What is a Wormhole?

A model of 'folded' space-time illustrates how a wormhole bridge might form with at least two mouths that are connected to a single throat or tube.Credit: edobric

A wormhole is a theoretical passage through space-time that could create shortcuts for long journeys across the universe. Wormholes are predicted by the theory of general relativity. But be wary: wormholes bring with them the dangers of sudden collapse, high radiation and dangerous contact with exotic matter.

Wormhole theory

In 1935, physicists Albert Einstein and Nathan Rosen used the theory of general relativity to propose the existence of "bridges" through space-time. These paths, called Einstein-Rosen bridges or wormholes, connect two different points in space-time, theoretically creating a shortcut that could reduce travel time and distance.

Wormholes contain two mouths, with a throat connecting the two. The mouths would most likely be spheroidal. The throat might be a straight stretch, but it could also wind around, taking a longer path than a more conventional route might require.

Einstein's theory of general relativity mathematically predicts the existence of wormholes, but none have been discovered to date. A negative mass wormhole might be spotted by the way its gravity affects light that passes by.

Certain solutions of general relativity allow for the existence of wormholes where the mouth of each is a black hole. However, a naturally occurring black hole, formed by the collapse of a dying star, does not by itself create a wormhole.

Through the wormhole

Science fiction is filled with tales of traveling through wormholes. But the reality of such travel is more complicated, and not just because we've yet to spot one.

The first problem is size. Primordial wormholes are predicted to exist on microscopic levels,
about 10–33 centimeters. However, as the universe expands, it is possible that some may have been stretched to larger sizes.

Another problem comes from stability. The predicted Einstein-Rosen wormholes would be useless for travel because they collapse quickly. But more recent research found that a wormhole containing "exotic" matter could stay open and unchanging for longer periods of time.

Exotic matter, which should not be confused with dark matter or antimatter, contains negative energy density and a large negative pressure. Such matter has only been seen in the behavior of certain vacuum states as part of quantum field theory.

If a wormhole contained sufficient exotic matter, whether naturally occurring or artificially added, it could theoretically be used as a method of sending information or travelers through space.

Wormholes may not only connect two separate regions within the universe, they could also connect two different universes. Similarly, some scientists have conjectured that if one mouth of a wormhole is moved in a specific manner, it could allow for time travel. However, British cosmologist Stephen Hawking has argued that such use is not possible.

Although adding exotic matter to a wormhole might stabilize it to the point that human passengers could travel safely through it, there is still the possibility that the addition of "regular" matter would be sufficient to destabilize the portal.

Today's technology is insufficient to enlarge or stabilize wormholes, even if they could be found. However, scientists continue to explore the concept as a method of space travel with the hope that technology will eventually be able to utilize them.

Watch the video here

— Nola Taylor Redd, SPACE.com Contributor

If You Are Moving at the Speed of a Bullet and Shoot It Backwards, What Happens?

Photo by Niels Noordhoek / Wikimedia Commons / CC-BY-SA 3.0

Let’s say that you are traveling along at about 300 km/h. For some reason, you decide to do some target shooting in order to pass the time. So you take out your trusty gun, or cannon, or what-have-you, and you point it backwards. In this case, you are firing in the opposite direction that you are traveling (after all, you don’t want to shoot the pilot). As luck would have it, your weapon fires at the exact same speed that you are traveling. So, you are flying along at 300 km/h and you are about to shoot a bullet/cannon/whatever in the opposite direction at 300 km/h.

What happens to the projectile? Does it go shooting off in the opposite direction? Does it go anywhere? It may seem like a silly question, but it is important to any aft firing aircrafts.
There are a few different answers to this question, depending on the specific conditions; however, the short answer is:

–You are traveling along a path at 300 km/h. We will call this “B”

–You fire in the opposite direction at 300 km/h. We will call this “-B”

–So you are traveling at B and you fire at –B

–And –B + B = 0, so the bullet should fall straight down. That’s right; you pull the trigger, the projectile plummets straight down.

