Biggest Things in Space
The Universe is Immensely Large and so are Some of the Things Found Within It



 
Biggest Things in Space
The Universe is Immensely Large and so are Some of the Things Found Within It

 
We can't compare anything on earth to the biggest things known in space. The Lymann Alpha blob is a bubble like structure containing countless galaxies -- perhaps the biggest object in the entire universe.

Regions of radio-emitting gas called "radio lobes" could be even bigger. Then there are super galaxy clusters which are hundreds of galaxies merged together due to cosmic collisions.

Discover which is the largest planet, star, star cluster, constellation, black hole, volcano, galaxy, explosions, moon, storm, impact crater and "void" in space.


 
The universe is immensely large and possibly infinite in volume. The region visible from Earth (the observable universe) is a sphere with a radius of about 46 billion light years, based on where the expansion of space has taken the most distant objects observed.

For comparison, the diameter of a typical galaxy is only 30,000 light-years, and the typical distance between two neighboring galaxies is only 3 million light-years.

As an example, our Milky Way Galaxy is roughly 100,000 light years in diameter, and our nearest sister galaxy, the Andromeda Galaxy, is located roughly 2.5 million light years away.

There are probably more than 100 billion galaxies in the observable universe. Typical galaxies range from dwarfs with as few as ten million stars up to giants with one trillion stars, all orbiting the galaxy's center of mass.

Thus, a very rough estimate from these numbers would suggest there are around one sextillion stars in the observable universe; though a 2010 study by astronomers resulted in a figure of 300 sextillion (3×1023).


The observable matter is spread homogeneously (uniformly) throughout the universe, when averaged over distances longer than 300 million light-years.

However, on smaller length-scales, matter is observed to form "clumps", i.e., to cluster hierarchically; many atoms are condensed into stars, most stars into galaxies, most galaxies into clusters, superclusters and, finally, the largest-scale structures such as the Great Wall of galaxies.

The observable matter of the universe is also spread isotropically, meaning that no direction of observation seems different from any other; each region of the sky has roughly the same content.

The universe is also bathed in a highly isotropic microwave radiation that corresponds to a thermal equilibrium blackbody spectrum of roughly 2.725-kelvins.

The hypothesis that the large-scale universe is homogeneous and isotropic is known as the cosmological principle, which is supported by astronomical observations.

A study of the amount of dark matter in the universe suggests that the universe itself may continue to expand indefinitely.

Researchers say that the universe will likely then become a cold, dead cosmic wasteland. The study was conducted by an international team of researchers led by Professor Eric Jullo at NASA's Jet Propulsion Laboratory in California.

The researchers used data from the Hubble Space Telescope showing the way that light was distorted, known as a gravitational lens, from a large galactic cluster known as Abell 1689 to estimate the amount of dark energy to be about three quarters of the universe.

Dark energy is a completely invisible force that is constantly acting upon the universe. Its existence is known only because of its effects on the expansion of the universe. As the universe expands and cools, the temperature will approach absolute zero. Jullo says that scientists can now say, for the first time, that the universe "will continue to accelerate and the universe will expand forever".


Dark Matter

In astronomy and cosmology, dark matter is matter that is inferred to exist from gravitational effects on visible matter and gravitational lensing of background radiation, but that neither emits nor scatters light or other electromagnetic radiation (and so cannot be directly detected via optical or radio astronomy).

Its existence was hypothesized to account for discrepancies between calculations of the mass of galaxies, clusters of galaxies and the entire universe made through dynamical and general relativistic means, and calculations based on the mass of the visible "luminous" matter these objects contain: stars and the gas and dust of the interstellar and intergalactic medium.

According to observations of structures larger than solar systems, as well as Big Bang cosmology interpreted under the Friedmann equations and the FLRW metric, dark matter accounts for 23% of the mass-energy density of the observable universe.

In comparison, ordinary matter accounts for only 4.6% of the mass-energy density of the observable universe, with the remainder being attributable to dark energy.
From these figures, dark matter constitutes 83%, (23/(23+4.6)), of the matter in the universe, whereas ordinary matter makes up only 17%. Dark matter was postulated by Fritz Zwicky in 1934 to account for evidence of "missing mass" in the orbital velocities of galaxies in clusters.

Subsequently, other observations have indicated the presence of dark matter in the universe.

