Celestial Fireworks 

Resembling the puffs of smoke and sparks from fireworks in this image from NASA/ESA Hubble Space Telescope, these delicate filaments are actually sheets of debris from a stellar explosion in a neighboring galaxy.

Denoted N 49, or DEM L 190, this remnant is from a massive star that died in a supernova blast whose light would have reached Earth thousands of years ago. This filamentary material will eventually be recycled into building new generations of stars in the Large Magellanic Cloud. Our own Sun and planets are constructed from similar debris of supernovae that exploded in the Milky Way billions of years ago.

Credit: NASA/ESA and The Hubble Heritage Team (STScI/AURA)

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The Shape of the Universe that Sends Chills Down your Spine

According to Einstein’s theory of relativity, gravity and energy effect the shape of space.

You can imagine this by looking at gravity not as a ‘force’ but as a downwards indentation in space. If you take a towel and have it pulled flat then drop a bowling ball in the middle, the area around the bowling ball will have been pressed down. The Moon orbiting Earth is just following a straight trajectory around this downward curvature of space.

Energy does the opposite of gravity. It makes a positive curvature.

When you look at the big picture, you’ve got a universe whose overall shape is dictated by whether or not it’s got an overall positive, negative or zero amount of energy.

We know, thanks to measuring the gravity of regular matter, dark matter and the strange anti-gravitational force called 'dark energy’, that we can make an equation with energy on one side and gravity on the other.

This equation will tell us the shape of the universe.

A negative answer means our universe is shaped like a saddle. A positive one means our universe is shaped like a globe (closed). An answer of zero means the universe has flat geometry.

Want the mysterious part?

Scientists have found that the universe is somehow, shockingly *perfectly tuned*. The measured amount of dark energy combined with the average density of matter is approximately zero. Our universe is flat.

With a flat universe, a universe with a net total of zero energy, we have a case of an entire universe being created out of nothing.

Somehow the matter and gravitational energies that otherwise cancelled each other out in a state of 'zero-ness’ were separated. Our universe may have in fact been created out of nothing.

It gets more odd. If you were to add (which we can’t) a single gram of matter (just one gram) it totally changes the entire shape of the universe. Our universe would be a closed one that would end in a 'Big Crunch’ where all things collapse and fall into a singularity: a perfect opposite of the Big Bang.

Scientists don’t like it when things seem to be fine tuned. It usually means we’re missing something. This means that our universe is many times more incredible and mysterious than you may have ever imagined before…

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Wonderful. Chromoscope:

Ever wanted X-ray specs or super-human vision? Chromoscope lets you explore our Galaxy (the Milky Way) and the distant Universe in a range of wavelengths from gamma-rays to the longest radio waves.

From top to down:

Quick Tour of Chromoscope

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NASA Astronomy Picture of the Day 2015 August 4 

Virgo Cluster Galaxies 

Well over a thousand galaxies are known members of the Virgo Cluster, the closest large cluster of galaxies to our own local group. In fact, the galaxy cluster is difficult to appreciate all at once because it covers such a large area on the sky. This careful wide-field mosaic of telescopic images clearly records the central region of the Virgo Cluster through faint foreground dust clouds lingering above the plane of our own Milky Way galaxy. The cluster’s dominant giant elliptical galaxy M87, is just below and to the left of the frame center. To the right of M87 is a string of galaxies known as Markarian’s Chain. A closer examination of the image will reveal many Virgo cluster member galaxies as small fuzzy patches. 

The second picture shows galaxies using NGC catalog designations. Galaxies are also shown with Messier catalog numbers, including M84, M86, and prominent colorful spirals M88, M90, and M91. On average, Virgo Cluster galaxies are measured to be about 48 million light-years away. The Virgo Cluster distance has been used to give an important determination of the Hubble Constant and the scale of the Universe.

Olber’s Paradox, or why is the Sky Dark at Night?