What would this look like? For an onlooker, someone who is standing still and watching you fly by, they will see you take aim and pull the trigger; however, the bullet leaving the weapon will appear to fall straight down as the plane pulls away from around it (I am assuming that the back of the plane is open, and that the observer has windows to see all of this happen).

However, in reality, things are a bit more complicated. First, even if the projectile can travel 300 km/h in the opposite direction, it will need a bit of time to reach that speed. In short, when you pull the trigger, the bullet won’t immediately be traveling at 300km/h in the opposite direction (-B). Since the bullet takes time to accelerate, when you pull the trigger, the bullet in the chamber will have to speed up to reach –B and cancel out the effects of B.

So in reality, the projectile would not fall straight down; it would a short distance after the point at which you shot it.

The short answer also assumes that there is no air resistance. And of course, there will be air resistance. Also, in a gun, rifle, or similar weapon, the projectile will spin. Both the air resistance and spin will cause the projectile to go off course a bit. In other words, it won’t go back perfectly straight, and will end up shooting off course a bit (which means no falling straight down).

That said, assuming that you give up the whole target shooting idea and just want the projectile to fall straight down, it is *possible* to get the projectile to do this – it is just exceedingly hard as the conditions have to be nearly perfect. Unfortunately, I don’t have the time to establish perfect conditions…but others did. To see this in action, check out the MythBusters video.

Along these same lines, if you shoot forward at 300 km/h, then the projectile will be moving forward at 600 km/h relative to the ground (again, this is not taking any contributing factors into consideration)

Video>>https://www.youtube.com/watch?v=BLuI118nhzc

Source:- quarksandquasars.com

Introducing: The Newest Member of the “Ten Largest Stars in the Known Universe”

Image Credit: NASA/JPL-Caltech (Source)

Stars, like people, come in a variety of flavors. Firstly, there are red-dwarfs. The name itself conveys important information about the stars belonging to this class. They are small (hence the “dwarf” part) and red in color (hence the “red” part). Then, we have medium-sized stars. Our sun is one such star. These stars vary in spectral classification, but the Sun is technically called a “yellow-dwarf.” The next rung in the ladder of star types contains the massive, extremely hot, and very bright stars. These are commonly known as “super-giants.” Using the ladder metaphor, if super-giants are at the top, the star we’re about to discuss is practically in low-Earth orbit.

MEET HR 5171:

The European Southern Observatory JUST announced new findings related to a star that is so large, it ranks among the ten largest stars in the known universe. The star in question, called HR 517S (other names include V766 Cen and HD 119796), has many notable features. It’s a high-mass variable star and it has a much smaller partner. Astronomers have known about its small companion for a while now, but it wasn’t until very recently that they knew just how much influence this tiny star has on its much larger counterpart.

ing the ESO’s “Very Large Telescope Interferometer” (VLTI), a team of international researchers deployed a technique called interferometry, which essentially makes use of the light collected by several different telescopes. When combined, astronomers can peer further through the veil of space and see things in unprecedented clarity. Such was the case with this star system.

THE RESULTS:

The team learned that not only was the tiny partner much closer to the primary star than expected (giving the system the likeness of a peanut), but the star is basically providing HR 517S with a seemingly endless buffet of stellar material. The celestial cannibalism going on in the system has given HR 517S the juice it needs to power its incredibly rapid expansion, which has resulted in the star growing to become more than 1300 times larger than the Sun in diameter (and it’s more than a million times more luminous).Us

If you’re having a hard time envisioning just how large that is, let’s compare its size to that of Betelgeuse (the star famous for being one of the largest of its kind). Betelgeuse is FIFTY percent less massive than HR 517S. As stated above, these facts make the star one of the largest stars in the known universe (it comes in on the top ten list).

Similarly, it is the largest star belonging to its spectral classification group, which is the ”yellow hyper-giant” classification. Stars of this type generally are the biggest and brightest stars in the universe. They also grow much more unstable than stars that belong to the super-giant group as they evolve, thus they are quite a bit more energetic and can generate a much more extensive atmosphere (this makes it easier to pin down key details about the star’s interior and external structure). Over all, this research has given us more insight into this spectral class than any other research done before.