These observations include the rotational speeds of galaxies, gravitational lensing of background objects by galaxy clusters such as the Bullet Cluster, and the temperature distribution of hot gas in galaxies and clusters of galaxies.

Dark matter plays a central role in state-of-the-art modeling of structure formation and galaxy evolution, and has measurable effects on the anisotropies observed in the cosmic microwave background.

All these lines of evidence suggest that galaxies, clusters of galaxies, and the universe as a whole contain far more matter than that which interacts with electromagnetic radiation.

The largest part of dark matter, which does not interact with electromagnetic radiation, is not only "dark" but also, by definition, utterly transparent. As important as dark matter is believed to be in the cosmos, direct evidence of its existence and a concrete understanding of its nature have remained elusive.

Though the theory of dark matter remains the most widely accepted theory to explain the anomalies in observed galactic rotation, some alternative theoretical approaches have been developed which broadly fall into the categories of modified gravitational laws, and quantum gravitational laws.



Shapley Supercluster

The Shapley Supercluster or Shapley Concentration (SCl 124) is the largest concentration of galaxies in our nearby Universe that forms a gravitationally interacting unit, thereby pulling itself together instead of expanding with the Universe.

It appears as a striking overdensity in the distribution of galaxies in the constellation of Centaurus, approximately 650 million light years away (z=0.046). In recent times, the Shapley supercluster was rediscovered by Somak Raychaudhury, from a survey of galaxies from UK Schmidt Telescope Sky survey plates, using the Automated Plate Measuring Facility (APM) at the University of Cambridge in England.

In this paper, the Supercluster was named after Harlow Shapley, in recognition of his pioneering survey of galaxies in which this concentration of galaxies was first seen. Around the same time, Roberto Scaramella and co-workers had also noticed a remarkable concentration of clusters in the Abell catalogue of clusters of galaxies: they had named it the Alpha concentration.



Boötes Void

In astronomy, voids are the empty spaces between filaments, the largest-scale structures in the Universe, that contain very few, or no, galaxies.

They were first discovered in 1978 during a pioneering study by Stephen Gregory and Laird A. Thompson at the Kitt Peak National Observatory.

Voids typically have a diameter of 11 to 150 Mpc; particularly large voids, defined by the absence of rich superclusters, are sometimes called supervoids. Voids located in high-density environments are smaller than voids situated in low-density spaces of the universe.

Voids were formed by baryon acoustic oscillations in the Big Bang by collapses of mass followed by implosions of the compressed baryonic matter.

The shells of the voids are the remnants of shock fronts left by this process. The decoupling of matter from radiation when the universe became transparent "froze" the voids and shock fronts in place.

The Boötes void or the Great Void is a huge and approximately spherically shaped region of space, containing very few galaxies. It is located in the vicinity of the constellation Boötes, hence its name. Its centre is located at approximately right ascension 14h 20m and declination 26°.

At nearly 250 million light-years in diameter, or nearly 236,000 Mpc3 in volume, the Boötes void is one of the largest known voids in the universe, and is referred to as a supervoid. Its discovery was reported in Robert Kirshner et al. (1981), as part of a survey of galactic redshifts.Other astronomers soon discovered that the void contained a few galaxies.

In 1987, J. Moody, Robert Kirshner, G. MacAlpine, and S. Gregory published their findings of eight galaxies in the void. M. Strauss and John Huchra announced the discovery of a further three galaxies in 1988, and Greg Aldering, G. Bothun, Robert P. Kirshner, and Ron Marzke announced the discovery of fifteen galaxies in 1989.

By 1997, the Boötes void was known to contain 60 galaxies.According to astronomer Greg Aldering, the scale of the void is such that "If the Milky Way had been in the center of the Boötes void, we wouldn't have known there were other galaxies until the 1960s."The Hercules Supercluster forms part of the near edge of the void.


Lyman-alpha Blob

In astronomy, a Lyman-alpha blob (LAB) is a huge concentration of a gas emitting the Lyman-alpha emission line.

LABs are some of the largest known individual objects in the Universe. Some of these gaseous structures are more than 400,000 light years across.

So far they have only been found in the high-redshift universe because of the ultraviolet nature of the Lyman-alpha emission line.

Since the Earth's atmosphere is very effective at filtering out UV photons, the Lyman-alpha photons must be redshifted in order to be transmitted through the atmosphere.

