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aries1988 : astronomy   19

How Do You Take a Picture of a Black Hole? With a Telescope as Big as the Earth - The New York Times
near the core, that fog forms a great glowing Frisbee that rotates around a vast dark sphere. This is the supermassive black hole at the core of the Milky Way, the still point of our slowly rotating galaxy. We call it Sagittarius A*, that last bit pronounced “A-star.” The black hole itself is invisible, but it leaves a violent imprint on its environment, pulling surrounding objects into unlikely orbits and annihilating stars and clouds of gas that stray too close.

the inaugural run of the Event Horizon Telescope (E.H.T.), a virtual Earth-size observatory designed to take the first picture of a black hole. The E.H.T. uses a technique known as very long baseline interferometry (V.L.B.I.), in which astronomers at observatories on different continents simultaneously observe the same object, then combine the collected data on a supercomputer. The E.H.T.’s director, Shep Doeleman, a radio astronomer with the Harvard-Smithsonian Center for Astrophysics, likes to call the E.H.T. “the biggest telescope in the history of humanity.” It has the highest resolution of any astronomical instrument ever assembled. It’s sharp enough to read the date on a nickel in Los Angeles from New York, to spot a doughnut on the moon and, more to the point, to take a picture of the black hole at the center of our galaxy — or, at least, its shadow.

The effort to get that picture speaks well of our species: a bunch of people around the world defying international discord and general ascendant stupidity in unified pursuit of a gloriously esoteric goal. And in these dark days, it’s only fitting that the object of this pursuit is the darkest thing imaginable.

The physicist Werner Israel put it better when he described a black hole as “an elemental, self-sustaining gravitational field which has severed all causal connection with the material source that created it, and settled, like a soap bubble, into the simplest configuration consistent with the external constraints.”

what a black hole would look like if illuminated by the glow from the superheated matter swirling around it. He did his calculations by feeding punch cards into a primitive computer. He drew the results by hand. His black-and-white images looked like twisted depictions of a black Saturn, with a ringlike accretion disk warped like taffy.

That this shadow might be visible from Earth depended on an astonishing set of circumstances. Earth’s atmosphere happens to be transparent to the electromagnetic radiation — in this case, certain microwaves — shining from the edge of the black hole, even though it blocks radiation of slightly longer and shorter wavelengths. The interstellar gunk lying between Earth and the galactic center also becomes transparent at those frequencies, as do the clouds of superheated matter just outside the black hole, blocking a view of the event horizon. Later in life, Fulvio Melia compared this alignment to the cosmic accidents that give us total solar eclipses. The moon is just the right size, in just the right orbit, at just the right distance from Earth that now and then it blocks the sun entirely. Fulvio wasn’t religious, but these coincidences were so unlikely that he couldn’t help but feel that the black-hole shadow was meant to be seen. The universe had arranged for humans to see to the nearest exit.

it’s hard to reconcile two conflicting theories if you can’t find something wrong with either one, and quantum theory, like general relativity, has passed every test. As a result, scientists have been looking for ever-more-extreme situations in which to test these theories. That led them to black holes.

To avoid poisoning one another’s minds — so that no one could accidentally nudge another group into seeing a black-hole shadow that wasn’t really there — these groups worked in isolation, making images using different algorithms and techniques, trying hard to discredit anything that looked too sharp, too clean, too likely to be the product of wishful thinking.
telescope  astronomy  scientist  world  project  Physics  law  research  relativity  quantum 
october 2018 by aries1988
What Happens If China Makes First Contact?

Science fiction is sometimes described as a literature of the future, but historical allegory is one of its dominant modes. Isaac Asimov based his Foundation series on classical Rome, and Frank Herbert’s Dune borrows plot points from the past of the Bedouin Arabs. Liu is reluctant to make connections between his books and the real world, but he did tell me that his work is influenced by the history of Earth’s civilizations, “especially the encounters between more technologically advanced civilizations and the original settlers of a place.” One such encounter occurred during the 19th century, when the “Middle Kingdom” of China, around which all of Asia had once revolved, looked out to sea and saw the ships of Europe’s seafaring empires, whose ensuing invasion triggered a loss in status for China comparable to the fall of Rome.

Every so often, a Hans Zimmer bass note would sound, and the glass pane would fill up with the smooth, spaceship-white side of another train, whooshing by in the opposite direction at almost 200 miles an hour.

seti does share some traits with religion. It is motivated by deep human desires for connection and transcendence. It concerns itself with questions about human origins, about the raw creative power of nature, and about our future in this universe—and it does all this at a time when traditional religions have become unpersuasive to many.