LASTLY:

The system is located approximately 12 000 light-years from Earth in the Centauri constellation. Given how immensely huge it this star is, one would think it would stick out like a sore thumb. In reality, the star is hardly perceptible to the naked eye, unless you know exactly what you’re looking for. This likely won’t change in the years to come, despite the fact that the star is unstable not long for this universe (in astronomical terms). Soon, it will reach the end of its life-span, going out in a spectacular supernova blast. Ultimately, its relative anonymity is a testament to just how large the universe is. Plus, it reminds us that much is left to still be discovered.

Source : Wikipedia, From Quarks to Quasars

A Man Far from Home: Astronaut Bruce McCandless II

Astronaut Bruce McCandless II via NASA

In this haunting image, we see a solitary astronaut, Bruce McCandless II, hovering in the inky darkness of space. Beneath him, the world spins slowly on, along with all the people and all the things that we’ve ever known. The photograph was captured during McCandless trip aboard the space shuttle Challenger on February 12, 1984.

During this jaunt out into space, McCandless ventured farther than any previous astronaut before him.

This accomplishment was ultimately made possible by the Manned Maneuvering Unit (MMU), which allows astronauts to make untethered free flights away from their spacecrafts (this was the first ever untethered free flight using the MMU). This device was used in several different maneuvering missions, culminating with STS-51-A, in which the propulsion unit was used to retrieve two communication satellites that did not reach their proper orbits because of faulty propulsion module. The astronauts were able to safely retrieve the satellites and return them to Earth.

After the Space Shuttle Challenger disaster, the MMU was judged too risky for further use, as there would be little anyone could do for an astronaut if the MMU suffered a major malfunction.

Although McCandless looks like a small speck drifting a long way from the safe confines of his craft, he is actually only 320 feet (100 meters) from the Orbiter. Still, going into orbit is relatively risky business by itself, using a nitrogen jet propelled backpack to leave the safety of your craft and drift several hundred feet out into open space is probably a bit beyond the scope of what most would call rational.

But of course, McCandless didn’t just hop on and take the MMU for a spin. He spent some time maneuvering near Challenger before voyaging out. You are probably a bit more familiar with the image of McCandless that is posted below. This close up image shows him just a short distance from the craft and in a position that seems far less perilous.

Astronaut Bruce McCandless II via NASA

Being the first human to take a free floating ride though space is pretty awesome; however, McCandless is known for far more than being the astronaut to travel farthest from any link to planet Earth. For starters, he graduated second in a class of 899 from Annapolis, and over the course of his career, he received a host of awards and honors. Most notable are his Legion of Merit in 1988 and the Department of Defense Distinguished Service Medal in 1985. And that is just the start; McCandless has a host of other awards and honors attributed to him.

So despite the awesome sublimity of this image–the astounding and awe inspiring horror of being adrift miles above the Earth–the overall take away for me is simply, “look what one can do with a bit of hard work and courage.” True, sometimes (many times) humanity is depressing, but often, we are also terribly glorious.

source:-fromquarksandquasars.com

Scientists Measure Spin of Extremely Distant Supermassive Black Hole

Image via NASA/Chandra/ESA

Black holes are some of the most amazing structures in the universe. They are truly the tyrants of the cosmos—consuming moons, planets, stars, and entire solar systems without batting an eye.

However, black holes are more than just cosmic vacuum cleaners; they are fast, terrible fast. In fact, astronomers recently discovered a black hole that is spinning at half the speed of light. Yes, that’s 50% the speed of light, or a staggering 93,141 miles per a second (149,896 km/sec).

The black hole in question lies at the center of a quasar, RX J1131-1231, which can be found drifting from the cosmos some 6 billion light-years from Earth. The fact that scientists were able to measure the spin of this monster is particularly noteworthy as 6 billion light-years is rather far away, even for our most modern telescopes. However, scientists were able to get a detailed reading, all thanks to a giant elliptical galaxystationed about halfway between our own little world and RX J1131-1231.

