ESO: Detailed observations of material orbiting giant black hole at Milky Way center

The latest report from the European Southern Observatory (ESO):

Most Detailed Observations of Material Orbiting close to a Black Hole
ESO’s GRAVITY instrument confirms black hole status of the Milky Way centre

ESO’s exquisitely sensitive GRAVITY instrument has added further evidence to the long-standing assumption that a supermassive black hole lurks in the centre of the Milky Way. New observations show clumps of gas swirling around at about 30% of the speed of light on a circular orbit just outside a four million solar mass black hole — the first time material has been observed orbiting close to the point of no return, and the most detailed observations yet of material orbiting this close to a black hole. This visualisation uses data from simulations of orbital motions of gas swirling around at about 30% of the speed of light on a circular orbit around the black hole. [Higher-res images]
ESO’s exquisitely sensitive GRAVITY instrument has added further evidence to the long-standing assumption that a supermassive black hole lurks in the centre of the Milky Way. New observations show clumps of gas swirling around at about 30% of the speed of light on a circular orbit just outside its event horizon — the first time material has been observed orbiting close to the point of no return, and the most detailed observations yet of material orbiting this close to a black hole.

ESO’s GRAVITY instrument on the Very Large Telescope (VLT) Interferometer has been used by scientists from a consortium of European institutions, including ESO [1], to observe flares of infrared radiation coming from the accretion disc around Sagittarius A*, the massive object at the heart of the Milky Way. The observed flares provide long-awaited confirmation that the object in the centre of our galaxy is, as has long been assumed, a supermassive black hole. The flares originate from material orbiting very close to the black hole’s event horizon — making these the most detailed observations yet of material orbiting this close to a black hole.

This visible light wide-field view shows the rich star clouds in the constellation of Sagittarius (the Archer) in the direction of the centre of our Milky Way galaxy. The entire image is filled with vast numbers of stars — but far more remain hidden behind clouds of dust and are only revealed in infrared images. This view was created from photographs in red and blue light and forming part of the Digitized Sky Survey 2. The field of view is approximately 3.5 degrees x 3.6 degrees. [ Higher-res images].
While some matter in the accretion disc — the belt of gas orbiting Sagittarius A* at relativistic speeds [2] — can orbit the black hole safely, anything that gets too close is doomed to be pulled beyond the event horizon. The closest point to a black hole that material can orbit without being irresistibly drawn inwards by the immense mass is known as the innermost stable orbit, and it is from here that the observed flares originate.

It’s mind-boggling to actually witness material orbiting a massive black hole at 30% of the speed of light,” marvelled Oliver Pfuhl, a scientist at the MPE. “GRAVITY’s tremendous sensitivity has allowed us to observe the accretion processes in real time in unprecedented detail.

These measurements were only possible thanks to international collaboration and state-of-the-art instrumentation [3]. The GRAVITY instrument which made this work possible combines the light from four telescopes of ESO’s VLT to create a virtual super-telescope 130 metres in diameter, and has already been used to probe the nature of Sagittarius A*.

Earlier this year, GRAVITY and SINFONI, another instrument on the VLT, allowed the same team to accurately measure the close fly-by of the star S2 as it passed through the extreme gravitational field near Sagittarius A*, and for the first time revealed the effects predicted by Einstein’s general relativity in such an extreme environment. During S2’s close fly-by, strong infrared emission was also observed.

We were closely monitoring S2, and of course we always keep an eye on Sagittarius A*,”  explained Pfuhl. “During our observations, we were lucky enough to notice three bright flares from around the black hole — it was a lucky coincidence!

This emission, from highly energetic electrons very close to the black hole, was visible as three prominent bright flares, and exactly matches theoretical predictions for hot spots orbiting close to a black hole of four million solar masses [4]. The flares are thought to originate from magnetic interactions in the very hot gas orbiting very close to Sagittarius A*.

The central parts of our Galaxy, the Milky Way, as observed in the near-infrared with the NACO instrument on ESO’s Very Large Telescope. By following the motions of the most central stars over more than 16 years, astronomers were able to determine the mass of the supermassive black hole that lurks there. [Higher-res images]
Reinhard Genzel, of the Max Planck Institute for Extraterrestrial Physics (MPE) in Garching, Germany, who led the study, explained:

This always was one of our dream projects but we did not dare to hope that it would become possible so soon.” Referring to the long-standing assumption that Sagittarius A* is a supermassive black hole, Genzel concluded that “the result is a resounding confirmation of the massive black hole paradigm.

Notes

[1] This research was undertaken by scientists from the Max Planck Institute for Extraterrestrial Physics (MPE), the Observatoire de Paris, the Université Grenoble Alpes, CNRS, the Max Planck Institute for Astronomy, the University of Cologne, the Portuguese CENTRA – Centro de Astrofisica e Gravitação and ESO.

[2] Relativistic speeds are those which are so great that the effects of Einstein’s Theory of Relativity become significant. In the case of the accretion disc around Sagittarius A*, the gas is moving at roughly 30% of the speed of light.

[3] GRAVITY was developed by a collaboration consisting of the Max Planck Institute for Extraterrestrial Physics (Germany), LESIA of Paris Observatory–PSL/CNRS/Sorbonne Université/Univ. Paris Diderot and IPAG of Université Grenoble Alpes/CNRS (France), the Max Planck Institute for Astronomy (Germany), the University of Cologne (Germany), the CENTRA–Centro de Astrofísica e Gravitação (Portugal) and ESO.

