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Creation of the Event Horizon Telescope (EHT)


About the EHT

A long standing goal in astrophysics is to directly observe the immediate environment of a black hole with angular resolution comparable to the event horizon. Such observations could lead to images of strong gravity effects that are expected near a black hole, and to the direct detection of dynamics near the black hole as matter orbits at near light speeds. This capability would open a new window on the study of general relativity in the strong field regime, accretion and outflow processes at the edge of a black hole, the existence of event horizons, and fundamental black hole physics.

The EHT is an international collaboration that has formed to continue the steady long-term progress on improving the capability of Very Long Baseline Interferometry (VLBI) at short wavelengths in pursuit of this goal. This technique of linking radio dishes across the globe to create an Earth-sized interferometer, has been used to measure the size of the emission regions of the two supermassive black holes with the largest apparent event horizons: SgrA* at the center of the Milky Way and M87 in the center of the Virgo A galaxy. In both cases, the sizes match that of the predicted silhouette caused by the extreme lensing of light by the black hole. Addition of key millimeter and submillimeter wavelength facilities at high altitude sites has now opened the possibility of imaging such features and sensing the dynamic evolution of black hole accretion. The EHT project includes theoretical and simulation studies that are framing questions rooted at the black hole boundary that may soon be answered through observations.

By linking together existing telescopes using novel systems, the EHT leverages considerable global investment to create a fundamentally new instrument with angular resolving power that is the highest possible from the surface of the Earth. Over the coming years, the international EHT team will mount observing campaigns of increasing resolving power and sensitivity, aiming to bring black holes into focus.

Why Should We Build the Event Horizon Telescope?
The Event Horizon Telescope -- Avery Broderick



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Published in 12/04/2019

Updated in 19/02/2021

All events in the topic Scientific developments:

29/05/1919Eddington ExpeditionEddington Expedition
10/04/2019 • 10:00:00The first image of a black hole is presented to the publicThe first image of a black hole is presented to the public
05/04/2017The telescope first aims at M87 galaxy center
28/04/2017Katie Bouman's TED Talk
04/11/191525/11/1915Einstein submits his papers on the General Theory of RelativityEinstein submits his papers on the General Theory of Relativity
01/01/1781Discovery of the M87 galaxyDiscovery of the M87 galaxy
01/01/196501/01/1967First developments of very long baseline interferometry (VLBI)
01/01/2009Creation of the Event Horizon Telescope (EHT)
27/11/1783John Michell first imagined "black holes"John Michell first imagined "black holes"
22/12/1915Karl Schwarzschild solves Einstein's equationsKarl Schwarzschild solves Einstein's equations
01/01/1995Existence of black holes is confirmed
11/03/1968Shapiro time delayShapiro time delay
01/01/1978First successful mm-VLBI observations
01/01/19941.3 mm VLBI observations between IRAM telescopes
11/01/1995 • 18:35:00Tremendous Mass Concentration in Strange Galaxy Revealed by VLBATremendous Mass Concentration in Strange Galaxy Revealed by VLBA
01/01/2003VLBI observations at 147 GHz
04/05/2011Gravity Probe B confirms frame dragging
11/02/2016LIGO first detects gravitational wavesLIGO first detects gravitational waves
12/04/2019Katie Bouman's talk at Caltech