36 civilizations in the Milky Way

MILKY WAY GALAXY COULD BE HOME TO 36 ACTIVE, INTELLIGENT CIVILISATIONS BESIDES HUMANS, STUDY SUGGESTS  firstpost.com

Tom Westby and Christopher Conselice published a study estimating that there were or were 36 civilizations throughout the Milky Way Galaxy (it was not said what the level of technological advancement would be, so it could very well be ancient or medieval).

The distance between them would be 17,000 light-years on average (with current technology it would take us millions of years to travel there, given that up to the nearest star, Proxima Centauri, 4 light-years away, would take 6300 years).

Communication with another civilization 17,000 light-years away would take 34,000 years, 17,000 years for our signal to reach that planet, and another 17,000 years for their signal to reach our planet.

It cannot be discussed as on Messenger or as in Star Trek through video broadcasts from light years.

There is a possibility that civilization will disappear until the signal arrives, decay technologically or change completely culturally, or have been destroyed or invaded by another aggressive civilization and not find the same civilization as before.

It is impossible to communicate with other extraterrestrial civilizations through space, unless we find a way to transmit signals through wormholes / portals and reach the planet directly in a matter of seconds.

But for that we would need centuries or even millennia to study the universe, matter and dark energy, and invent a technology to open wormholes through which to transmit information, signals and messages.

Maybe signals from an advanced civilization already crossed the Earth's orbit 17,000 years ago ......... when humans were primitive hunter-gatherers hunting bison, settling in North America, inventing pottery for the first time in China and domesticated the pig.

Maybe 5,000 years ago when people built the pyramids or 800 years ago when Europe was in the Middle Ages, in the age of castles, inquisitions and knights.

Maybe there have never been any signals past the Earth about how vast the galaxy is.

Erik Verlinde's New Theory Of Gravity Tries To Explain Dark Matter

Collage of six cluster collisions with dark matter maps. The clusters were observed in a study of how dark matter in clusters of galaxies behaves when the clusters collide Photo: wikipedia.org

Although gravity is the most familiar force of the universe, it is a thorny problem for theoretical physicists as it has long defied its inclusion in quantum mechanics. Another problem is dark matter only interacts with gravity and also defies the standard model of particle physics.

Professor Erik Verlinde, a researcher from the Delta Institute for Theoretical Physics in Amsterdam, believes that gravity is not an actual force of the universe but an effect due to the increasing entropy of the universe. In his latest paper, which is available on arXiv but is yet to be peer-reviewed, the scientist claimed that this “emergent” (and not real) force of gravity has a dark component that behaves like dark matter.

Mysterious Universe: Super Force Mysterious Universe

Photo: quantumdiaries.org

"We have evidence that this new view of gravity actually agrees with the observations," said Verlinde in a statement. "At large scales, it seems, gravity just doesn't behave the way Einstein's theory predicts."

Erik Verlinde, Theoretical Physicist at Amsterdam

Quite the bold statement from the researcher, especially since it has been shown that Einstein’s general relativity agrees quite well with large-scale observations. In the paper, Verlinde admits that the idea of this dark gravitational component needs to answer several questions before it is able to be as successful at explaining the early universe and large scale cosmology as the current theory of gravity.

The theory of entropic gravity was first proposed by Verlinde in a paper in 2010 and published in the Journal of High Energy Physics in 2011. The proposed idea was welcomed by some as a novel approach to the problem of gravity in quantum mechanics.

Verlinde's new theory of gravity passes first test Phys.org

Others were more skeptical and devised ways to see if gravity could really be an emergent phenomenon. In 2011, Archil Kobakhidze of the University of Melbourne looked at how gravity affects fundamental particles. His findings strongly support the idea that gravity is a real force.

Entropic gravity is appealing because it is able to reproduce the laws of Newtonian gravitation and Einstein field equations from the first thermodynamics and quantum mechanical principles, but the theory itself doesn’t make predictions so it can’t be falsified.

Einstein’s general relativity is constantly being tested, and discoveries like gravitational waves have only strengthened its role as the best theory of gravity we currently possess.


Other articles on the same theme:

• Dark Energy vs. Dark Matter

• The universe: Reading the future from the distant past

• Astronomers issued a shocking theory about the universe: 'The Universe is Flat!'

• Young galaxies "born" at least 50 stars annually

Story source:
The above post is reprinted from materials provided by IFL Science . Note: Materials may be edited for content and length.

Astronomers issued a shocking theory about the universe: 'The Universe is Flat!'

The local geometry of the universe is determined by whether the density parameter Ω is greater than, less than, or equal to 1.

From top to bottom: a spherical universe with Ω > 1, a hyperbolic universe with Ω < 1, and a flat universe with Ω = 1. Note that these depictions of two-dimensional surfaces are merely easily visualizable analogs to the 3-dimensional structure of (local) space. photo: wikipedia.org

The universe is flat, has said recently, but there are many subtleties behind this assertion. How can we tell the Universe form? It means that a 3D object to be flat? May be other interesting things to say?

