-low twenties, spacetime wiggles prevent better assessments of some physical constants by any means. There are many kinds of spacetime wiggles below scale of black holes and neutron stars' traffic accidents. Theoretically known and beyond current experimental veil. 'Locally', Sun/Jupiter orbit around barycenter.

Elsewhere, speculatively, ET performing faster-than-light travel would make spacetime wiggles.

A tribute to LIGO Nobel prize is that it draws our attention to such small details that connect everything to everything else!

==
On this tectonically giggling planet, what physics can be pushed to extremes? High-energy particle collisions and neutrino detections both require large masses. So, those. Other investigations of externalia are finally too subtle for dirt-based physics.

Good on BobW for sending our thoughts in these directions. But the thread title is not very good.

 

i saw what you did there.

 

We live in a galaxy (possibly) along with other technological civilizations. We do what we do. They only do long travel by physics we don't know or by investing in large multi-bio-generational cruisers. Neither have come here to public knowledge.

I suppose that faster than light travel is fiction, that 'others' do exist, and that we'll only know if they send 'radio' our way and if we detect it.

Regard these words as blowing smoke until 'something' gets heard.

 

It turns out that these gravity wave detectors and other gravity measuring instruments might also be useful in quickly gauging the very largest of earthquakes. Though despite the article title, the text suggests that it is too early to know if this might help in early warning systems.

Gravity Signals Could Speedily Warn of Big Quakes and Save Lives - Scientific American