raattgift

16 ms·

91.
Euclid finds complete Einstein Ring in NGC galaxy(euclid-ec.org)
167 points by raattgift 2y ago|45 comments
92.
by raattgift 2y ago
The nonlinearity of gravity is obvious even in the solar system - it was discovered because Mercury's orbit, when described with the linear theory of Newton's universal gravitation, behaved as if there were an additional hidden ma
93.
by raattgift 2y ago
Records (which are of variable size) are already checksummed, and there were checksum-hashes which made it vanishingly unlikely that one could choose two different records with the same (optionally cryptographically strong) checksum-hash.
94.
by raattgift 2y ago
Short bluesky thread with some animations: https://bsky.app/profile/spacetelescope.bsky.social/post/3li... The paper: Yusef-Zadeh et al., Non-stop Variability of Sgr A* using JWST at 2.1 and 4.8 micron Wavel
95.
Webb Reveals Rapid-Fire Light Show from Milky Way's Central Black Hole(webbtelescope.org)
5 points by raattgift 2y ago|1 comments
96.
Einstein Probe catches X-ray odd couple(esa.int)
1 points by raattgift 2y ago|0 comments
97.
Trivial Auto Var Init Experiments (2023)(serge-sans-paille.github.io)
1 points by raattgift 2y ago|0 comments
98.
by raattgift 2y ago
> whoever wrote this ... just doesn't have a lot of exposure to QFT Incredible. https://scholar.google.com/citations?user=19WGkFsAAAAJ&hl=en be sure to check past the first 20 papers or so, like, oh, say his 199
99.
What Hawking Radiation Looks Like as You Fall into a Black Hole(arxiv.org)
1 points by raattgift 2y ago|0 comments
100.
by raattgift 2y ago
It's just substituting gravitational redshift for cosmological redshift; one can also substitute kinematic redshift for cosmological redshift. The redder bits are running slower, which one sees from spectral lines that are reliably ge
101.
by raattgift 2y ago
T CrB is a recurrent nova (RN), not a supernova (SN). There is only a microscopic chance of the white dwarf member undergoing runaway fusion becoming a Type Ia SN. So microscopic it would be truly surprising astrophysically.
102.
Grand Spiral NGC 5643(apod.nasa.gov)
1 points by raattgift 2y ago|0 comments
103.
by raattgift 2y ago
Sean Carroll has a bluesky thread on this: https://bsky.app/profile/seanmcarroll.bsky.social/post/3lec7...
104.
by raattgift 2y ago
It depends on the black hole to neutron star (BH:NS) mass ratio. Neutron star-black hole mergers (NSBH; yes sorry the name is the other way around from the easier way to think about the mass ratio) mergers are relatively rare in our detecto
105.
by raattgift 2y ago
> I don't buy CCC Me neither (to say the least), but my comment was an attempt to fairly characterize CCC in this thread's context. > Is CCC on a positive cosmological constant? AFAIK it's not a requirement of Penrose&#
106.
by raattgift 2y ago
A couple things on conformal cyclic cosmology (CCC) for smooth 3+1 dimensional spacetimes: > it restarts once there's nothing left but energy The "nothing left but energy " part is a requirement that matter (in the broade
107.
by raattgift 2y ago
In the standard cosmology the Integrated Sachs-Wolfe effect captures the redshift/blueshift of distant light sources (up to the Cosmic Microwave Background) as it traverses relatively dense regions and relative voids. https:/&#x2
108.
Surprisingly thick ice on Jupiter's moon Europa complicates hunt for life(science.org)
3 points by raattgift 2y ago|0 comments
109.
by raattgift 2y ago
Among the de Sitter invariant states for massive fields is the Euclidean or Bunch-Davies vacuum, which allows for pair production with separations greater than the horizon distance. Since our universe seems to be marching towards a state h
110.
Internal Ocean Tides (2021)(svs.gsfc.nasa.gov)
32 points by raattgift 2y ago|3 comments
111.
by raattgift 2y ago
SWOT - Surface Water and Ocean Topography - https://swot.jpl.nasa.gov/
112.
Global view of seafloor gravity and bathymetry from one year of SWOT(aviso.altimetry.fr)
2 points by raattgift 2y ago|1 comments
113.
by raattgift 2y ago
Honestly, you have a series of good questions and unfortunately I don't think your other interlocutor is helping. I'll give it a try. This is very much a hand-wave. tl;dr: Boltzman brains (Bb) from energy gradients: a "forml
114.
by raattgift 2y ago
> Schröedinger [sic] Schrödinger or Schroedinger: it is just you on HN << https://duckduckgo.com/?q=%22Schr%C3%B6edinger%22+site%3Anew... > who has used "öe", multiple times. Boltzmann brains have nothin
115.
by raattgift 2y ago
You have the analysis right (incompressibility of phase space), but maybe not the application. Bbs are arguments against the early low-entropy state of the universe being a fluctuation out of thermal equilibrium, and of a future universe fl
116.
by raattgift 2y ago
You seem to have it exactly backwards: we have 200 years of practical evidence in favour of modern fluctuation theory thanks to things like steam turbines. Structure does sponataneously appear in a gas in thermal equilibrium, one can show
117.
by raattgift 2y ago
Probably no physicist thinks that Boltzman brains are a potent thought experiment. BBs are short-hand for a problem in combining cosmology and statistical mechanics in a way in which there is a hierarchy of vastly improbable configurations
118.
by raattgift 2y ago
BHs move in space pretty slowly! Singleton black holes from collapsed stars move in their galaxy about the same as uncollapsed star: on the order of 200 km/s or so (faster towards the middle but still in the disc where motion is roughl
119.
by raattgift 2y ago
> Keep reading to the end I did. In particular I did not miss the whole preceding apparent horizon vs event horizon context of §VIII or the second half of the second column of p. 17, all of which conflicts with your: It hasn't
120.
by raattgift 2y ago
From the very top of the second page of that "One good paper": Can a BH form in a finite time as viewed by a distant observer? (Answer: Yes.) From your comment you appear to believe that preprint supports (emphasis your

More ›