This Week’s Show Notes
Show 94. Notes for April 9th
Shows are recorded live on the Darkmatterradio.net every Wednesday at 8:00 PM Eastern Standard Time, GMT/00:00 UTC and podcasts of the live shows posted the following Thursday. You can join the Chat Room on right sidebar of our home page and interact live each week.
We are without a newscaster, and still have Andy Fleming with astronomy clips, see below.
Former President Bill Clinton Talks of Aliens on Kimmel
Jimmy Kimmel tells Bill Clinton that, if he were elected president, the first thing he would do is find out about UFOs. Clinton speaks of his experience in looking into the matter while serving as President, and says he would not be surprised if we are visited. Check out the video clip in our shownotes, along with other links and sources of our UFO news.
Sagittarius A star and the Milky Way’s Galactic Centre
by Andy Fleming
This week we’re looking at the latest news about Sagittarius A*, the supermassive black hole at the centre of our galaxy.
In the coming weeks, astronomers may see this monster having a cosmic snack. A gas cloud called G2 is in in the process of colliding with it. G2 has a mass of three Earths and no match for Sagittarius A*, which has the mass of four million suns. If the black hole devours much of the cloud, fireworks could ensue. Heated to billions of degrees as it spirals inward, the doomed gas cloud may emit a last gasp of radiation, from across the electromagnetic spectrum.
Even if the encounter proves a dud, it may still provide an insight about the feeding habits of supermassive big black holes. The first stage could come just weeks after the cloud, already stretched into a spaghetti-like strand by the black hole’s gravity, makes its closest approach to Sagittarius A*. At closest approach, the cloud’s distance from the black hole will still be about 200 times Earth’s distance from the sun. Nonetheless, the passage might be near enough for G2 to plough into the outer edge of the swirling disk of matter believed to surround and feed the black hole.
The shock wave generated by that encounter may create X-rays and radio waves that could be detected by telescopes. If the cloud contains a star at its centre, as some astronomers have proposed, it may produce a stronger shock and generate more light. The encounter could have another effect: Disruptions in the cloud might alter the direction in which radio waves vibrate as they travel through. Simultaneous observations with telescopes tuned to different radio wavelengths have a chance of discerning the waves’ twists, giving astronomers new details about the cloud’s properties.
But most of the potential fireworks are perhaps decades away. Moreover, astronomers think that if the gas cloud is to be swallowed, it will have to lose much of its angular momentum, or orbital rotation, around the black hole.
Next year, the Event Horizon Telescope that has already examined Sagittarius A*, will gain enough resolution to discern the light that just misses being dragged into Sagittarius A* but is bent by the black hole’s gravity into a halo that frames it. Deviations from the predicted shape of the halo would indicate that Einstein’s theory of gravity needs revision.
Guest is Ron Westrum, who is a emeritus professor of Sociology at Eastern Michigan University, holding an honors B.A. from Harvard in Social Relations and a Ph.D from the University of Chicago in Sociology. Dr. Westrum is a specialist on the sociology of science and technology. Ron has developed an interest in UFOs.