Image Credit: NASA/ESA

This galaxy bends the light that is given off by the black hole (this process is known called “gravitational lensing”). The bending focuses the distant light of the black hole, making it easier to measure. Of course, once a black hole consumes matter, it is essentially lost to us. So black holes don’t give off light per say. Rather, light (X-rays) are created by the bands of dust and gas that surround black holes (these are called accretion disks). The X-rays are produced when the accretion disk creates a multimillion-degree cloud (called a corona) near the black hole.

The scientists in charge of the study found that the X-rays in the cloud surrounding RX J1131-1231 were coming from a region that is so close to the black hole the the black hole must be spinning extremely rapidly, otherwise this heated cloud would not be able to survive at such a small radius.

Ultimately, the speed at which this black hole spins is notable as it corresponds to models that predict how black holes develop and grow. Our projections indicate that, the more matter that black holes consume, the faster they spin. RX J1131-1231 is spinning rather rapidly (to put it mildly) and it is consuming a lot of material, about the equivalent of one sun each year. In the end, these two facts come together to support whatcomputer models currently predict about black hole development.

However, this black hole is far from the fastest. There is another, NGC1365, which was clocked at a mind-blowing 85% the speed of light. NGC1365 is approximately 60 million light-years from Earth, at the center of a spiral galaxy. What’s more, the black hole is some 1.9 million miles (3.2 million km) in diameter and it has a mass two million times that of our Sun. However, RX J1131-1231 is much younger than NGC1365, and so it has had far less time to speed up .

Ultimately, this is the first time that scientists have been able to use gravitational lensing to get accurate readings from a black hole this distant, so it’s rather exciting to consider what future research of these supermassive beasts might uncover.

Ref:-space.com

-Thar Htet Aung

နာဆာဟာ ဂ်ဳပီတာၿဂိဳလ္ရဲ႕ အရံလျဖစ္တဲ့ ယူရိုပါ လေပၚကို ဘာေၾကာင့္ သြားခ်င္ေနရတာလဲ???

Jupiter's Moon, Europa

ကမာၻေပၚမွာ ေရဟာ အပင္မ်ားအပါအ၀င္ သက္ရွိအားလံုးတို႔ကို အဓိက ေထာက္ပံ့ေပးေနတဲ့ မရွိမျဖစ္တဲ့ အရာျဖစ္ပါတယ္။ ဆိုလိုတာကေတာ့ ေရရွိရန္ သက္ရွိရွိဖို႔အတြက္ ျဖစ္ႏိုင္ေခ် အရမ္းမ်ားသြားမွာေပါ့။ ကမာၻဆိုတာဟာ တကယ္ေတာ့ စၾကာ၀ဠာဟင္းလင္းျပင္ထဲက မွိန္ျပျပအျပာေရာင္အစက္ကေလးတစ္စက္(Pale Blue Dot) ေလးပါ။ ဒီကမာၻေပၚမွာ ကၽြနု္ပ္တို႔လူသားေတြအပါအ၀င္ သက္ရွိမ်ိဳးစိပ္ေပါင္း သန္းခ်ီေနထိုင္ေနၾကတာ အခုဆိုရင္ ႏွစ္သန္းေပါင္း ၂ ဘီလီယံခန္႔ရွိပါၿပီ။ က်ယ္ေျပာလွတဲ့စၾကာ၀ဠာႀကီးထဲမွာ ကၽြန္ေတာ္တို႔ကမာၻလိုမ်ိဳးၿဂိဳလ္ေတြ၊ ၿပီးေတာ့ အျခားသက္ရွိေတြရွိမေနႏိုင္ဘူးလား။ ဒီေမးခြန္းကေတာ့ ယခုခ်ိန္ထိ အတိအက်မေျဖႏိုင္ေသးပဲ သိပၸံပညာရွင္ေတြနဲ႔ သိပၸံစကား၀ိုင္းေတြအလယ္မွာ အျငင္းပြားေနဆဲျဖစ္ပါတယ္။ ဆိုလိုတာကေတာ့ ရွိႏိုင္တယ္လို႔လဲ အတိအက် မေျပာႏိုင္၊ မရွိဘူးလို႔လဲ တပ္အပ္မေျပာႏိုင္တဲ့ အေျခအေနပါ။

