Posts

Particle Physics

Image
Particle physics (also high energy physics ) is a branch of physics that studies the nature of the particles that constitute matter and radiation . Although the word particle can refer to various types of very small objects (e.g. protons , gas particles, or even household dust), particle physics usually investigates the irreducibly smallest detectable particles and the fundamental interactions necessary to explain their behaviour. By our current understanding, these elementary particles are excitations of the quantum fields that also govern their interactions. The currently dominant theory explaining these fundamental particles and fields, along with their dynamics, is called the Standard Model . Thus, modern particle physics generally investigates the Standard Model and its various possible extensions, e.g. to the newest "known" particle, the Higgs boson , or even to the oldest known force field, gravity . [1] [2]   https://en.wikipedia.org/wiki/Particle_p

SN1987A

Image
SN 1987A was a peculiar type II supernova in the Large Magellanic Cloud , a dwarf galaxy satellite of the Milky Way . It occurred approximately 51.4 kiloparsecs (168,000 light-years ) from Earth and was the closest observed supernova since Kepler's Supernova , visible from earth in 1604. 1987A's light reached Earth on February 23, 1987, [5] and as the first supernova discovered that year, was labeled "1987A". Its brightness peaked in May, with an apparent magnitude of about 3. It was the first opportunity for modern astronomers to study the development of a supernova in great detail, and its observations have provided much insight into core-collapse supernovae . SN 1987A provided the first chance to confirm by direct observation the radioactive source of the energy for visible light emissions, by detecting predicted gamma-ray line radiation from two of its abundant radioactive nuclei. This proved the radioactive nature of the long-duration post-explosio

Gravitational Lensing

Image
A gravitational lens is a distribution of matter (such as a cluster of galaxies ) between a distant light source and an observer, that is capable of bending the light from the source as the light travels towards the observer. This effect is known as gravitational lensing, and the amount of bending is one of the predictions of Albert Einstein 's general theory of relativity . [1] [2] (Classical physics also predicts the bending of light, but only half that predicted by general relativity. [3] ) Although Einstein made unpublished calculations on the subject in 1912, [4] Orest Khvolson (1924) [5] and Frantisek Link (1936) [ citation needed ] are generally credited with being the first to discuss the effect in print. However, this effect is more commonly associated with Einstein , who published a more famous article on the subject in 1936. [6]   https://en.wikipedia.org/wiki/Gravitational_lens   http://w.astro.berkeley.edu/~jcohn/lens.html   Google    

Supernova

Image
A supernova ( / ˌ s uː p ər n oʊ v ə / plural: supernovae / ˌ s uː p ər n oʊ v iː / or supernovas, abbreviations: SN and SNe) is an event that occurs upon the death of certain types of stars. Supernovae are more energetic than novae . In Latin , nova means "new", referring astronomically to what appears to be a temporary new bright star. Adding the prefix "super-" distinguishes supernovae from ordinary novae, which are far less luminous. The word supernova was coined by Walter Baade and Fritz Zwicky in 1931. [1]   Only three, Milky Way naked-eye supernova events have been observed during the last thousand years, though many have been seen in other galaxies using telescopes . The most recent directly observed supernova in the Milky Way was Kepler's Supernova in 1604, but two more recent supernova remnants have also been found. Statistical observations of supernovae in other galaxies suggest they occur on average about three times every century

Vera Rubin

Image
Vera Florence Cooper Rubin ( / ˈ r uː b ɪ n / ; July 23, 1928 – December 25, 2016) was an American astronomer who pioneered work on galaxy rotation rates. [1] She uncovered the discrepancy between the predicted angular motion of galaxies and the observed motion, by studying galactic rotation curves . This phenomenon became known as the galaxy rotation problem , and was evidence of the existence of dark matter . [2] Although initially met with skepticism, Rubin's results were confirmed over subsequent decades. Her legacy was described by The New York Times as "ushering in a Copernican -scale change" in cosmological theory . [1] [3]   https://en.wikipedia.org/wiki/Vera_Rubin

Hubble Deep Fields

Image
 One of the main scientific justifications for building Hubble was to measure the size and age of the Universe and test theories about its origin. Images of faint galaxies give 'fossil' clues as to how the Universe looked in the remote past and how it may have evolved with time. The Deep Fields gave astronomers the first really clear look back to the time when galaxies were forming. The first deep fields – Hubble Deep Field North and South – gave astronomers a peephole to the ancient Universe for the first time, and caused a real revolution in modern astronomy. Subsequent deep imagery from Hubble, including the Hubble Ultra Deep Field , has revealed the most distant galaxies ever observed . Because of the time it has taken their light to reach us, we see some of these galaxies as they were just half a billion years after the Big Bang. http://www.spacetelescope.org/science/deep_fields/   Video  

L2 the Second Lagrangian

Image
L2 is one million miles from the Earth and 94 million miles from the Sun and is a resting place for smaller bodies (such as space telescopes) due to gravitational give and take . In celestial mechanics , the Lagrangian points ( / l ə ˈ ɡ r ɑː n dʒ i ən / ; also Lagrange points , L-points , or libration points ) are positions in an orbital configuration of two large bodies, wherein a small object, affected only by the gravitational forces from the two larger objects, will maintain its position relative to them. Click 4 Videos Click 4 Videos https://en.wikipedia.org/wiki/Lagrangian_point