Star, Galaxy - Current Affairs Questions and Answers

ANSWER: 2 trillion

Explanation:
The universe contains around 2 trillion galaxies, ten times more than previously thought according to a new study.

Astronomers have sought to study how much the number of galaxies are in the observable universe equals.

Scientists have used images from Hubble Space Telescope to estimate that the universe contains 100-200 billion galaxies.

Presently, technology permits just 10 percent of these galaxies to be studied and remaining 90 percent will be seen once bigger and better telescopes are developed.

Pencil beam images of deep space from telescopes around the world, and especially from the Hubble telescope, were converted into 3D maps.

This permits the density of the galaxies as well as volume of one small region of space following another to be studied.

Like an intergalactic archaeological dig, the research has enabled the team to establish how many galaxies have been missed.

Results of the study are based on the measurement of number of observed galaxies at different epochs through the universe history.

The scientists have examined how many galaxies there were at a given epoch they found that were significantly more at earlier times.

When the universe was a few billion years old, there were 10 times as many galaxies in a given volume of space as there were within a similar volume in present times.

Most galaxies are low mass systems with masses similar to those of the satellite galaxies surrounding the Milky Way.

Over 13.7 billion years of cosmic evolution since the Big Bang saw galaxies that have been growing through star formation and merger with other galaxies.

This suggests significant evolution must have occurred to reduce their number through extensive merging of systems.

ANSWER: Vela

Explanation:
An international team of astronomers has found one of the universe's biggest superclusters of galaxies near the Milky Way.

Researchers said the Vela supercluster, which had previously gone undetected as it was hidden by stars and dust in the Milky Way, was a huge mass that influenced the motion of our galaxy.

The gravity of the Vela supercluster may explain the difference between the measured motion of the Milky Way through space and the motion predicted from the distribution of previously mapped galaxies.

Anglo-Australian Telescope was used to measure distances for many galaxies to confirm earlier predictions that Vela was a supercluster.

ANSWER: Wide Field Infrared Survey Explorer

Explanation:
For the first time, astronomers have documented the process through which radiation is expelled from black holes- holding the key to how galaxies are formed using the WISE telescope.

• The NASA’s Wide-field Infrared Survey Explorer (WISE) telescope studied how supermassive black holes – concentrations of mass the size of hundreds of thousands or even millions of suns, with gravity so powerful even light cannot escape – exist in the centres of most galaxies.
• When an object is absorbed by a black hole, not all of the contents are consumed – instead it emits a vast “belch” of intense radiation,
• This is a blinding bright whip of energy known as a tidal disruption flare, which wipes out everything in its path.
• Using images from the WISE telescope, launched in 2009, which can measure the infrared emissions of cosmic dust, the US scientists have found at least three black holes surrounded by the radiation-charged cosmic dust
• Chinese have found another one.
• “This is the first time we have clearly seen the infrared light echoes from multiple tidal disruption events,” say researchers
• Belches create new stars and form the shape of the galaxy
• Scientists say this is how mechanics of process operated while the universe was first formed 14 billion years ago

ANSWER: Galaxy as large as Milky Way but very less luminosity

Explanation:

• An ultra-diffuse galaxy (UDG) is an extremely-low-density galaxy. Such a galaxy may have the same size as the Milky Way but a visible star count of only 1%. Their lack of luminosity is due to the lack of star-forming gas in the galaxy.
• Ultra diffuse galaxies are large like the Milky Way — which is much bigger than most — but they glow as dimly as mere dwarf galaxies. They came to attention only last year.

ANSWER: Same

Explanation:
In a first move of its kind, a team of astronomers have discovered that the Milky Way’s halo is spinning in the same direction and at comparable speed as the disk of the galaxy providing potential explanation for the galaxy’s missing mass.

• People just assumed that the disk of the Milky Way spins while this enormous reservoir of hot has is stationary, but this is incorrect.
• This hot gas reservoir is rotating as well, not quite as fast as the disk.
• New knowledge reveals how individual atoms have assembled into stars, planets and galaxies like our own and what the future has in store for these galaxies.
• Researchers used the archival data obtained by XMM Newton- an ESA telescope.
• As per the team, the galaxy’s hot gaseous halo is several times larger than the Milky Way disk and composed of ionised plasma.
• As the motion produces a shift in the wavelength of light, researchers measured such shifts around the sky using lines of very hot oxygen.
• Line shifts measured by the researchers displayed that the halo pains of the galaxy in the same direction as the disk of the Milky Way and at similar speed- 643737.6 mph for the halo versus 869045.76 kmph for the disk.

ANSWER: UGC 1382

Explanation:
Scientists have uncovered a bizarre Frankenstein galaxy formed from parts of other galaxies some 250 million light years away.

• The new study showcases the secret of UGC 1382, a galaxy once thought to be old, small and typical.
• Scientists using data from NASA telescopes and other observatories have discovered the galaxy is 10 times bigger than earlier thought.
• Unlike most galaxies, its insides are younger than its outsides.
• The rare galaxy formed is able to survive as it has been located in a small neighbourhood of the universe which is relatively isolated.

ANSWER: Hydrogen

Explanation:
Scientists have detected a faint signal emitted by the hydrogen gas in a galaxy more than 5 billion light years away. This measurement is almost double the previous record of distance.

• Scientists have detected a faint signal emitted by hydrogen gas in a galaxy more than 5 billion light years away
• This measurement is double the previous record of distance
• The signals would begin their journey before the planet even existed
• Incredible measurement is almost is double the previous record of distance
• Signals would begin their journey even before the planet existed and after 5 billion years of traveling through space without hitting anything
• The team also found that the distant galaxy contains billions of young massive stars surrounded by clouds of hydrogen gas
• Till now radio telescopes have only been able to detect the emission signal of hydrogen from new galaxies
• Following upgrade of the VLA, scientists have been directly able to measure atomic hydrogen in a galaxy this far from earth

ANSWER: GN-z11

Explanation:
Scientists have discovered the farthest thing seen by humans and the galaxy 13.4 billion light years away has been spotted by Hubble telescope. New galaxy could lead to changes in understanding how the universe has evolved. Distance from the galaxy is measured through the splitting of light into colours it is made of. As the universe is expanding, distant objects are associated with the red colour spectrum- the greater the red shift, the further away the galaxy is. Newly discovered gallery GN z-11 has beaten EGSY8p7 which had a red shift of 8.68. The new galaxy has a red shift of 11.1. Distance means light left the galaxy when the universe was just forming. Light came 400 million years after the universe commenced 1.8 billion years ago. GN-z11 is 25 times smaller than the Milky Way yet it is throwing out stars 20 times faster than our universe.

ANSWER: J021659-044920

Explanation:
Astronomers working at National Centre for Radio Astrophysics have discovered a rare galaxy of massive size located close to 9 billion light years away. Such galaxies with extremely large 'radio size' are called giant radio galaxies or GRG. Galaxy was known by the name J021659-044920 discovered using the Giant Metrewave Radio Telescope led by IISER pune Scientist P. Tamhane.

ANSWER: MOO J1142+1527

Explanation:
Astronomers discovered a giant galaxy in the remote parts of the universe said to be the most massive structure found 8.5 billion light years away. This cluster was spotted using NASA's Spitzer Space Telescope and Wide-field Infrared Survey Explorer (WISE). These clusters are galaxies bound together by gravity. As they acquire new members, clusters increase in size over time. The galaxy cluster called Massive Overdense Object (MOO) J1142+1527 was present 8.5 billion years ago, long before Earth was formed.