Hubble Eyes Hanny's Voorwerp - Universe Today

For starters, we must define the notion of "flat". Screen that look is flat and the earth is curved, for example, but we can calculate mathematically how this? A plausible answer refers to the parallel lines, for as you draw two parallel on a sheet of paper and will continue, they will be forever parallel, it is the more common definition of parallel lines. 

43K Galaxies: Most Complete 3D Map of the Universe Ever

However, this exercise must be repeated in relation to the Earth's surface, each heading towards the north, and the shape of the curve of the Earth makes them meet at a time. Earth curbaţiei opposite that of a saddle, the surface of which parallel lines move away from each other. So you can measure "flat" structure using only parallels.

Slices through the Sloan Digital Sky Survey 3-dimensional map of the distribution of galaxies with the Earth at the center, an example of an experimental attempt to catalog the observable universe. photo: wikipedia.org

However, determining the shape of the universe is a matter of cosmology, and he has a plurality of deformation, there are masses of energy and there is a close correlation between time and space. Have you ever wondered what the difference between a sphere and a cylinder? Use your schools which have drawn two parallel lines and manufactured a cylinder. Meanwhile observed parallel lines: they remain, indeed, parallel to the cylinder is flat.


This happens because there is a clear distinction between geometry and topography, and as he studied the geometry of the universe is very careful, not topography. But if the universe is indeed flat, this is met in a very distant place, which can not be observed by astronomers, because they never observed galaxies and the CMB identical intersecting.

The universe is flat, has said recently, but there are many subtleties behind this assertion. How can we tell the Universe form? It means that a 3D object to be flat? May be other interesting things to say?

For starters, we must define the notion of "flat". Screen that look is flat and the earth is curved, for example, but we can calculate mathematically how this? A plausible answer refers to the parallel lines, for as you draw two parallel on a sheet of paper and will continue, they will be forever parallel, it is the more common definition of parallel lines. However, this exercise must be repeated in relation to the Earth's surface, each heading towards the north, and the shape of the curve of the Earth makes them meet at a time. Earth curbaţiei opposite that of a saddle, the surface of which parallel lines move away from each other. So you can measure "flat" structure using only parallels.

Mapping the Universe, containing the circular map of the universe

However, determining the shape of the universe is a matter of cosmology, and he has a plurality of deformation, there are masses of energy and there is a close correlation between time and space. Have you ever wondered what the difference between a sphere and a cylinder? Use your schools which have drawn two parallel lines and manufactured a cylinder. Meanwhile observed parallel lines: they remain, indeed, parallel to the cylinder is flat.

Mapping the Universe: Space, Time, and Discoveries

This happens because there is a clear distinction between geometry and topography, and as he studied the geometry of the universe is very careful, not topography. But if the universe is indeed flat, this is met in a very distant place, which can not be observed by astronomers, because they never observed galaxies and the CMB identical intersecting

Other articles on the same theme:

• It was created the most complex map of the Milky Way . It shows that our galaxy is much more extensive than previously thought

• The universe: Reading the future from the distant past

• 10 fascinating planets outside the Solar System

• Young galaxies "born" at least 50 stars annually

Story source:

The above post is reprinted from materials provided by Space . Note: Materials may be edited for content and length.

It was created the most complex map of the Milky Way . It shows that our galaxy is much more extensive than previously thought

Milky Way  (Foto:spaceandintelligence.com) 

Researchers say they underestimated the number of stars existing within our galaxy.

European Space Agency released the most detailed map to date of the Milky Way. The digital representation depicting the positions of no less than 1.142 billion stars, is the first product of Gaia space observatory, launched three years ago. Among the identified cosmic objects there were about 400 million stars unknown, which means that our galaxy is much more extensive than previously thought in the moment.

,, This map released today the extraordinary density of the stars studied by Gaia indicates and confirms that space observatory has collected valuable information in its first year of activity. Although current data are preliminary, we will do our best to put them to the community of astronomers to use them as soon as possible, "says Timo Prussia, a researcher involved in the project Gaia.

Map presented by the European Space Agency experts is the result of the cumulative effort of not less than 450 researchers. Comparing observations with the help of Gaia observer to those shown in the Hipparcos and Tycho catalogs-2, scientists have been able to estimate distances and movements carried about 2 million stars. The result: the most comprehensive picture of the movement of the stars obtained so far.

Map Milky Way obtained by European astronomers (Photo: sciencealert.com/ESA/Gaia/DPAC)

Gaia Space Observatory is located about 1.5 million kilometers from Earth and is equipped with a 1 miliiard pixels capable of measuring the diameter of a human hair from a distance of 1,000 kilometers. Vehicle mission will last nearly 5 years and aims at mapping the Milky Way, which astronomers assume that accommodates no less than 100 billion stars.

Although experts are confident that the Centre will not be able to analyze these cosmic objects over 5 years, they say, for now, the result is very good, given that Gaia has begun to map the proper since July 2014.


,, It appears we underestimated the number of stars. We think there are about 2-2.5 billion, "said van Leeuwen Floor, researcher at Cambridge University.