China could rightly regard itself as the lone survivor of the great Bronze Age civilizations, a class that included the Babylonians, the Mycenaeans, and even the ancient Egyptians. Western poets came to regard the latter’s ruins as Ozymandian proof that nothing lasted. But China had lasted. Its emperors presided over the planet’s largest complex social organization. They commanded tribute payments from China’s neighbors, whose rulers sent envoys to Beijing to perform a baroque face-to-the-ground bowing ceremony for the emperors’ pleasure.
astronomy  seti  china  alien  chinese  project  state  scientist  scifi  technology  development  2017  future  human  discovery  history  Space  interview 
november 2017 by aries1988
Why Land on the Moon? - The Atlantic
THOUGHTFUL critics, concerned over the allocation of limited national resources, ask whether this is a good way in which to spend funds that might otherwise be used for the betterment of man's lot on the surface of the earth. Could some of the money going into space research be diverted into other programs of public interest -- medical research, education, housing, technical aid to emerging nations -- a variety of projects contributing to the welfare of our society?

But if space money cannot readily be rerouted into other channels, that negative consideration in itself is not a reason for these large expenditures. What are the positive values which we derive from this investment?

The current discussion of these values of the space program has served the United States well in directing its attention to questions of national purpose. But, however we may try to break the program down into its elements and to attempt a detailed balancing of debits and credits, the fact remains that the space effort is greater than the sum of its parts. It is a great adventure and a great enterprise, not only for the United States but for all humanity. We have the power and resources to play a leading role in this effort, and it is inconceivable that we should stand aside.
science  politics  policy  discovery  state  moon  astronomy  nasa  space 
october 2017 by aries1988
To find aliens, we must think of life as we don’t know it | Aeon Ideas

To open our minds, we need to go back to basics and consider the fundamental conditions that are necessary for life. First, it needs some form of energy, such as from volcanic hot springs or hydrothermal vents. That would seem to rule out any planets or moons lacking a strong source of internal heat. Life also needs protection from space radiation, such as an atmospheric ozone layer.

Finally, everything we know about life indicates that it requires some kind of liquid solvent in which chemical interactions can lead to self-replicating molecules. Water is exceptionally effective in that regard. It facilitates making and breaking chemical bonds, assembling proteins or other structural molecules, and – for an actual organism – feeding and getting rid of waste.

Meanwhile, another Saturn moon, Titan, could tell us whether life can arise without liquid water. Titan is dotted with lakes of methane and ethane, filled by a seasonal hydrocarbon rain.

If you think of the spectrum like a set of venetian blinds, there are only a few slats removed.
life  planet  research  astronomy  biology 
september 2017 by aries1988
The Search for 'Earth Proxima'
A short film about a team of scientists and their mission to build a powerful telescope to explore exoplanets.
science  scientist  astronomy  earth  planet  cosmos 
july 2016 by aries1988
Dans le désert d’Atacama, l’Observatoire astronomique de Paranal - RFI
Au Chili, à 1200 km au Nord de Santiago, se trouve le VLT, le plus grand Observatoire astronomique européen, le plus grand Observatoire du monde appartenant à une seule organisation, l’ESO. En plein désert d’Atacama,...
chili  astronomy  scientist  life  desert  reportage 
november 2015 by aries1988
Seeking Stars, Finding Creationism
Galileo knew he would have the Church to contend with after he aimed his telescope at the skies over Padua and found mountains on the moon and more moons…

Opposition to the Mauna Kea observatories, which are run by scientists from 11 countries, has been going on for years and is tied inseparably with lingering hostility over colonization and the United States’ annexation of Hawaii in the 19th century. The new telescope is a pawn in a long, losing game.

It’s bad for science, but good (I suppose) for the Native American groups involved, he wrote in an email. Given that the U.S.A. was founded on two great sins — genocide of Native Americans and slavery of Africans — I think science can afford this act of contrition and reparation.
story  tradition  astronomy  science  indigenous  hawai 
may 2015 by aries1988
What Our Telescopes Couldn't See -
I left the world of professional astronomy some time ago. In the years since, I have often thought of how astronomy is seen as a benign, unbiased science. Its sole function is to increase our understanding of how the universe works: astronomers receive and record, but they do not experiment or perturb. They are not tainted by any application to, say, energy development or military technologies. Astronomy is, essentially, a passive science.

I remember realizing when I was a student that I could make a measurement of an object in the sky, and how extraordinary that felt to me, as if it were a way of reaching out and connecting with something so far away. But maybe I found distant galaxies easier to understand than the people around me, and I wonder if my work became a substitute for any true connection. I still look to the edge of the universe, but I try to remember always to keep one eye focused here on earth.
essay  astro  human  science  society  politics  telescope  astronomy  life  americas 
september 2013 by aries1988

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