Jonathan Williams
- UMD Astronomy
- https://www.astro.umd.edu/~jonvwill/
NSF Astronomical Sciences/Electromagnetic Spectrum Management · Astrophysicist · Engineer · Posts are my own.
Joined Dec 2017
@JWilliams A clarification to the above: GW170817 did not disprove General Relativity predictions. But it DID do damage to some theories that involved modified gravity. Some such theories predicted gravitational waves would travel much more slowly than light.
@JWilliams And considering the mysteries yet to be solved, "big discoveries" most definitely remain.
/fin
@JWilliams It's an incredibly cool time.
It's been said that the "low-hanging fruit" in astronomy has been picked, and the important things already discovered. The first is kind of true: observatories (gravitational wave and electromagnetic) capable of making these discoveries are not cheap or simple. But you get what you pay for: today's telescopes could detect a half-watt cellphone signal from more than .01 light year away (750 times the distance from the Earth to the sun).
@JWilliams And combined LISA and LIGO/VIRGO observations would have detected the run up to a neutron star merger *months* in advance.
Even more exciting: there's only so far back in time that optical astronomy can go. Gravitational wave observations should let us gather data right back to the Big Bang, and solve some big mysteries.
@JWilliams In fact, with planned upgrades to the NSF-funded LIGO observatories and the VIRGO observatories, we should be able to obtain multi-messenger data from much weaker signals closer to home--in our own solar system.
And that's STILL not the end. the 2020's/2030's should see the launch of the LISA satellites which will be sensitive to gravitational waves of different frequencies than LIGO/VIRGO can detect. LISA should see supermassive black hole mergers.
@JWilliams But I said we're not done, right? Rainer Weiss, who shared the 2017 Nobel Prize in Physics for his work on gravitational wave detection, says that (among other things) astronomers would love to have multi-messenger signals from supernovae, and magnetars (neutron stars with phenomenally powerful magnetic fields, which are another potential source of gamma ray bursts).
And with significant advances in the sensitivity of gravitational wave detectors, it should happen.
@JWilliams We could also put boundaries on the optical signal. when the received light shifted from blue to red over time, it confirmed we were seeing heavy element production.
Since the gravitational wave signal indicated "neutron star merger", we now know with high certainty that such mergers produce a large amount of the heavy elements in the universe--including the stuff that makes up your jewelry.
@JWilliams When the gamma ray signal was received at nearly the same time as the gravitational wave signal, it confirmed important predictions in General Relativity, and disproved others. we now know with great certainty that gravity as a force, and gravitational waves, travel at the speed of light.
We also have a pretty good idea now that merging neutron stars are at least one cause of gamma-ray bursts.
@JWilliams The neutron star merger (GW170817) gave us a wealth of data that we couldn't have acquired without both sources of information. because we knew that the event WAS the merger of two neutron stars, and because we knew basically in what direction to look, optical, radio, and gamma-ray observatories didn't have to start from scratch in their observations.
By now, many of us have heard of gravitational wave detection. Many have even heard about the combined gravitational wave and electromagnetic detection and observation of a neutron star merger last year -- the first of its kind to make use of synergistic data from more than one path of information about an event, and which marked the official birth of "multi-messenger astronomy".
But we're not done. not by a long shot.
Jonathan Williams
boosted
how UK spies hacked a European Ally and got away with it
OK, the conclusions are perhaps a bit ahead of themselves. Still, cool research, with potential quantum computing applications.
Star Wars lightsabers could be REAL after mind-blowing quantum research for LASER swords
(Research funded by the National Science Foundation)
Missing the Paris climate target by just a little means raising the odds of extreme weather by a lot
Silicon Nanostructures Bend Light to Make Faster Photodiodes
The availability of very low power, low cost, on-chip, multi-GHz, ultra-stable direct oscillators, resonators, and waveguides will actually find a multitude of uses.
FinFETs Shimmy to 5G’s Frequencies
(Research funded by #DARPA)
https://spectrum.ieee.org/tech-talk/semiconductors/devices/finfets-shimmy-to-5gs-frequencies
New Horizons Just Took a Record Breaking Image. No Camera Has Ever Taken a Picture From This Far From Earth
Astronomers Discover 95 New Exoplanets Using Kepler
https://scitechdaily.com/astronomers-discover-95-new-exoplanets/
It's #CoSoScience Friday in Geneva, Switzerland! 🌍
New Simulation Provides First Hints of What Supermassive Black Hole Mergers Will Look Like
Jonathan Williams
boosted
A new database is fighting the poor visibility of women in STEM by offering female professionals as speakers, panelists, experts, course leaders and advocates for diversity and equity #CoSoScience https://blogs.scientificamerican.com/voices/how-to-find-a-woman-scientist/
What does it mean for string theory that the LHC has not seen supersymmetric particles?
http://backreaction.blogspot.com/2018/02/what-does-it-mean-for-string-theory.html
Jonathan Williams
- UMD Astronomy
- https://www.astro.umd.edu/~jonvwill/
NSF Astronomical Sciences/Electromagnetic Spectrum Management · Astrophysicist · Engineer · Posts are my own.
Joined Dec 2017