Other articles on the same theme:

• The Milky Way's Halo Spins With The Galaxy
• Dark Energy vs. Dark Matter
• 4,000 confirmed exoplanets similar to Earth
• The universe: Reading the future from the distant past

Story source: 

 

The above post is reprinted from materials provided by sciencealert.com . Note: Materials may be edited for content and length.

The Milky Way's Halo Spins With The Galaxy

Astronomers from the University of Michigan have, for the first time, measured the speed at which the Milky Way halo is rotating, a discovery that could provide new clues on how galaxies form and evolve.

Our galaxy is surrounded by a gaseous halo that extends for many hundreds of thousands of light-years from the center. It has a mass comparable to the Milky Way itself and it was believed to be still, compared to our quickly rotating galaxy.

"This flies in the face of expectations," lead author Edmund Hodges-Kluck said in a statement. "People just assumed that the disk of the Milky Way spins while this enormous reservoir of hot gas is stationary – but that is wrong. This hot gas reservoir is rotating as well, just not quite as fast as the disk."

The gas in the halo is incredibly hot, millions of degrees, but very spread out so it's difficult to estimate how quickly it's moving. The researchers had to carefully detect movement as the gas moved in front of very bright extragalactic sources, like active supermassive black holes and quasars.

In a paper published in the Astrophysical Journal, they reported that the gas is moving at about 180 kilometers per second (400,000 mph), which is only slightly slower than the rotational velocity at the rim of the Milky Way (240 km/s, 540,000 mph).

"The rotation of the hot halo is an incredible clue to how the Milky Way formed," continued Hodges-Kluck. "It tells us that this hot atmosphere is the original source of a lot of the matter in the disk."

Galaxies are believed to have formed when intergalactic materials began to fall into the large gravitational wells formed by dark matter. The rotation of the halo tells us how quickly the material must fall towards the center, and also how quickly the Milky Way came together.

"Now that we know about the rotation, theorists will begin to use this to learn how our Milky Way galaxy formed – and its eventual destiny," added Professor Joel Bregman, co-author of the study.

Source: iflscience

Dark Energy vs. Dark Matter: What The Universe is Made Of

Dark Energy vs. Dark Matter

While dark energy repels, dark matter attracts. And dark matter’s influence shows up even in individual galaxies, while dark energy acts only on the scale of the entire universe

Our universe may contain 100 billion galaxies, each with billions of stars, great clouds of gas and dust, and perhaps scads of planets and moons and other little bits of cosmic flotsam. The stars produce an abundance of energy, from radio waves to X-rays, which streak across the universe at the speed of light.

Yet everything that we can see is like the tip of the cosmic iceberg — it accounts for only about four percent of the total mass and energy in the universe.

About one-quarter of the universe consists of dark matter, which releases no detectable energy, but which exerts a gravitational pull on all the visible matter in the universe.

Because of the names, it’s easy to confuse dark matter and dark energy. And while they may be related, their effects are quite different. In brief, dark matter attracts, dark energy repels. While dark matter pulls matter inward, dark energy pushes it outward. Also, while dark energy shows itself only on the largest cosmic scale, dark matter exerts its influence on individual galaxies as well as the universe at large.

In fact, astronomers discovered dark matter while studying the outer regions of our galaxy, the Milky Way.


A ring of possible dark matter highlights this Hubble Space Telescope image of a distant galaxy cluster. [NASA/ESA/M.J. Jee/H. Ford (Johns Hopkins)]

The Milky Way is shaped like a disk that is about 100,000 light-years across. The stars in this disk all orbit the center of the galaxy. The laws of gravity say that the stars that are closest to the center of the galaxy — which is also its center of mass — should move faster than those out on the galaxy’s edge.

Yet when astronomers measured stars all across the galaxy, they found that they all orbit the center of the galaxy at about the same speed. This suggests that something outside the galaxy’s disk is tugging at the stars: dark matter.

Calculations show that a vast "halo" of dark matter surrounds the Milky Way. The halo may be 10 times as massive as the bright disk, so it exerts a strong gravitational pull.

The same effect is seen in many other galaxies. And clusters of galaxies show exactly the same thing — their gravity is far stronger than the combined pull of all their visible stars and gas clouds.

Scientists shed light on mystery of dark matter HeritageDaily

Are dark matter and dark energy related? No one knows. The leading theory says that dark matter consists of a type of subatomic particle that has not yet been detected, although upcoming experiments with the world’s most powerful particle accelerator may reveal its presence. Dark energy may have its own particle, although there is little evidence of one.

Instead, dark matter and dark energy appear to be competing forces in our universe. The only things they seem to have in common is that both were forged in the Big Bang, and both remain mysterious.

Other articles on the same theme:

• New Theory Of Gravity Tries To Explain Dark Matter

• What form does the atomic nucleus? New discovery may explain the mysteries of the Universe.

• A new theory on the Creation of the Universe, disprove the Big Bang

• Vera Rubin, the American astronomer who confirmed the existence of dark matter, died at the age of 88 years.

Source: hetdex