>>ဖာမီ ၏ အရႈတ္အေထြး(Fermi's Paradox)<<

-ကၽြႏု္တို႔ရဲ႕ ေနမင္းႀကီးဟာ ငယ္ရြယ္ေသးတဲ့ ၾကယ္ေလးတစ္လံုးပါ။ ကၽြန္ုပ္တို႔ေနမင္းႀကီးထက္ ႏွစ္ေပါင္းဘီလီယံခ်ီ အသက္ႀကီးတဲ့ၾကယ္ေတြ ဘီလီယံခ်ီၿပီး ဂလက္ဆီထဲမွာ ရွိပါေသးတယ္။

-တစ္ခ်ိဳ႕ေသာ ၾကယ္ေတြမွာ ကၽြန္ေတာ္တို႔ကမာၻလို ဆင္တူတဲ့ ၿဂိဳလ္ေတြရွိႏိုင္ပါေသးတယ္။ ကမာၻလို ၿဂိဳလ္အမ်ိဳးအစားဟာ အသိညဏ္ရွိတဲ့ သက္ရွိေတြအတြက္ စံပံုစံၿဂိဳလ္ျဖစ္တယ္ဆိုရင္ ထုိၿဂိဳလ္ေတြေပၚမွာလဲ ကၽြႏု္တို႔လို သက္ရွိေတြရွိေနႏိုင္ပါတယ္။

-တစ္ခ်ိဳ႔ေသာၿဂိဳဳလ္ေတြဟာ ကမာၻထက္ႏွစ္သန္းခ်ီေစာျဖစ္ခဲ့တယ္ဆိုလွ်င္ ထိုၿဂိဳလ္ေပၚက သက္ရွိေတြဟာ ယခုကၽြႏ္ုပ္တို႔ ေလ့လာႀကိဳးစားေနဆဲျဖစ္တဲ့ စၾကာ၀ဠာအတြင္း ခရီးသြားလာျခင္း နည္းပညာကို ေတြ႕ရွိၿပီးျဖစ္ပါလိမ့္မယ္။

-ဒီလိုဆိုရင္ ထိုသက္ရွိေတြဟာ စၾကာ၀ဠာနဲ႔ ဂလက္ဆီအတြင္း ေနရာေတာ္ေတာ္မ်ားမ်ားကို နယ္ခ်ဲ႕ၿပီးသားျဖစ္ပါလိမ့္မယ္။ ကမာၻအပါအ၀င္ေပါ့။

ဒီမွာ ယခုအေပၚက စဥ္းစားပံုလမ္းေၾကာင္းအတိုင္းစဥ္းစားၿပီးေတာ့ အန္ရစ္ကို ဖာမီ(Enrico Fermi) ဆိုတဲ့ သိပၸံပညာရွင္က ေမးခြန္းတစ္ခု ထုတ္လိုက္ပါတယ္။

"WHERE IS EVERYBODY?"

ေမးခြနး္ေလးကေတာ့ ရွင္းရွင္းေလးပါ။ ဒါေပမယ့္ သိပၸံနယ္ပယ္ႀကီးတစ္ခုလံုးကို လႈပ္ခက္သြားေစခဲ့တာေတာ့ ယေန႔ထိပါပဲ။

