The Black Hole Sagittarius A*

Posted on by onespaceman2000
Image (Credit): The first image of Sagittarius A*, the supermassive black hole at the center of our galaxy. (EHT Collaboration)

The Event Horizon Telescope (EHT), an array linking together eight existing radio observatories across the planet, has created the first image of the supermassive black hole at the center of the Milky Way galaxy. Named Sagittarius A* after a radio signal coming from a location in the direction of the constellation of Sagittarius (the A and * came later), the black hole is 27,000 light-years away and estimated to be four million times more massive than our Sun. The presence of the black hole was not in question, but capturing an image such as this took many years of work.

A press release from the European Southern Observatory (ESO) quoted EHT Project Scientist Geoffrey Bower from the Institute of Astronomy and Astrophysics, Academia Sinica, Taipei:

We were stunned by how well the size of the ring agreed with predictions from Einstein’s Theory of General Relativity…These unprecedented observations have greatly improved our understanding of what happens at the very centre of our galaxy, and offer new insights on how these giant black holes interact with their surroundings.

For more on the recent breakthrough, you may want to view the ESO Press Conference on the new Milky Way results from the EHT team (here on Youtube), which is followed by a public question and answer event.

Most Distant Galaxy on Record

Posted on by onespaceman2000
Image (Credit): This timeline illustrates the earliest galaxy candidates as well as the history of the universe.(Harikane et al., NASA, EST and P. Oesch/Yale)

Just recently I posted about the discovery of the farthest star. Well, now astronomers have spotted the farthest galaxy. The Harvard Gazette reports that a galaxy named HD1 appears to be about 13.5 billion light-years away and may contain the universe’s first stars or even the earliest black hole discovered to date. The contents of this galaxy is still being studied (and theorized).

The story quotes Fabio Pacucci, an astronomer at the Center for Astrophysics who was involved in the discovery, who stated:

Answering questions about the nature of a source so far away can be challenging… It’s like guessing the nationality of a ship from the flag it flies, while being faraway ashore, with the vessel in the middle of a gale and dense fog. One can maybe see some colors and shapes of the flag, but not in their entirety. It’s ultimately a long game of analysis and exclusion of implausible scenarios.

More review of the data as well as updated data from the James Webb Space Telescope at some point in the future should help to answer questions related to this galaxy.

You can read more about this discover in the Astrophysical Journal. You may also be interested in the accompanying paper published in the Monthly Notices of the Royal Astronomical Society Letters,

Podcast: Joe Rogan and Brian Cox

Posted on by onespaceman2000
Source/Credit: The Joe Rogan Experience on YouTube.

While Joe Rogan has been in some hot water recently, I think we can agree that many of his broadcasts were less controversial and simply fun. He is a good host with plenty of though-provoking questions. I do not want to get into politics, but rather focus on science. And in that case, his two-and-a-half hour discussion on January 28, 2019 with Professor Brian Cox, English physicist and Professor of Particle Physics in the School of Physics and Astronomy at the University of Manchester in the UK, was a terrific way to go over both astronomy and physics.

Some of the topics covered during their talk included the size and complexity of the universe, black holes, wormholes, time travel, the Fermi Paradox, unknown objects at the edge of our solar system, space travel, lasers in space, and the role of artificial intelligence in society. The forum provided plenty of time to cover a large range of topics. It is well worth dropping in and listening.

Some other discussions worth watching include Joe Rogan’s August 22, 2018 discussion with Neil deGrasse Tyson and his May 7, 2020 discussion with Elon Musk.

Top 10 Astronomy Stories from 2021

Posted on by onespaceman2000
Source: Sciencealert.com webpage – “We’re Going Back to Venus! NASA Announces Two New Missions by 2030.”

Before we get too far into 2022, it is worth considering some of the top astronomy stories from 2021. Space.com put together a nice list that I highlighted below.

  1. Discovery of Comet Bernardinelli-Bernstein: “…It may be 10 times wider and 1,000 times more massive than a typical comet.”
  2. Amateur astronomer discovers a new moon around Jupiter: “The new moon, called EJc0061, belongs to the Carme group of Jovian moons.”
  3. NASA will return to Venus this decade: “…NASA has not launched a dedicated mission to the planet since 1989.”
  4. The sun is reawakening: “In early November, for instance, a series of solar outbursts triggered a large geomagnetic storm on our planet.”
  5. James Webb Space Telescope flies into space: “…JWST is heading to an observational perch located about a million miles from our planet.”
  6. Event Horizon Telescope takes high-resolution image of black hole jet: “The end result is a resolution that is 16 times sharper and an image that is 10 times more accurate than what was possible before.”
  7. Scientists spot the closest-known black hole to Earth: “Just 1,500 light-years from Earth…”
  8. Earth’s second ‘moon’ flies off into space: “…the object, known as 2020 SO, is a leftover fragment of a 1960s rocket booster from the American Surveyor moon missions.”
  9. Parker Solar Probe travels through the sun’s atmosphere: “The probe managed to get as low as 15 solar radii, or 8.1 million miles (13 million km) from the sun’s surface.”
  10. Perseverance begins studying rocks on Mars: “Perseverance is taking its observations from the 28-mile-wide (45 kilometers) Jezero Crater, which was home to a river delta and a deep lake billions of years ago.”

Visit the Space.com website for more details on each of these astronomy science stories.