The most famous Lyman-alpha Blobs were discovered in 2000 by Steidel et al. Matsuda et al., using the Subaru Telescope of the National Astronomical Observatory of Japan extended the search for LABs and found over 30 new LABs in the original field of Steidel et al., although they were all smaller than the originals.

These LABs form a structure which is more than 200 million light-years in extent. It is currently unknown whether LABs trace overdensities of galaxies in the high-redshift universe (as high redshift radio galaxies — which also have extended Lyman-alpha halos — do, for example), nor which mechanism produces the Lyman-alpha emission line, or how the LABs are connected to the surrounding galaxies. Lyman-alpha Blobs may hold valuable clues for scientists to determine how galaxies are formed.



Type-cD Galaxies

The type-cD galaxy is a galaxy morphology classification, a subtype of type-D giant elliptical galaxy and have a large halo of stars.

They can be found near the centres of some rich galaxy clusters. They are also known as supergiant ellipticals or central dominant galaxies.

The cD-type is a classification in the Yerkes galaxy classification scheme, one of two Yerkes classifications still in common use, along with D-type.

The "c" in "cD" refers to the fact that the galaxies are very large, hence supergiant, while the "D" refers to the fact that the galaxies appear diffuse.

A backformation of "cD" is frequently used to mean central Dominant galaxy. cD's are also frequently considered the largest galaxies around. cD galaxies are similar to lenticular galaxies or elliptical galaxies, but many times larger, some having envelopes that exceed one million lightyears in radius.

They appear elliptical-like, with large low surface brightness envelopes. It is currently thought that cD's are the result of galaxy mergers. Some cD's have multiple galactic nuclei. cD galaxies are one of the types frequently found to be the Brightest cluster galaxy (BCG) of a cluster.

Many fossil group galaxies are similar to cD BCG galaxies, leading some to theorize that the cD results from the creation of a fossil group, and then the new cluster accumulating around the fossil group. However, cD's themselves are not found as field galaxies, unlike fossil groups. cD's form around 20% of BCGs.

cD galaxies are believed to grow via mergers of galaxies that spiral in to the center of a galaxy cluster, a theory first proposed by Herbert J. Rood in 1965. This "cannibalistic" mode of growth leads to the overwhelming diameter and luminosity of the cD's.

The second-brightest galaxy in the cluster is usually under-luminous, a consequence of its having been "eaten". Remains of "eaten" galaxies sometimes appear as a diffuse halo of gas and dust. This halo can be up to 3 million light years in diameter.

Dynamical friction is believed to play an important role in the formation of cD galaxies at the centres of galaxy clusters. This process begins when the motion of a large galaxy in a cluster attracts smaller galaxies and dark matter into a wake behind it. This over-density follows behind the larger galaxy and exerts a constant gravitational force on it, causing it to slow down.

As it loses kinetic energy, the large galaxy gradually spirals toward the centre of the cluster. Once there, the stars, gas, dust and dark matter of the large galaxy and its trailing galaxies will join with those of other galaxies who preceded them in the same fate. A giant or supergiant diffuse or elliptical galaxy will result from this accumulation. The centers of merged or merging galaxies can remain recognizable for long times, appearing as multiple "nuclei" of the cD galaxy.



OJ 287 Supermassive Black Hole

OJ 287 is a BL Lac object located 3.5 billion light years away that has produced quasi-periodic optical outbursts going back approximately 120 years, as first apparent on photographic plates from 1891.

It was first detected at radio wavelengths during the course of the Ohio Sky Survey.

Its central supermassive black hole is claimed to be the largest known, with a mass of 18 billion solar masses, more than six times the value calculated for the previous largest object.

The optical light curve shows that OJ 287 has a periodic variation of 11–12 years with a narrow double peak at maximum brightness.

This kind of variation suggests that an engine is a binary supermassive black hole where a smaller black hole with a mass of only 100 million MSun orbits the larger one with an observed 11-12 year orbital period.

The maximum brightness is obtained when the minor component moves through the accretion disk of the supermassive component at perinigricon.

The mass was calculated by a team led by Mauri Valtonen of Tuorla Observatory in Finland, and the group's results were presented to the public at the 211th meeting of the American Astronomical Society (AAS).

The timing of these outbursts allows the precession of the companion's elliptical orbit to be measured (39° per orbit), which allows the mass of the central black hole to be calculated using Albert Einstein's principles of General relativity.