ထို႔ေနာက္ သိပၸံပညာရွင္တို႔ရဲ႕ အသိုင္းအ၀ိုင္းမွာ ဒီေမးခြန္းကို တိတိက်က်ေျဖႏိုင္ဖို႔ ႀကိဳးစားလာခဲ့ၾကပါတယ္။ စၾကာ၀ဠာထဲတြင္ အျခားသက္ရွိမ်ားရွိေသာ္လဲ ကၽြႏု္ပ္တို႔လူသားမ်ားက အသိညဏ္အရွိဆံုးလား။ ထို႔ေၾကာင့္ အျခားသက္ရွိမ်ား ကမာၻေပၚေရာက္မလာေသးတာလား။ သို႔ေသာ္........ UFO ေခၚ ပန္းကန္ျပားပ်ံအခ်ိဳ႕အားေတြ႕ျမင္ရျခင္းႏွင့္ အျခား အဆင့္ျမင့္လြန္းေသာ အေျဖရွာမရသည့္ ေခတ္ဦးက နည္းပညာမ်ား(ဥပမာ-ပိရစ္မစ္မ်ား၊ နက္စ္ကာလိုင္းမ်ား၊ ဧရာမေက်ာက္တုန္းရုပ္ႀကီးမ်ား စသျဖင့္) တို႔သည္ ကမာၻအ၀န္း၌ ေပၚေပါက္ေနသည္။ အျခားသက္ရွိမ်ား ကမာၻေပၚေရာက္ခဲ့ေသာ္လဲ (၀ါ) ေရာက္ရွိေနေသာ္လဲ အဘယ့္ေၾကာင့္ ကၽြႏ္ုပ္တို႔ႏွင့္ အဆက္အသြယ္မလုပ္သနည္း။ အဘယ့္ေၾကာင့္ တစ္ခါတစ္ရံမွသာ ပုန္းလွ်ိဳး၀ွက္လွ်ိုးျမင္ရသနည္း။

ဖာမီ၏ ေမးခြန္းကိုေျဖႏိုင္ရန္၊ ရွင္းလင္းသြားေစရန္ ဦးစြာကၽြန္ပ္တို႕သည္ အျခားသက္ရွိတစ္မ်ိဳးကို ေတြ႕ႏိုင္ရန္ အလြန္လိုအပ္ေနၿပီျဖစ္သည္။ ထို႔ေၾကာင့္ အျခားကမာၻမွ သက္ရွိမ်ားကို ရွာပံုေတာ္ဖြင့္ေနသည္မွာလဲ ႏွစ္ေပါင္း အေတာ္အတန္ၾကာခဲ့ၿပီျဖစ္သည္။

>>ေမွ်ာ္လင့္ခ်က္ေရာင္ျခည္သန္းလာၿပီ<<

Europa and Earth, water consistent comparison

ယခုအခါတြင္ နာဆာသည္ ဂ်ဳပီတာ၏ အရံလျဖစ္ေသာ ယူရိုပါ(Europa) ေပၚတြင္ ေရမ်ား ပိုလွ်ံစြာရွိေနေၾကာင္း ေထာက္လွမ္းမိခဲ့သည္။ ထိုၿဂိဳလ္အရံလေပၚတြင္ရွိေသာ ေရ၏ ပမာဏမွာ ကၽြႏ္ုပ္တို႔ ကမာၻထက္ပင္ ၂ ဆခန္႕ရွိေနသည္။(ပံုကိုၾကည့္ပါရန္) ထို႔ေၾကာင့္ ထိုၿဂိဳလ္ေပၚတြင္ ကၽြႏု္ပ္တို႔ႏွင့္ ဆင္တူေသာ သက္ရွိမ်ား ရွိေနႏိုင္သည္။ ကမာၻေပၚမွာ သက္ရွိတို႔သည္လည္း ေရမွပင္ အစပ်ိဳးျဖစ္တည္ခဲ့ေသာေၾကာင့္ ထိုၿဂိဳလ္ေပၚသြားရသည္မွာ ကမာၻဦးအခ်ိန္ကိုျပန္သြားသကဲ့သို႔ပင္ ျဖစ္ေနလိမ့္မည္။ ထို႔ေၾကာင့္ နာဆာသည္ ထို ယူရိုပါ ေပၚသို႔သြားေရာက္ရန္ အထူးပင္ စိတ္အားထက္သန္ေနသည္။



စၾကာ၀ဠာအတြင္း သက္ရွိရွာပံုေတာ္၏ ေျခတစ္လွမ္းတိုးလိုက္သည္ဟုပဲ ကၽြန္ေတာ္ထင္မိသည္။ ကၽြန္ေတာ္မေသခင္ ဖာမီ ၏ ေမးခြန္းအေျဖ ကိုသိသြားလိုပါေၾကာင္း............................

-သာထက္ေအာင္