The Cosmos

“The man who graduates today and stops learning tomorrow is uneducated the day after.” - Newton Baker

The cosmos will always be a mystery to us. Each new discovery only adds to the mystery.

Here are some interesting fun facts about what is out there – courtesy of Facebook pages ‘Weird Facts’, ‘Unbelievable Facts’, ‘Today I Learned’, ‘Science and Facts’, ‘The Knowledge Factory’, ‘The Study Secrets’ etc… 

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Scientists think the final moments of a dying star could trigger a new Big Bang.

When a massive star runs out of nuclear fuel, gravity begins crushing it inward. According to the standard picture of physics, that collapse eventually forms a black hole, an object so dense that nothing, not even light, can escape its gravity.

But a new theoretical study proposes a far stranger possibility.

Physicists at Goethe University Frankfurt suggest that under certain conditions, a collapsing star may avoid becoming a black hole altogether. Instead, the collapse could trigger the formation of a tiny expanding universe deep inside the star.

The idea involves a hypothetical object called a gravastar, short for "gravitational vacuum star."

Unlike a black hole, a gravastar would contain a core dominated by dark energy, the mysterious force thought to make up roughly 68 percent of the universe's total energy content and drive the accelerating expansion of the cosmos.

As the star collapses, the researchers propose that a new region of spacetime could form within it. The conditions inside this region may resemble those that existed during the Big Bang that created our own universe 13.8 billion years ago.

That miniature universe would immediately begin expanding.

According to the team's calculations, the outward pressure generated by the expanding universe and its dark energy could become strong enough to counteract gravity's inward pull. Instead of collapsing into a singularity of infinite density, the star would stabilize as a gravastar.

One reason scientists find the idea intriguing is that black holes create major problems for physics. At their centers lie singularities, places where density becomes infinite and our current laws of physics break down completely.

Gravastars could potentially avoid that problem by replacing the singularity with an expanding universe.

The researchers emphasize that this does not mean black holes don't exist. Black holes remain one of the most successful predictions in astronomy and have been observed indirectly through their effects on stars, gas, and even gravitational waves. – A Facebook post by ‘From Quarks to Quasars’

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Three stars sit in a straight line across the night sky, close enough together that every civilization in human history pointed at them and made up a story. From Earth they look identical. They are anything but.

Those three points of light are Alnitak, Alnilam, and Mintaka, and the small orange dot at the bottom of this image is our Sun placed beside them for scale. It barely registers.

Alnilam sits in the middle and is the most luminous of the three. It shines with roughly 500,000 times the energy output of our Sun, making it one of the most intrinsically bright stars visible to the naked eye from anywhere on Earth. The catch is distance. All three belt stars sit between 800 and 1,300 light years away, which is why they appear as modest pinpricks rather than the cosmic furnaces they actually are.

Alnitak on the left is a multiple star system, with a brilliant blue supergiant at its center hot enough that most of its light pours out in ultraviolet wavelengths the human eye cannot detect. It is also responsible for illuminating the Flame Nebula sitting just beside it, a vast cloud of gas and dust that glows because Alnitak's radiation is energetic enough to ionize the hydrogen inside it.

Mintaka on the right is the faintest of the three and also sits closest to the celestial equator, which gave it practical value to ancient navigators. It rises and sets almost exactly due east and west regardless of where you are on Earth, making it one of the most reliable directional markers in the night sky for thousands of years before GPS existed.

Three stars that appear to be neighbors are not even close to each other in actual space. They share a direction from our perspective and nothing else.

That line in the sky that humans have traced since before recorded history is a trick of geometry. An accident of our particular vantage point on one small planet orbiting one very ordinary star that, next to any of these three, would not even be worth circling on a map. – A Facebook post by ‘@Astrophilesz'

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To understand the true scale of the Sun’s empire, start close and move outward. Light takes about 8 minutes to travel from the Sun to Earth. To reach Neptune, the farthest planet, it takes roughly 4 hours. To reach the heliopause, the boundary Voyager 1 crossed in 2012, it takes around 18 hours.

That already feels enormous. But the heliopause is not the true edge of the Sun’s influence. Beyond it, the Sun’s gravity continues to reach into deep space, holding distant icy objects across nearly 2 light-years. That means the Sun’s invisible domain stretches a significant fraction of the way toward Proxima Centauri, the nearest star system.

The planets, moons, asteroids, spacecraft, and even the heliopause itself are only the bright inner courtyard of something far larger. We celebrated the 18-hour boundary because Voyager crossed it, but the Sun’s real territory extends almost 2 light-years outward. One boundary is where the solar wind fades. The other is where the Sun’s gravity still quietly rules. – A Facebook post

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This is everything. Every single star you have ever seen in the night sky. Every galaxy every black hole every nebula every pulsar every quasar every planet every moon every asteroid every atom of matter that has ever existed in the 13.8 billion year history of reality — all of it fits inside this sphere 93 billion light years across.

We call it the Observable Universe — not because this is all that exists but because this is all the light that has had time to reach us since the Big Bang. Beyond this boundary there is almost certainly more universe — perhaps infinitely more — that we will never see because the universe is expanding faster than its light can reach us.

We exist on one pale blue dot orbiting one ordinary star in one ordinary galaxy among two trillion galaxies each containing hundreds of billions of stars in a universe so vast that the number of atoms in your body is small compared to the number of stars it contains. And yet here you are. Aware of all of it. Able to look up and wonder.

In 13.8 billion years of cosmic history the universe finally built something that could look back at itself and ask why. That is you. That has always been you. You are not separate from the universe. You are the universe experiencing itself. And that is the most extraordinary thing in all of existence. – A Facbeook post my ‘SkyMyst’

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The calcium in your bones was created inside a star that exploded billions of years before our Sun even existed. The iron in your blood was forged in the final seconds of a massive star's collapse into a supernova. The oxygen you are breathing right now was cooked inside the core of an ancient red giant that died long before Earth formed.

Every single atom heavier than hydrogen and helium in your entire body — every cell, every bone, every breath — was created inside a star that lived, burned, and violently died somewhere in our galaxy across billions of years. You did not arrive on Earth from somewhere else. You were built, piece by piece, from the literal remains of exploded stars.

The universe did not create you and then leave you alone in it. The universe rearranged itself, atom by atom, across billions of years, to become you. – A Facbeook post my ‘SkyMyst’

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