The accuracy of this measurement has been called into question due to the limited number and precision of observed companion orbits, but the calculated value will be further refined using future measurements.

The companion's orbit is decaying via the emission of gravitational radiation and it is expected to merge with the central black hole within approximately 10,000 years.

The study has been published in the Astrophysical Journal. In order to reproduce all the known outbursts, a recent study shows that the rotation of the primary black hole has to be 28% of the maximum allowed rotation for a Kerr black hole.


Messier 87 (Supergiant Elliptical Galaxy)

Messier 87 is a supergiant elliptical galaxy. It was discovered in 1781 by French astronomer Charles Messier. The second brightest galaxy within the northern Virgo Cluster, it is located about 53.5 million light years away from Earth.

Unlike a disk-shaped spiral galaxy, Messier 87 has no distinctive dust lanes and it has an ellipsoidal shape.

At the core is a supermassive black hole, which forms the primary component of an active galactic nucleus that is a strong source of multiwavelength radiation, particularly radio waves.

A jet of energetic plasma originates at the core and extends out at least 5000 light-years. The stars in this galaxy form about one sixth of Messier 87's mass. They have a nearly spherical distribution, while the density of stars decreases with increasing distance from the core.

The galactic envelope extends out to a radius of about 490 kly, where it has been truncated. Between the stars is a diffuse interstellar medium of gas that has been chemically enriched by elements emitted from evolved stars. Any dust formed within the galaxy is destroyed within 46 million years by the X-ray emission from the core, although optical filaments of dust have been observed.

Orbiting the galaxy is an abnormally large population of about 12,000 globular clusters, compared to 150-200 globular clusters orbiting the Milky Way.Since this is one of the largest giant elliptical galaxies near Earth and is one of the brightest radio sources in the sky, Messier 87 is a popular target for both amateur astronomy observations and professional astronomy study.



VY Canis Majoris (Star)

VY Canis Majoris (VY CMa) is currently the largest known star and also one of the most luminous.

Located in the constellation Canis Major, it is a red hypergiant, between 1800 and 2100 solar radii, 8.4–9.8 astronomical units in radius, 3.063 billion km or 1.7 billion miles in diameter, and about 1.5 kiloparsecs (4,900 light years, 4.6×1016 km or 2.9×1016 mi) distant from Earth.

Unlike most hypergiant stars, which occur in either binary or multiple star systems, VY CMa is a single star.

It is categorized as a semiregular variable and has an estimated period of 2,000 days. It has an average density of 0.000005 to 0.000010 kg/m3.

Placed in our solar system, VY Canis Majoris's surface would extend beyond the orbit of Saturn, although the astrophysicists Philip Massey, Emily Levesque and Bertrand Plez disagree about the star's stated radius, suggesting it is smaller: merely 600 times the size of the Sun, extending past the orbit of Mars.

Stellar distances can be calculated by measuring parallaxes as the Earth orbits around the Sun. However, VY CMa has a tiny parallax with a high margin of error, which makes it unreliable to calculate its distance using this method. In 1976, Charles J. Lada and Mark J. Reid published the discovery of a bright-rimmed molecular cloud 15 minutes of arc east of VY CMa.

At the edge of the cloud bordered by the bright rim, an abrupt decrease in the CO emission and an increase in brightness of the 12CO emission were observed, indicating possible destruction of molecular material and enhanced heating at the cloud-rim interface, respectively.

Lada and Reid assumed the distance of the molecular cloud is approximately equal to that of the stars, which are members of open cluster NGC 2362, that ionize the rim. NGC 2362 has a distance of 1.5 ± 0.5 kiloparsecs as determined from its color-magnitude diagram.

VY CMa is projected onto the tip of the rim, suggesting its association with the molecular cloud. In addition to that, the velocity of the molecular cloud is very close to the velocity of the star. This further indicates the association of the star with the molecular cloud, and consequently with NGC 2362, which means VY CMa is also at a distance of 1.5 kpc.



NGC 3603-A1 (Binary Star System)

NGC 3603-A1 is a massive, double-eclipsing binary star system located in NGC 3603, about 20,000 light years from Earth. Its two component stars circle each other every 3.77 days. The mass of NGC 3603-A1a is 116 ± 31 solar masses and 89 ± 16 solar masses for NGC 3603-A1b.

