FAQ

Do you have a black hole image yet? When will real images become available?

The images will become available once the EHT collaboration is confident that the data is fully calibrated and that all procedures have been robustly tested. With the data collected in April 2017, the exciting task of processing and analyzing these data is underway within a number of focused working groups. EHT members are actively working on understanding instrumental effects and formatting the output for imaging and science analyses that will look for the black hole "silhouette". Each of these working groups is vitally important for ultimately reaching the EHT science goals...

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You used eight telescopes for a week-long observation of black holes in April 2017. Which telescopes were used, and was it difficult to get so much observing time on all these telescopes?

We consider ourselves very fortunate that our science is widely viewed as compelling, and that many observatories supported the Event Horizon Telescope observations. The following radio telescope observatories were involved in our 2017 observations: ALMA (Atacama Large Millimeter/Submillimeter Array, Chile, Chajnantur Plateau, http://www.almaobservatory.org), APEX (Atacama Pathfinder Experiment, Chile, Chajnantur Plateau, http://www.apex-telescope.org), IRAM 30m (Institute de RadioAstonomie...

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Are there any stellar-mass black holes near the Solar System and can you detect them by using the EHT?

There are lots of stellar-mass black holes that are much closer to the Solar System than Sgr A* in the Galactic Center. However, the size of a black hole is proportional to its mass, so these stellar-mass black holes look much smaller than the Galactic Center black hole. Even if we can detect some stellar-mass black holes with the EHT, we would not be able to resolve the emission around them on the scale of their event horizon.

What if the black hole shadow is oblate or prolate -- does it mean that there is something wrong with the General Theory of Relativity?

Finding something contrary to our expectations (some of which you may find in our simulations gallery) would certainly be interesting. It would not necessarily mean that the General Theory of Relativity is wrong, but it would imply that we have more physics to understand. Discoveries of gravitational waves from merging black holes by LIGO and collaborators have recently confirmed one of the most fundamental predictions of this theory. Read more about What if the black hole shadow is oblate or prolate -- does it mean that there is something wrong with the General Theory of Relativity?

Will the EHT take razor-sharp images of the event horizon?

Obtaining sharp images of the black hole event horizon is very challenging and the EHT will do its best to produce the sharpest images ever obtained. The quality of the images depends on the arrangement of the telescope array, weather conditions at the telescope sites, as well as blurring of images as the light travels from the black hole toward the Earth. Theoretical simulations, some of which you can find in...

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