-
-
------------------- 2183 - The Biggest Thing in the Universe
-
- What is the biggest thing we have ever found in the Universe? Think about it. What could it be, a star? No. A galaxy then? No. A cluster of galaxies? No. The answer is, “ a Lyman-alpha Blob”.
-
- A Lyman-alpha Blob is a 3-dimensional filament of galaxies that is 200,000,000 light years across. This filament was formed 2,000,000 years after the Big Bang. It is the largest known structure yet discovered in the Universe. The structure has 33 blobs of concentrations of gas and dust with each blob is 10 times bigger than our Milky Way Galaxy.
-
- Astronomers expect the Universe to look relatively “smooth” 2,000,000 years after the Big Bang. This filament of blobs is not so smooth. Inside the blobs are concentrations of galaxies that are 4 time denser than the Universe’s average. Two of the blobs studied were 400,000 lightyears across, about the twice the size of the Andromeda Galaxy that has a radius of 110,000 lightyears.
-
- This gas structure of galactic filaments is called a Lyman-alpha blob because we see them through Lyman-alpha emission lines of hydrogen.(Note:1) The blobs are regions where gas is collapsing under its own gravity to form a galaxy.
-
- The glow of the gas, or the radiation we see, is caused by the death of many massive stars born early in the history of the Universe, living out very short lives, then exploding as giant supernova. The explosions cause “shock heating“, or a “galactic solar wind“, that heats up the interstellar gas and causes Lyman-alpha emissions.
-
- Gas inside the blobs is moving at speeds greater than 1,080,000 miles per hour, 300 miles per second. Using the speed of the orbiting gas to calculate the mass of the gas concentrations astronomers calculate the blobs to be 10 times more massive than the Milky Way Galaxy.
-
- The 33 blobs come in all variety of shapes and brightness. Some have bubble-like features caused by the galactic winds forming a giant shell.
-
- One interstellar gas cloud recently discovered has an hourglass figure. This shape had been predicted by astronomers because it is what would result if a collapsing gravitational field and a collapsing magnetic field interacted, in theory.
-
- This gas cloud contains two proto-stars 980 lightyears from Earth in the constellation Perseus. The interstellar molecular cloud has the mass of 130,000 Suns. The gravitationally collapsing molecular cloud has to overcome the support provided by the magnetic field. The combination of gravity pulling in and the magnetic pressure pushing out creates the hourglass pattern.
-
- The magnetic field aligns the dust grams in the molecular cloud allowing astronomers to measure the field’s geometry and its strength through detection of the polarization of the dust emissions. The hourglass figure becomes a real life example of a theoretically predicted magnetic structure. Approximately a million years in the future two sun-like stars will shine where this hourglass cloud exists today.
-
- Footnotes:
-
(1) Lyman-alpha radiation is emitted by hydrogen at 121.6 nanometers wavelength. The Lyman series is a series of spectral lines for hydrogen. It is in the Ultraviolet wavelengths. The 4 energy levels are 10.19 eV, 12.1 eV, 12.8 eV, 13.6 electron volts.
-
(2) Electrons are known to have both wave and particle properties and they occupy only certain allowed energy levels in the atom. An electron can absorb energy, a photon, and jump from its ground state, level 1, to a higher energy state, level 2, or alpha level. This can happen only if the electron absorbs a photon of wavelength 121.6 nanometers, which is equivalent to 10.19 electron volts of energy. The reverse process occurs when the electron falls from alpha level to ground level in the hydrogen atom.
-
(3) This model of the atom was suggested by Niels Bohr in 1913. If a quantum of light is radiated by the electron a sizeable fraction of its kinetic energy is lost all at once, and, the electron takes on a new orbit closer to the nucleus.
-
- The angular momentum of the electron drops by Planck’s constant / 2 *pi.
-
- Angular momentum = (1.0545*10^-27 erg-seconds) * (the number of the orbit, 1,2,3,or,4) / 2*pi .
-
- November 21, 2018 675
---------------------------------------------------------------------------------------
---- 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
-------------------------- Saturday, November 24, 2018 --------------------------
------------------------------------------------------------------------------------------
No comments:
Post a Comment