This makes them the two most massive stars directly measured so far, i.e. their masses have been determined (using Keplerian orbits), and not estimated. Both show an emission-line spectrum (spectral type WN6h). The stars were identified and their masses calculated by a team from the Université de Montréal.


TrES-4b (Planet)

TrES-4b is an extrasolar planet discovered in 2006 and announced in 2007 by the Trans-Atlantic Exoplanet Survey using the transit method.

It is 1,400 light-years (430 pc) away in the constellation Hercules. TrES-4 orbits its primary star GSC 02620-00648 every 3.5 days and eclipses it when viewed from Earth.

It is 0.919 times as massive as Jupiter but 1.799 times the diameter, the largest planet ever found (next to WASP-17b, and that was in 1 May 2009), giving it an average density of only about 0.333 grams per cubic centimetre. This made TrES-4 both the largest known planet and the planet with the lowest known density at the time of its discovery.

TrES-4's orbital radius is 0.05091 AU, giving it a predicted surface temperature of about 1782 K. This by itself is not enough to explain the planet's low density, however. It is not currently known why TrES-4 is so large.

The probable cause is the proximity to a parent star that is 3–4 times more luminous than the Sun and the internal heat within the planet. A 2008 study concluded that the GSC 06200-00648 system (among others) is a binary star system allowing even more accurate determination of stellar and planetary parameters.



Ceres (Asteroid - Dwarf Planet)

Ceres, formally 1 Ceres, is the largest asteroid and the only dwarf planet in the inner Solar System. It was discovered on 1 January 1801 by Giuseppe Piazzi. It is named after Cerēs, the Roman goddess of growing plants, the harvest, and motherly love.

With a diameter of about 950 km (590 mi), Ceres is by far the largest and most massive body in the asteroid belt, and contains about a third of the belt's total mass. Observations have revealed that it is spherical, unlike the irregular shapes of smaller asteroids with lower gravity.

The Cererian surface is probably a mixture of water ice and various hydrated minerals such as carbonates and clays. Ceres appears to be differentiated into a rocky core and ice mantle, and may harbour an ocean of liquid water under its surface.

From the Earth, the apparent magnitude of Ceres ranges from 6.7 to 9.3, and hence even at its brightest it is still too dim to be seen with the naked eye except under extremely dark skies. On 27 September 2007, NASA launched the Dawn space probe to explore Vesta (2011–2012) and Ceres (2015).


While not as actively discussed as a potential home for extraterrestrial life as Mars or Europa, the potential presence of water ice has led some scientists to hypothesize that life may exist there, and that evidence for this could be found in hypothesized ejecta that could have come from Ceres to Earth.

It has also been hypothesized that biologically active ejecta from Earth could have landed on Ceres and colonized it.


Oort cloud

The Oort cloud is a hypothesized spherical cloud of comets which may lie roughly 50,000 AU, or nearly a light-year, from the Sun. This places the cloud at nearly a quarter of the distance to Proxima Centauri, the nearest star to the Sun.

The Kuiper belt and scattered disc, the other two reservoirs of trans-Neptunian objects, are less than one thousandth of the Oort cloud's distance.

The outer limit of the Oort cloud defines the cosmographical boundary of the Solar System and the region of the Sun's gravitational dominance. The Oort cloud is thought to comprise two separate regions: a spherical outer Oort cloud and a disc-shaped inner Oort cloud, or Hills cloud.

Objects in the Oort cloud are largely composed of ices, such as water, ammonia, and methane. Astronomers believe that the matter composing the Oort cloud formed closer to the Sun and was scattered far out into space by the gravitational effects of the giant planets early in the Solar System's evolution.

Although no confirmed direct observations of the Oort cloud have been made, astronomers believe that it is the source of all long-period and Halley-type comets entering the inner Solar System and many of the centaurs and Jupiter-family comets as well.

The outer Oort cloud is only loosely bound to the Solar System, and thus is easily affected by the gravitational pull both of passing stars and of the Milky Way Galaxy itself. These forces occasionally dislodge comets from their orbits within the cloud and send them towards the inner Solar System.

Based on their orbits, most of the short-period comets may come from the scattered disc, but some may still have originated from the Oort cloud. Although the Kuiper belt and the farther scattered disc have been observed and mapped, only four currently known trans-Neptunian objects—90377 Sedna, 2000 CR105, 2006 SQ372, and 2008 KV42—are considered possible members of the inner Oort cloud.