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
Lockheed Martin to Develop Laser Weapons for U.S. Navy Destroyers
Sea Level Rise Continuing To Accelerate Every Year, Study Finds
https://cleantechnica.com/2018/03/01/sea-level-rise-continuing-accelerate-every-year-study-finds
Precise New Measurements From Hubble Confirm the Accelerating Expansion of the Universe. Still No Idea Why It’s Happening
Space Catapult Startup Spinlaunch Has Come Out of Stealth Mode. Space Catapults? Yes Please
Astronomers Believe Type Ia Supernovae Can Explain Why the Universe is Expanding Faster Than Predicted
Here's a great writeup on this week's big Astronomy news, and why it's important.
It also illustrates the challenges astronomers face with respect to ever-increasing demands for radio spectrum.
(Research was funded by the National Science Foundation).
Signal detected from the first stars in the universe, with a hint that dark matter was involved
Jonathan Williams
boosted
Mars Curiosity rover can now drill again, and more like a human! NASA's "McGyvering" is paying off. #CoSoScience http://cnet.co/2oD2HdS
These Researchers Used A Laser To Wirelessly Charge A Smartphone
Research funded by the National Science Foundation
Jonathan Williams
boosted
NASA releases time-lapse of the disappearing Arctic polar ice cap #cososcience https://www.youtube.com/watch?v=Vj1G9gqhkYA&feature=youtu.be
(Blog post by Sabine Hossenfelder)
Shut up and simulate. (In which I try to understand how dark matter forms galaxies, and end up very confused.)
http://backreaction.blogspot.com/2018/02/shut-up-and-simulate-in-which-i-try-to.html
@untelligence But for us, at least, we have to deal with the fact that within the reality of our own universe, it seems nothing can travel faster than light.
@untelligence That is an excellent question!
Physicists disagree over whether multiple universes really even make sense. Some say it's a crutch -- the idea that there are an infinite number of universes, each with different sets of physical laws and constants, was basically invented to make people feel better about the odds, rather than account for actual physical necessity.
The bottom line is, we really don't know.
@untelligence You're right. And if that weren't the case, things would get pretty weird, pretty quickly...
@untelligence Mostly, that's true. But even here, it can sometimes make a difference.
The GPS system, for example, requires daily adjustments for the relativistic effects of gravity. But the relativistic effects of the satellites moving with respect to people on the ground have an impact, too.
If those adjustments weren't made, the system would show growing errors of several miles per day!
Jonathan Williams
boosted
Our universe is expanding and our Hubble Space Telescope has just made the most precise measurements of the expansion rate since it was first calculated nearly a century ago. #CoSoScience http://go.nasa.gov/2CCv9AU
Two observers moving at different constant speeds won't necessarily agree that the same events happen in the same order.
The freaky thing is, they're both right.
Reality warps itself to keep the speed of light the same for all constantly-moving observers.
As an engineer, it sounds like a feedback system. But a closer bet is it's simply written into the contract for anything that exists in our universe.
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