A still from a video simulation showing what a black hole's shadow might look like. The video was produced by Peter Galison and Chyld King for a short film about the Event Horizon Telescope project. The first image of a black hole will be unveiled at a press conference at 9:00 a.m. EDT on April 10, 2019 (9:00 p.m. Beijing time).
A still from a video simulation showing what a black hole's shadow might look like. The video was produced by Peter Galison and Chyld King for a short film about the Event Horizon Telescope project. The first image of a black hole will be unveiled at a press conference at 9:00 a.m. EDT on April 10, 2019 (9:00 p.m. Beijing time).

Image: © EHT Outreach/YouTube

  Some time ago, the EHT announced that it would hold a press conference on April 10, 2019. The following is part of the EHT’s statement:

  On April 10, 2019, the Event Horizon Telescope (EHT) collaboration will hold simultaneous press conferences in several regions around the world to present its latest research results, together with numerous events organized by researchers and affiliated institutions. The press conferences will take place simultaneously in Brussels (English), Lyngby (Danish), Santiago (Spanish), Shanghai (Chinese), Tokyo (Japanese), Taipei (Chinese), and Washington (English), beginning at 13:00 UTC (21:00 Beijing time).

  The Shanghai Astronomical Observatory of the Chinese Academy of Sciences and Taiwan’s Academia Sinica Institute of Astronomy and Astrophysics subsequently announced that they, too, would host press conferences at their respective locations.

Shanghai Astronomical Observatory, Chinese Academy of Sciences
Shanghai Astronomical Observatory, Chinese Academy of Sciences
Academia Sinica Institute of Astronomy and Astrophysics
Academia Sinica Institute of Astronomy and Astrophysics

  The scientific press conferences scheduled across six countries and regions will begin at 9:00 p.m. Beijing time on April 10. Astronomers are extremely excited because a black hole’s gravitational field is so powerful that not even light can escape. Black holes exert immense gravitational forces on nearby celestial bodies, and observations of those bodies have led scientists to accept their existence widely, yet no one has ever truly “seen” one. Their gravity is strong enough to send stars around them at tremendous speeds. The previously observed object S0-2 completes an orbit in 15.2 years, traveling at nearly 3% of the speed of light—9,000 kilometers per second. That is an extraordinary figure. For comparison, the Solar System takes about 230 million years to orbit the center of the Milky Way and moves at only about 250 kilometers per second.

  The Event Horizon Telescope (EHT) is not one enormous telescope, as one might imagine. It is a network of eight radio telescopes distributed across Hawaii, Arizona, Spain, Mexico, Chile, and Antarctica. In April 2017, the network targeted two giants: Sagittarius A*, the supermassive black hole at the center of the Milky Way, and an even larger black hole in the galaxy M87, 53.5 million light-years away. After nearly two years of processing the data, scientists are preparing to release the first black-hole images this April.

This artist's impression depicts a rapidly spinning supermassive black hole surrounded by an accretion disk. A star has been torn apart by the black hole's tidal forces, and the accretion disk consists largely of the star's remains. Heat generated during accretion produces a gamma-ray burst resembling a supernova explosion.
This artist's impression depicts a rapidly spinning supermassive black hole surrounded by an accretion disk. A star has been torn apart by the black hole's tidal forces, and the accretion disk consists largely of the star's remains. Heat generated during accretion produces a gamma-ray burst resembling a supernova explosion.

Image: © ESO, ESA/Hubble, M. Kornmesser/N. Bartmann

  Black holes are, in fact, extremely difficult to observe. “Finding a black hole is about as difficult as trying to find and observe an orange placed on the Moon from Earth,” said Sheperd Doeleman, director of the Event Horizon Telescope project. Black holes are enormous compared with planets and people, but on the scale of the Milky Way even something apparently huge becomes minuscule, making the event horizon of a black hole difficult to photograph. “The EHT’s target is roughly 10% the size of our Solar System,” astrophysicist Sera Markoff of the University of Amsterdam said during a panel discussion. Doeleman added, “Sagittarius A*, the supermassive black hole at the center of the Milky Way, is only about the size of Mercury’s orbit.” The Milky Way is around 50 billion times larger than Sagittarius A*. If a spacecraft could carry astronomers outside the galaxy, finding this black hole among the Milky Way’s billions of other stars and planets would be an extraordinarily difficult task.

This artist's image depicts a simulation of a black hole's accretion disk, along with simulated images of three possible event-horizon shapes.
This artist's image depicts a simulation of a black hole's accretion disk, along with simulated images of three possible event-horizon shapes.

Image: © ESO/N. Bartmann/A. Broderick/C.K. Chan/D. Psaltis/F. Ozel

  “At the heart of the project, 200 scientists want to answer two questions,” said University of Arizona astronomer and physicist Psaltis. “The first is simple: is it possible to photograph a black hole? Their second question is the important one. Scientists want to know whether Einstein’s theory of black holes is completely correct. A hundred years ago, Einstein told us what the size and shape of a black hole’s horizon should be. If we can place a measuring ‘ruler’ across the horizon, we can test Einstein’s theory of black holes.”

Gargantua, the black hole in the film Interstellar, created by the London visual-effects company Double Negative
Gargantua, the black hole in the film *Interstellar*, created by the London visual-effects company Double Negative.

Image:AF ARCHIVE/ALAMY STOCK PHOTO

  Black holes are often portrayed far more imaginatively. The fictional black hole Gargantua, for example, serves as a plot device for time travel in the film Interstellar. It remains unclear whether the image assembled from EHT data will resemble the film’s intricate CGI creation. Beyond producing an accurate image of a black hole’s horizon, scientists hope the imaging will reveal further details about black-hole theory.

  “Because LIGO—the Laser Interferometer Gravitational-Wave Observatory—has found that the spacetime around black holes closely matches Einstein’s predictions from relativity, I hope the EHT data will pin down the physical details of how gas accretes onto and is ejected from around supermassive black holes,” said Abraham Loeb, professor and chair of astronomy at the Harvard-Smithsonian Center for Astrophysics. “A century after the theory of black holes was formulated mathematically, people are about to see the face of a black hole for the first time. Karl Schwarzschild and Albert Einstein would surely be thrilled if they could see this image.”

Appendix: Live-stream links for the excited (a VPN may be required):

  1. Shanghai (Chinese): (The Shanghai link does not require a VPN. Follow the “Read the original” link at the end of the article to enter the stream.) http://www.xinhuanet.com/politics/ksh/zhibo/201904/3731328_m.html?type=mobile

  2. Taipei (Chinese): https://m.youtube.com/watch?v=_GsTBTenBZY&feature=youtu.be

  3. Washington (English): https://m.youtube.com/c/VideosatNSF/live

  4. Brussels (English): https://m.youtube.com/watch?v=Dr20f19czeE&reload=9

  5. Tokyo (Japanese): https://m.youtube.com/watch?v=_QBQMT5vrJo

References

  1. Space.com:https://www.space.com/event-horizon-telescope-is-trying-to-photograph-black-holes.html

  2. Science:https://www.sciencemag.org/news/2019/04/here-s-what-scientists-think-black-hole-looks

  3. EHT:https://eventhorizontelescope.org/science

  4. SaLon.com:https://www.salon.com/2019/02/03/scientists-are-on-the-verge-of-imaging-a-black-holes-shadow-for-the-first-time/

  5. Official websites: Shanghai Astronomical Observatory, Chinese Academy of Sciences; Academia Sinica Institute of Astronomy and Astrophysics