1. Thursday, February 20, 2020

    1. Blog5 – Ill-Fitting Theories – ColinASTR
      • Ill-Fitting Theories
      • his own theory will have to be corrected
      • 100 years.
      • When Bohr exclaimed ‘No reality without observation’, it seemed to put humans back on center stage.
      • If a lot of people dislike a theory, that theory will be tested a ton and might emerge stronger than before if no one can disprove it.
    2. Blog 5 – Ruby's Blog
      • When a person dies, the information content of the electrical firing patterns of their neurons vanishes as this entire electrical system shuts down, and before long, the information content stored chemically and biologically in their synapses begins to disappear as well.
      • when you die all of the memories, knowledge and internal clock is gone
    3. Blog Post 5 – Unsolved Mysteries of the Universe
      • what we know is simply what we know so far.
      • trying to explain the unexplainable.
    4. Blog #5 – Quantum Mechanics – Unsolved Mysteries of the Universe
      • If our universe is a simulation like the Matrix or something crazy like that, physicists/astronomers would be the ones to eventually discover this and try to break us out, like Neo! They’re much cooler when you think of them like that haha.
    5. Blog 5 – Riley Heck ASTR 1270
      • makes this sort of science personal.
      • insanely rare occurrences where this and other bits of matter “woke-up” to create a complex system that is a self-aware human.
  2. Wednesday, February 19, 2020

    1. Blog 5 – Henry Schutte’s ASTRO Blog
      • “I, too, love legos, and I feel that our universe does as well”
      • I too enjoyed the legos symbolism
    2. Henry Schutte’s ASTRO Blog – Just another Edublogs site
      • “So Einstein is saying that gravity is not a thing that lives in spacetime, it’s a manifestation of the nature of spacetime itself.”
      • “I, too, love legos, and I feel that our universe does as well”
    3. Blog 5 – ASTR 1270 – Megan Kane
      • you might hope that there are no physical processes that amplify microscopic weirdness into macroscopic weirdness
    4. Unsolved Mysteries of the Universe – Just another Edublogs site
      • The world is different than what we think and it’s marvelous.
      • Where did WE come from
      • If our universe is a simulation like the Matrix or something crazy like that, physicists/astronomers would be the ones to eventually discover this and try to break us out, like Neo! They’re much cooler when you think of them like that haha.
      • So particle physics is simply rearranging
      • conserved quantities
      • Nothing—they’re just numbers!”
      • Everything is simply information/numbers
      • How is everything the same if the conserved quantities are different?
    5. Unsolved Mysteries of the Universe – Just another Edublogs site
      • What Newton set out to explain definitely, was challenged by Einstein to prove a lack of a definite explanation. This is coupled with the field of Quantum Mechanics which doubles down on this idea of a “lack of constant nature” by asserting the position of an electron is unable to be predicted at any point in time – a state of randomness
      • Physics is driven by puzzles and mysteries
      • trying to explain the unexplainable.
      • we simply don’t know yet
      • that is scientific progress. In order to know more, we must disprove what we already know.
  3. Sunday, February 2, 2020

    1. Bald Black Holes Wearing Wigs | astrobites
      • The No-Hair Theorem is a conjecture about the simplicity of black holes. They are called “bald” to reflect the paucity of information necessary to characterise their spacetime – only three parameters at most are needed.
      • The theorem is formulated to describe isolated black holes.
      • In the words of physicist John Wheeler: “black holes have no hair” (hair being a metaphor here for any messy complicated details).
      • a black hole can be fully characterised by three numbers: mass (M), angular momentum (a) and charge (Q).
      • this theorem means that physical information that enters a black hole will be lost forever
      • it seems to be in direct contradiction to quantum theory in which information is never truly lost! The conflict between the two theories leads to the black hole information paradox.
      • Astrophysical black hole candidates are likely to be electrically neutral
      • the extended No-Hair Theorem is valid even when the black hole is not isolated, e.g. the black hole could be encircled by a matter disk, see Figure 4.
      • A non-isolated black hole is distorted by surrounding matter; these distortions of the mass distribution are described by a sum of “multipole moments”
      • A black hole surrounded by a disk of matter gains two types of hair: (i) distortions to the geometry outside the black hole and (ii) distortions to the geometry of the black hole horizon – these distortions are called horizon multipoles
      • According to the calculation in this paper, all the higher-order horizon multipoles (except for the mass monopole) that arise from the black hole’s intrinsic hair are extinguished at infinity.
      • For example, some alternative theories of gravity admit black hole solutions with hair, so astrophysical observations combined with the extended theorem could help test and constrain alternatives to general relativity.
    2. The feeding habits of supermassive black holes | astrobites
      • One of the most common misconceptions about black holes is that they are invisible
      • gas flowing into a black hole will frictionally heat up to millions of degrees and will become extremely luminous
      • the tidal disruption of an individual star after a close approach to a supermassive black hole.
      • the star is ripped apart by the black hole’s tidal field
      • evolved stars that have left the main sequence can be tidally disrupted by a pass much further away from the black hole
      • a star with a small radius should be swallowed whole before it can be disrupted.
      • As stars evolve towards the end of their life on the main sequence, they tend to expand to many times their main sequence radius
      • it’s much easier to disrupt a more evolved star
      • a star on a rather unfortunate orbit on which it will either by tidally disrupted or swallowed whole by the black hole.
      •  These long-duration disruption events should be observable in the next generation of transient surveys and may be an efficient way to characterize the stellar populations around massive black holes.
      • This observation was special because it was the first time a flare had been caught during the relatively short ramp-up phase thought to be associated with the actual disruption event.
      • Previous observed events were found during the long, slow phase of decreasing luminosity as the black hole slowly eats the remains of the star.
      • transient surveys like the Palomar Transient Factory, and the Large Synoptic Survey Telescope are designed to find luminous but short-lived events like tidal disruption flares, and it is certain that we will soon have a statistical sample of tidal disruptions to study in depth.