Multiverse Theory

The multiverse theory is the hypothetical existence of a set of multiple possible universes, which includes our universe. These multiple universes are composed of everything that physically exists: the entirety of space and time, all forms of matter, energy and momentum, and the physical laws and constants that rule them. These different universes contained within the multiverse are sometimes called parallel universes. The structure of the multiverse, and the nature of each universe held within it, depend on the specific multiverse hypothesis considered.

Multiverses have been hypothesized in physics, astronomy, and philosophy. The word "multiverse" was coined in 1895 by psychologist William James.

Multiverse Theory

IC 2118 Witch Head Nebula

IC 2118 Witch Head Nebula is an ancient supernova remnant or gas cloud which is located in the constellation of Eridanus and is illuminated by nearby supergiant Rigel in Orion. The IC 2118 lies 900 light-years away from Earth, in the Eridanus constellation. Its dust particles reflect blue light better than red; hence the Witch Head blue color. The Witch Head Nebula glows mainly by light reflected from Rigel. The same physical process makes the Earth's daytime sky to appear blue. The IC 2118 lies at 2.6° to the west of Rigel.

Cosmic Inflation

Cosmic inflation is the exponential expansion of the universe at the end of the grand unification epoch, 10-36 seconds after the Big Bang. This exponential expansion was driven by a negative-pressure vacuum energy density. Cosmic inflation theory states that the primeval universe went through a phase of exponential expansion, ballooning almost instantaneously from less than the size of an atom to about golf-ball size. The term "inflation" is also used to refer to the hypothesis that inflation occurred, to the theory of inflation, or to the inflationary epoch. As a direct consequence of this expansion, all of the observable universe originated in a small causally connected region.

Cosmic inflation answers the conundrum of the big bang theory: why does the universe appear flat, homogeneous and isotropic in accordance with the cosmological principle when one would expect, on the basis of the physics of the big bang, a highly curved, heterogeneous universe? Cosmic inflation predicts the existence of gravity waves, as well as fluctuations in the density and temperature of radiation left over from the big bang. Inflation also explains the origin of the large-scale structure of the cosmos. Quantum fluctuations in the microscopic inflationary region, magnified to cosmic size, become the seeds for the growth of structure in the universe.

Cosmic inflation was proposed almost simultaneously by by Alan Guth in the United States and Alexei Starobinski in the Soviet Union.

Rigel

Rigel is a star in the constellation Orion. With visual magnitude 0.18, it is the sixth brightest star in the sky. Rigel is moving through a region of nebulosity and lights up several dust clouds in its vicinity, the most notable being the IC 2118, which is called the Witch Head Nebula.

Rigel is a contrasting blue supergiant. The theory of stellar structure and evolution shows that Rigel has a mass 18 times that of the Sun. With a dead helium core, it is still in a swelling and cooling phase. It is located at 850 light years away from the Solar System. Rigel should eventually expand to become a red supergiant very much like Betelgeuse.

NGC 147

NGC 147 is a Dwarf spheroidal galaxy which is located in the constellation Cassiopeia, 2.58 million light years away from Earth . NGC 147 is a satellite galaxy of Andromeda (M31) and belongs to the Local group of galaxies. It forms a physical pair with the nearby galaxy NGC 185, another remote satellite of M31. It is fainter but slightly larger than NGC 185, but they are both visible in small telescopes.

NGC 147 was discovered by John Herschel in September 1829 and the membership of NGC 147 in the Local Group was confirmed by Walter Baade in 1944 when he was able to resolve the galaxy into individual stars with the 100-inch (2.5 m) telescope at Mount Wilson near Los Angeles.

NGC 147 DDO3

Ursa Major I Dwarf

Ursa Major I Dwarf, or UMa I dSph, is a dwarf spheroidal galaxy which belongs to the Local Group and is satallite of the Milky Way galaxy. It measures only a few thousand light-years in diameter. The Ursa Major Dwarf is the second least luminous galaxy known to the Boötes Dwarf (absolute magnitude -5.7). The absolute magnitude of the galaxy is estimated to be only -6.75, meaning that it is less luminous than some stars in the Milky Way. It has been described as similar to the Sextans Dwarf Galaxy. Both galaxies are ancient and metal-deficient.