[4] The solar mass is a unit used in astronomy. It is equal to the mass of our closest star, the Sun, and has a value of 1.989 × 1030 kg. This means that Sgr A* has a mass 1.3 trillion times greater than the Earth.

Links

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Einstein’s Monsters: The Life and Times of Black Holes

 

Space policy roundup – Oct.30.2018

A sampling of links to recent space policy, politics, and government related space news and resource items that I found of interest:

Webcasts:

** Episode T+98: Gateway Logistics Services – Main Engine Cut Off – “NASA released a request for information this week about cargo services to the Gateway—big news for the future of NASA and the Gateway. I break down the technical and non-technical bits of that announcement, as well as some updates on Space Force and the Soyuz situation.”

** The Space Show – Sun, 10/28/2018 | Open Lines – David Livingston and his listeners discussed the “SLS, OGLF Advisory Board, SpaceX, electric cars, rocket reusability, U.S. Space Force, Trucks & diesel users, ROI for commercial projects, public benefit for government projects, BFR, SLS Block 2, US Congress, NASA funding, SLS funding, First Man the movie, Neil Armstrong, JWST, public private partnerships”.

** The Space Show – Mon, 10/29/2018Dr. Kirsten Siebach from Rice University discussed “her work regarding Mars, the Mars Rovers, and much more”.

** October 26, 2018 Zimmerman/Batchelor podcast | Behind The Black

Science fiction comic mysteries by Jackie Kingon

If you are looking for some fun space reads during the holiday season, check out Jackie Kingon’s “science fiction comic mysteries”. She sent me the following excerpts of reviews for Chocolate Chocolate Moons:

“Kingon’s prose is often as snappy as her settings…delightful”
—Kirkus Review

“This book is provoking allegory with satirical elements that mock the weight loss industry and society’s view of eating as a whole.”
—Online Book Club

“A humorous romp, sure to please many a reader.”
—Midwest Book Review

And for Sherlock Mars:

Molly’s Bistro, owned by Earthling Molly Marbles, is doing well in Mars’ capital of New Chicago. Virtual Vittles, a virtual-reality restaurant, has opened nearby, but when its dining experience leaves customers hungry, they make a beeline for Molly’s place. She and Virtual Vittles owner Rick Frances eventually collaborate on a dining event; unfortunately, it ends with Rick found dead at Molly’s Bistro. Molly, who previously helped detectives solve a different mystery, works the murder case…An undeniably fun tale with a protagonist who can apparently handle anything…

—Kirkus Review

The Space Show this week – Oct.29.2018

The guests and topics of discussion on The Space Show this week:

1. Monday, Oct. 29, 2018; 2-3:30 pm PDT (4-5:30 pm CDT, 5-6:30 pm EDT): We welcome Dr. Kirsten Siebach from Rice University to discuss her Mars work.

2. Tuesday, Oct.30, 2018: 7-8:30 pm PDT; 9-10:30 pm CDT; 10-11:30 pm EDT: We welcome Dean Cheng on the idea of a U.S. Space Force.

3. Wednesday, Oct. 31, 2018: Hotel Mars. See Upcoming Show Menu and the website newsletter for details. Hotel Mars is pre-recorded by John Batchelor. It is archived on The Space Show site after John posts it on his website.

4. Friday, Nov. 2, 2018; 9:30 AM-11 pm PDT, (12:30 -2 pm EDT; 11:30 am -1 pm CDT. We welcome back Dr. Marc Rayman on the closing of the Dawn Mission and Ceres updates.

5. The Sunday, Nov. 4, 2018 program from 12-1:30 pm PDT, (3-4:30 pm EDT, 2-3:30 pm CDT): We welcome space artist Doug Forrest. See his Apollo Arts gallery.

See also:
* The Space Show on Vimeo – webinar videos
* The Space Show’s Blog – summaries of interviews.
* The Space Show Classroom Blog – tutorial programs

The Space Show is a project of the One Giant Leap Foundation.

Sampling of recent programs:

  • Tue, 10/23/2018 – 19:00William Ketchum talked about his “book, “To The Moon On A Slide Rule,” early ICBM and rocket history, early space program, Surveyor missions, lunar surface, nuclear propulsion, NASA, SLS, Gateway and much more”.
The Space Show - David Livingston
David Livingston

Video: TMRO Orbit 11.42 – “Hubble’s fate, Mars Cubes and space brains”

The latest episode of TMRO.tv Space is now available: Hubble’s fate, Mars Cubes and space brains – Orbit 11.42 – TMRO

This is the episode of the season where we have the ultimate answer to the life universe and everything! I had also been eager to try a new news format that was more round-table and conversational. Since there was no standard guest this week we made it happen! Let me know what you think in the comments. A bit long, but overall I liked it!

Launch and space news topics covered:

Launch Minute:

  • Soyuz 2.1B | Lotos-S1 | Kosmos-2528
  • Long March 4B | Haiyang 2B

Space News:

  • NASA is preparing for Hubble’s return
  • This is your brain on space
  • NASA seeking Lunar Gateway Cargo Delivery
  • Hayabusa-2 prepares for Ryugu touchdown
  • Major first step for Pluto Orbiter Mission
  • First Image of Mars taken by a CubeSat
  • Virgin’s LauncherOne and SpaceShipTwo edging closer to space

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Chasing New Horizons: Inside the Epic First Mission to Pluto