In astrophysics and physical cosmology, Olbers’ paradox, named after the German astronomer Heinrich Wilhelm Olbers and also called the “dark night sky paradox”, is the argument that the darkness of the night sky conflicts with the assumption of an infinite and eternal static universe. The darkness of the night sky is one of the pieces of evidence for a non-static universe such as the Big Bang model. If the universe is static, homogeneous at a large scale, and populated by an infinite number of stars, any sight line from Earth must end at the (very bright) surface of a star, so the night sky should be completely bright. This contradicts the observed darkness of the night.

The paradox is that a static, infinitely old universe with an infinite number of stars distributed in an infinitely large space would be bright rather than dark. To show this, we divide the universe into a series of concentric shells, 1 light year thick. Thus, a certain number of stars will be in the shell 1,000,000,000 to 1,000,000,001 light years away. If the universe is homogeneous at a large scale, then there would be four times as many stars in a second shell between 2,000,000,000 to 2,000,000,001 light years away. However, the second shell is twice as far away, so each star in it would appear four times dimmer than the first shell. The total light received from the second shell is the same as the total light received from the first shell, so each shell of a given thickness will produce the same net amount of light regardless of how far away it is. That is, the light of each shell adds to the total amount. Thus the more shells, the more light. And with infinitely many shells there would be a bright night sky. Dark clouds could obstruct the light. But in that case the clouds would heat up, until they were as hot as stars, and then radiate the same amount of light. Kepler saw this as an argument for a finite observable universe, or at least for a finite number of stars. In general relativity theory, it is still possible for the paradox to hold in a finite universe: though the sky would not be infinitely bright, every point in the sky would still be like the surface of a star.

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Big Bang May Have Created a Mirror Universe Where Time Runs Backwards

By Tim De Chant

Why does time seem to move forward? It’s a riddle that’s puzzled physicists for well over a century, and they’ve come up with numerous theories to explain time’s arrow. The latest, though, suggests that while time moves forward in our universe, it may run backwards in another, mirror universe that was created on the “other side” of the Big Bang.

Two leading theories propose to explain the direction of time by way of the relatively uniform conditions of the Big Bang. At the very start, what is now the universe was homogeneously hot, so much so that matter didn’t really exist. It was all just a superheated soup. But as the universe expanded and cooled, stars, galaxies, planets, and other celestial bodies formed, birthing the universe’s irregular structure and raising its entropy.

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Triton, the largest moon of Neptune. Triton has a retrograde orbit (meaning that it orbits in the opposite direction of its parent planet), meaning that it was likely captured by Neptune from the Kuiper Belt. Triton’s orbit around Neptune is slowly shrinking, and it is believed that within the next 3.6 billion years, Triton will either be destroyed by the planet’s immense gravity, or else will turn into a Saturn-like ring system around Neptune.

NASA Astronomy Picture of the Day 2015 July 27 

Milky Way and Aurora over Antarctica 

It has been one of the better skies of this long night. In parts of Antarctica, not only is it winter, but the Sun can spend weeks below the horizon. At China’s Zhongshan Station, people sometimes venture out into the cold to photograph a spectacular night sky. 

The featured image from one such outing was taken in mid-July, just before the end of this polar night. Pointing up, the wide angle lens captured not only the ground at the bottom, but at the top as well. In the foreground is a colleague also taking pictures. In the distance, a spherical satellite receiver and several windmills are visible. Numerous stars dot the night sky, including Sirius and Canopus. Far in the background, stretching overhead from horizon to horizon, is the central band of our Milky Way Galaxy. Even further in the distance, visible as extended smudges near the top, are the Large and Small Magellanic Clouds, satellite galaxies near our huge Milky Way Galaxy.

The Search For Neutrons That Leak Into Our World From Other Universes

“Braneworld” theories predict that matter can leak into and out of other universes. So physicists are searching for the first evidence

One of the more exciting ideas in high energy physics is the possibility that our three-dimensional universe is embedded in a much bigger multidimensional cosmos. Physicists call these embedded universes “branes” and say that it should be possible for stuff from our brane to leak into other branes nearby and vice versa.

Today, Michael Sarrazin at the University of Namur in Belgium and a few pals say they have worked out to detect this leakage by measuring whether neutrons can bypass barriers by leaping into another brane and back again.

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