Ursa Major Dwarf galaxy lies at 330,000 light-years (100 Kpc) away from the Earth; twice the distance to the Large Magellanic Cloud; the largest and most luminous satellite galaxy of the Milky Way. It was discovered by Beth Willman in 2005.

One must not mistake the other celestial object which is also called Ursa Major Dwarf, discovered by Edwin Hubble in 1949. It was designated as Palomar 4, which, due to its peculiar look, was temporary suspected to be either a dwarf spheroidal or elliptical galaxy. Nevertheless, it has since been found to be a very distant (about 360,000 ly) globular cluster belonging to our galaxy.

Dwarf Spheroidal Galaxy

A dwarf spheroidal galaxy is a low luminosity type of galaxy which is found as a satellite galaxy of the Milky Way and the Andromeda Galaxy M31. It is spheroidal in shape, lower luminosity, and similar to dwarf elliptical galaxies in appearance and properties such as little to no gas or dust. Dwarf spheroidal galaxies belong to the Local Group. Up until 2005, there were nine dwarf spheroidal galaxies in the Local Group, but the Sloan Digital Sky Survey has discovered eleven more. These types of galaxies might be the most common galaxies in the universe.

A dwarf spheroidal galaxy has extremely large amounts of dark matter. In the past, most astronomers believed that a dwarf spheroidal galaxy was merely a large, low density globular cluster. Nevertheless detailed studies in the last 20 years have revealed that the dwarf spheroidal galaxies have a more diverse set of properties and contain more complex stellar populations than the globular cluster analogy would predict.

Ursa Minor Dwarf

The Ursa Minor Dwarf is a dwarf elliptical galaxy which is a small satellite galaxy of the our Milky Way. It was discovered by A.G. Wilson of the Lowell Observatory in 1954. The Ursa Minor Dwarf is part of the Ursa Minor constellation. It is composed of older stars. Apparantly there is little star formation in the Ursa Minor Dwarf galaxy. It is located at 240,000 light years from our Solar System.

The Ursa Minor Dwarf galaxy has a right ascension of 15h 09m 08.5s, and a declination of +67° 13′ 21″.

The Hertzsprung-Russel Diagram

The Hertzsprung–Russell diagram is a scatter graph of stars which shows the relationship between the stars' absolute magnitudes and their spectral types or classifications and effective temperatures. Hertzprung-Russell diagrams are not pictures or maps of the locations of the stars. Rather, they plot each star on a graph measuring the star's absolute magnitude or brightness against its temperature and color. The Hertzsprung–Russell diagram is also referred to by the abbreviation H-R diagram or HRD. They are also known as colour-magnitude diagrams or CMD. The diagram was created circa 1910 by Ejnar Hertzsprung and Henry Norris Russell and represents a major step towards an understanding of stellar evolution or "the lives of stars".

There are several forms of the Hertzsprung–Russell diagram. The original diagram displayed the spectral type of stars on the horizontal axis and the absolute magnitude on the vertical axis. The first quantity is difficult to plot as it is not a numerical quantity and in modern versions of the chart it is replaced by the B-V color index of the stars. This type of diagram is what is often called a Hertzsprung–Russell diagram, or specifically a color-magnitude diagram, and it is often used by observers. In cases where the stars are known to be at identical distances such as with a star cluster, a color-magnitude diagram is often used to describe a plot of the stars in the cluster in which the vertical axis is the apparent magnitude.

Omega Centauri (NGC 5139)

Omega Centauri (NGC 5139) is a globular cluster in the constellation of Centaurus. It is the biggest of globular clusters of the Milky Way galaxy. The stars of this cluster formed over a 12-billion-year period of time, with several starburst peaks.

Omega Centauri is situated about 18,300 light-years away from Earth and contains several million Population II stars. The stars in its center are very crowded and they are believed to be only 0.1 light years away from each other. NGC 5139 has a total mass of five million Suns and its stars are gravitationally bound into a spherical configuration, with the highest density of stars at the center. Omega Centauri was discovered by Edmond Halley in 1677 who listed it as a Nebula.

M96 Group

The M96 Group is the Leo I Group, which is a group of galaxies in the constellation Leo. It contains between 8 and 24 galaxies, and includes three Messier objects. The group is one of many groups that lies within the Virgo Supercluster. Using the Hubble Space Telescope, 8 Delta Cephei variable stars were found in the brightest galaxy of the group, M96, and were able to derive its distance from the Cepheid period-luminosity relation: M96 is 231+/-13 times more remote from us than the Large Magellanic Cloud, thus 12.7+/-0.8 Mpc (41+/-2 million light years).

