5 ms·
The angular resolution is mind-blowing. Combining these telescopes gives us resolutions on the order of the orbit of Mercury around the sun, at a range of our d
by stephengillie 8y ago
The angular resolution is mind-blowing. Combining these telescopes gives us resolutions on the order of the orbit of Mercury around the sun, at a range of our distance from the center of the galaxy. If the Earth were the size of our eyes, it would be like seeing objects of diameter 11.5 meters (37.7 feet) from about 7622 km (4736 mi) away. Almost like seeing a small apartment building in London from Los Angeles, with the naked eye.
> The increased angular resolution provided by the APEX telescope now reveals details in the asymmetric and not point-like source structure, which are as small as 36 million km. This corresponds to dimensions that are only 3 times larger than the hypothetical size of the black hole (3 Schwarzschild radii).
> “It reveals details in the central radio source which are smaller than the expected size of the accretion disk”, adds Thomas Krichbaum, initiator of the mm-VLBI observations with APEX.
Synthesizing with Wikipedia:
> The current highest-resolution measurement, made at a wavelength of 1.3 mm, indicated an angular diameter for the source of 37 μas.[12] At a distance of 26,000 light-years, this yields a diameter of 44 million kilometers. For comparison, Earth is 150 million kilometers from the Sun, and Mercury is 46 million kilometers from the Sun at perihelion. The proper motion of Sgr A* is approximately −2.70 mas per year for the right ascension and −5.6 mas per year for the declination.[13][0]
[0] https://en.wikipedia.org/wiki/Sagittarius_A* https://en.wikipedia.org/wiki/Sagittarius_A*
Diameter
Earth 12,756,000 m
Eye 0.025 m
Ratio 510240000x
- mozumder 8y agoThe best part is that they have to know the alignment the telescopes within .5 mm of each other, across thousands of miles.
- mikeash 8y agoAstounding. How can they do that?
- NeutronStar 8y agoMaths and computers.
- toomuchtodo 8y agoMore precisely, motors and precision position encoders.
- stephengillie 8y agoDistances between locations: Atacama, Argentina - Mauna Kea, HI - 6544 mi - 10532 km Atacama, Argentina - Bishop, CA - 5305 mi - 8358 km Atacama, Argentina - Mt. Graham, Az - 4742 mi - 7632 km Mauna Kea, HI - Mt. Graham, Az - 2936 mi - 4725 km Mauna Kea, HI - Bishop, CA - 2531 mi - 4073 km Mt. Graham, Az - Bishop, CA - 581 mi - 935 km
- jacobush 8y agoImagine if we put some radio telescopes on Mars and ran a baseline between Mars & Earth.
- stephengillie 8y agoWe'd get the largest baseline when the Sun is between the planets. This of course blocks interplanetary communication. Another commenter mentions the 0.5 mm precision needed[0] - how would we overcome the communications issue to get an accurate measurement? [0]https://news.ycombinator.com/item?id=17171476 https://news.ycombinator.com/item?id=17171476
- NeutronStar 8y agoHow long of a time would the Sun be blocking the Earth from Mars?
- lainga 8y agoI imagine the same way the article's array does: with an (interplanetary) version of sneakernet [0], taking independent measurements which are then delivered to be correlated in one place. I think you could keep atomic clocks on Mars and Earth in sync with extremely accurate calculation of the Earth-Mars distance at any time, and thus the propagation delay between them. EDIT: only one star!! [0] https://en.wikipedia.org/wiki/Event_Horizon_Telescope#/media/File:EHT-infography.jpg https://en.wikipedia.org/wiki/Event_Horizon_Telescope#/media...