Wednesday, May 23, 2018

Giant black hole is cosmic vacuum cleaner

Science popularists used to go around telling ppl that it is a big myth that a black hole can act as a cosmic vacuum cleaner. The Wikipedia List of common misconceptio used to say so.

The NY Times reports:
Astronomers in Australia now say they have found the hungriest heart in all the cosmos. It is a black hole 20 billion times the mass of the sun eating the equivalent of a star every two days.

The black hole is growing so rapidly, said Christian Wolf, of the Australian National University, who led the team that found it in the depths of time, “that it is probably 10,000 times brighter than the galaxy it lives in.” So bright, that it is dazzling our view and we can’t see the galaxy itself. ...

Black holes are a one-way gate to gravitational oblivion, according to Einstein’s theory of general relativity, but they can only swallow so much, depending on their size; the rest of the matter and energy gets splashed out across space, producing the fireworks popularly known as quasars.
Continue reading the main story

The blaze from material swirling around this newly observed drainpipe into eternity — known officially as SMSS J215728.21-360215.1 — is as luminous as 700 trillion suns, according to Dr. Wolf and his collaborators. If it were at the center of our own galaxy, the Milky Way, it would be 10 times brighter than the moon and bathe the Earth in so many X-rays that life would be impossible.
Based on this, I'd say that it is fair to call a black hole a cosmic vacuum cleaner. No space traveler would want to get anywhere near such a thing.

This is also one of the brightest objects in the universe. Not so black, I guess.

NY Times also reports:
It happens every 405,000 years. The Earth’s orbit gradually changes shape from almost circular to slightly elliptical over a period of 202,500 years, and then starts returning to form over the next 202,500 years — like a metronome swinging side to side.

Right now, we are in an almost perfectly circular orbit around the sun, and soon — within some thousands of years, that is — we will start moving toward the elliptical.

This happens because of the Earth’s gravitational interactions with other planets, especially Jupiter and Venus — Jupiter because it is very large, and Venus because it is very near.
Is this settled science? It seems like it could have far-reaching consequences. Maybe life on Earth was only possible because Earth is stabilized by the Moon, Venus, and Jupiter.


  1. When it comes to space telescopes, we will spend $10 billion a go. As for the most common disease known to man, we can't repair a thing:

    The report shows that oral conditions affect as many as 3.9bn people worldwide -- over half the total population. Untreated tooth decay or cavities in permanent teeth -- also known as dental caries -- was the most common of all 291 major diseases and injuries assessed by the GBD 2010 study, affecting 35 per cent of the world population.

    "There are close to 4bn people in the world who suffer from untreated oral health conditions that cause toothache and prevent them from eating and possibly sleeping properly, which is a disability," comments Professor Marcenes. "This total does not even include small cavities or mild gum diseases, so we are facing serious problems in the population's oral health."

    The GBD 2010 estimated that the disability associated with severe tooth loss was between those reported for moderate heart failure and moderate consequences of stroke.

    Oral conditions accounted for an average health loss of 224 years per 100,000 people (years lived with disability or YLDs) -- more than 25 out of 28 categories of cancer assessed in the GBD 2010 study.

    The study found that the global burden of oral conditions is shifting from severe tooth loss towards severe periodontitis and untreated caries. It found that the global burden of oral diseases increased 20 per cent between 1990 and 2010, while a reduction of 0.5 per cent was observed for all conditions together. This increase was mainly due to population growth and ageing.

    Where is the funding and urgency for this?
    "Moradian-Oldak and her team engineered a string of amino acids that contained only the parts needed for enamel crystal creation. Over seven days, the shorter peptide grew synthetic aprismatic enamel that was two times harder than the softened control enamel. Moradian-Oldak reported the results of the study in a paper recently published in the journal ACS Omega."
    USC: Tooth enamel that regrows?

    I sincerely wish that the people who live off the government doing astronomy (highest paid government profession, the last time I checked) die in a fiery car crash, along with their children. They haven't even planned for asteroids hitting the earth but are zooming into invisible exoplanets. Parasite infection!

    1. Progress?

      "Earlier research shows that ancient hunter-gathers had cavities in at most 14% of their teeth, and some had almost no cavities at all. Then, roughly 10,000 years ago, humans learned to farm. Grain and other carbohydrates took over the plate, making the human mouth a haven for bacteria that destroy tooth enamel. Ancient farmers had cavities in up to 48% of their teeth, leading scientists to assume that a human jaw with lots of cavities probably came from a farming society."

      The article can only challenge this research by giving us an anecdote about sweet acorns. James C. Scott wins this round.