Carina Dwarf

The Carina Dwarf Spheroidal is a dwarf galaxy which is satellite to the Milky Way from which it is receding at 230 km/s. The Carina Dwarf was discovered in 1977 with the UK Schmidt Telescope. It may have formed several billion years after the formation of the other satellite galaxies of the Milky Way. Its older stars are younger than 7 billion years.

M32

M32 is a dwarf elliptical galaxy of only about 3 billion solar masses, and a linear diameter of some 8,000 light years, which is very small compared to its giant spiral-shaped neighbor the Andromeda galaxy. It is a member of the Local Group. The M32 is located 2.65 million light years away in the constellation Andromeda.

Tidal effects trigger a massive star burst in the core of the M32, which explains its high density. The M32 has an outer disk.

Draco Dwarf

The Draco Dwarf is a spheroidal galaxy which is situated in the direction of the Draco Constellation at 34.6°. It belongs to the Local Group and is a satellite galaxy of the Milky Way galaxy. The Draco Dwarf was discovered by Albert George Wilson of Lowell Observatory in 1954.

It is one of the faintest companions to our Milky Way. The Draco Dwarf galaxy may potentially hold large amounts of dark matter.

Messier M54

Messier M54 (NGC 6715) is a conspicuous globular cluster, which was discovered by Charles Messier on July 24, 1778. It is about 85,000 light years away from the Solar System and is situated in the Sagittarius Dwarf Elliptical Galaxy which belongs to the Local Group of galaxies. The M54 is one of the most luminous known globular clusters with an absolute visual magnitude M_v of -10.01, a brilliance of about 850,000 suns like ours. It is outshined only by the spectacular Omega Centauri in our Milky Way.

Sagittarius Dwarf Elliptical Galaxy

The Sagittarius Dwarf Elliptical Galaxy is an elliptical galaxy that belongs to the Local Group and is satellite of the Milky Way. It is roughly 10,000 light-years in diameter, and is about 70,000 light-years away from Earth. The Sagittarious Dwarf Spheroidal Galaxy travels in a polar orbit at a distance of about 50,000 light-years from the core of the Milky Way. It contains the brightest globular cluster known in the universe, the Messier M54.

NGC 1818

NGC 1818 is a young globular cluster that is estimated to be about 40 million years old. All known globulars, except for the NGC 1818, have their age estimated to be between 4-14 billion years. It is part of the Large Magellanic Cloud. Astronomers have found a young white dwarf star in its center. It has recently formed following the burnout of a red giant. The NGC has mass ~3×104 Msun.

Tarantula Nebula (NGC 2070)

The Tarantula Nebula (NGC 2070) is a giant star forming region (H II region) in the Large Magellanic Cloud. It is more than 1,000 light-years in diameter and 180,000 light years away from the Solar System. The Tarantula Nebula is an extremely luminous non-stellar object.

Within the Tarantula (NGC 2070), intense radiation and stellar winds gush out from the central young cluster of massive stars, cataloged as R136, energizing the nebular glow and shaping the spidery filaments. The Tarantula Nebula NGC 2070 was first cataloged as a star, 30 Doradus, but Nicolas Louis de Lacaille recognized its nebular nature in 1751.

Canis Major

The Canis Major dwarf galaxy is an irregular dwarf galaxy which neighbors the Milky Way and belong to the Local Group. It contains about one billion stars with high percentage of red giant stars. Canis Major dwarf galaxy is located about 25,000 light-years away from our Solar System.

The Canis Major dwarf galaxy main body is degraded and tidal disruption causes a long filament of stars to trail behind it as it orbits the Milky Way. It forms a complex ringlike structure sometimes referred to as the Monoceros Ring which wraps around our galaxy three times.

Eagle Nebula (M16)

The Eagle Nebula (M16) is a young open cluster of stars in the constellation Serpens. It was discovered by Jean-Philippe de Cheseaux in 1745-46. Its shape is reminiscent of an eagle. The Eagle Nebula is the subject of a famous photograph by the Hubble Space Telescope, showing pillars of star-forming gas and dust within the nebula.

The Eagle Nebula lies about 6,500 light years away from the earth.