-
----------------------------- 1918 - Blackholes and Galaxies?
-
-
- The first super-massive Blackholes were discovered in 1963. The first discovery had a red-shift that indicated it was receding at 16% the speed of light. It became known as a “Quasar” and soon hundreds more were discovered.
-
- These Quasars can shine brighter then their entire host galaxy, or, other whole galaxies. The rapid variations in brightness implied that the actual light radiation was coming from something smaller than our Solar System. These small centers of galaxies were spewing jets of ionized gas millions of lightyears into space from their rotational poles. The jets were plasma that smashed into gas surrounding the galaxy heating the gas to many millions of degrees Kelvin. The hot gas emitted X-rays.
-
- The gas was falling into the Blackhole circling to velocities nearly the speed of light. The friction within the gas creates the heat that emit’s the X-ray radiation.
-
- In 2002 astronomers observing the motion of individual stars surrounding the Blackhole at the center of our Milky Way Galaxy proved that the center was a mass of 4.3 million Solar Mass. The area emitting this radiation was so small it had to be the concentrated energy of a Blackhole.
-
- In 2005 the same type analysis confirmed the size of the Blackhole at the center of the Andromeda Galaxy.
-
- Blackholes appear to control the evolution of all the large galaxies. But how? We need to explain why the mass of a central Blackhole does not correlate with the mass of the galaxy disk. For similar size galaxies, one can have a Blackhole of 1,500 Solar Mass. Another can have a Blackhole of 1,000,000,000 Solar Mass. Something else is going on?
-
- When the Universe was 2 to 6 billion years old, during the era of rapid Quasar development, many smaller Blackholes merged into larger Blackholes.
-
- A Blackhole is a pit in the fabric of space-time. Space and Time are interchangeable. You can not have one without the other.
-
- Blackholes are places in space where the density of matter grows so high that all matter is crushed into a single point, a Singularity. The Singularity is the center. The rim of the Blackhole is the Event Horizon. The Event Horizon is the edge where even light photons, get turned around by the pull of gravity and sent back into the Singularity.
-
- There are two types of Blackholes. Stellar Blackholes that form from a single massive star. And, Galactic Blackholes that are the centers of most galaxies and have a mass of million, or billions, Solar Mass.
-
- Spinning Blackholes have an additional kinetic energy in addition to the gravitational energy. Spinning Blackholes can power jets of gas and dust exiting out of their rotational poles.
-
- The rotational velocity of a spinning Blackhole can be calculated :
-
------------------- Rotational Velocity = v = a * c / ( 1 + ( 1 - a^2) ^ ½ )
-
--------------------- c = the speed of light = 186,000 miles per second
-
--------------------- a = the angular momentum
-
- If the spin is 31.3% of its maximum. Then:
-
---------------------- v = 0.16 *c = 16% the speed of light.
-
- There are 3 ways astronomers can measure the mass of a Blackhole. If stars can be seen orbiting the Blackhole the speed and radius distance can be used to calculate the mass.
-
- If the light from the Accretion Disk flickers the duration of the flicker corresponds to how long light took to travel from one side to the other side of the disk. Light speed and duration time can be used to calculate distance across the disk. The size of the Accretion Disk can be used to correlate with other Blackholes to estimate the mass.
-
- If the above data can not be collected, astronomers can us the brightness alone of the Accretion Disk to estimate the mass of the Blackhole.
-
- We need a lot of estimating to measure something we can not see.
-
- Blackhole folklore gives the impression that Blackholes are enormous beasts devouring everything in their cosmic neighborhood.
-
- Astronomers can get very sure of the thing that they think they are very sure of. Actually Blackholes are surprisingly tiny spheres of influence. Their gravitational reach is surprisingly small, only a few lightyears. Stars can whisk by within a few thousandths of a lightyear and survive unscathed.
-
- If a galaxy were the size of the Earth the central Blackhole would be the size of a penny.
-
- Defining the correlation between the size of the Central Blackhole and the size of the galaxy as proven to be difficult. There appear to be many different factors involved.
-
- Blackhole evolution could have a feedback system , a cosmic thermostat, that shuts off development. Rotating hot gas creates jets shooting out the poles and inflating bubbles that create eddies and turbulence that could cut off further star formation in the galaxy.
-
- Cold gas makes stars and feeds Blackholes. 10 to 12 billion years ago galaxies were 50% gas. Today, large galaxies are only 5 to 15% gas.
-
- At lower masses the galaxy population is dominated by spiral galaxies.
-
- A galaxy can evolve as a ball ( elliptical ) or a disk depending on where it is born and how the cosmic web is feeding it.
-
- The study is still open ended trying to explain the correlation between the size of Blackholes and the size of their host galaxies. Stay tuned, an announcement will be made shortly. Or, maybe astronomy will just give us more mysteries to solve.
-
------------------------------------------------------------------
-
- See Reviews #1908 - How the mass of the Blackhole is calculated
-
- #1891 - The Blackhole is inescapable for stars greater than 20 Solar Mass.
-
- # 1882 - Could Blackholes explain Dark Matter?
-
- #1869 - How big can Blackholes get?
-
- #1843 - Great Walls in space with Blackholes.
-
- # 1819 - The history of discovery of Blackholes. This review also lists 21 other Reviews on the subject of Blackholes. All the way back to #592 dated December, 2005.
-
- --------------------------------------------------------------------------------------
---- Comments appreciated and Pass it on to whomever is interested. ----
--- Some reviews are at: -------------- http://jdetrick.blogspot.com -----
-- email feedback, corrections, request for copies or Index of all reviews
- to: ------- jamesdetrick@comcast.net ------ “Jim Detrick” -----------
- https://plus.google.com/u/0/ -- www.facebook.com -- www.twitter.com
----- 707-536-3272 ---------------- Saturday, January 14, 2017 -----
------------------------------------------------------------------------------------------
No comments:
Post a Comment