Great mysteries of the Universe

[jw5]

Great mysteries of the Universe​

The Big Bang, the most widely-accepted theory for the origin of the Universe, took place 13.7 billion years ago. In one instant the Cosmos were created, and with this countless unsolved mysteries that have puzzled scientists for centuries. The questions are as intriguing as they are baffling: what's inside a black hole? Why does space roar? Are we alone?

 

[zhihau]

If energy is neither created nor destroyed in our current understanding of the observable universe, where did the energy for this big bang come from?

 

[jw5]

The Big Bang​

The Big Bang is the most widely accepted theory for the origin of the Universe. But what is the Big Bang?

 

[jw5]

What caused the Big Bang?​

Around 13.7 billion years ago, everything in the entire Universe was condensed in an infinitesimally small singularity, a point of infinite denseness and heat. Suddenly, from this mere dot, a huge explosion expanded space like a balloon. From a single atom, the Universe grew to bigger than a galaxy. It is still expanding today.

 

[jw5]

Mapping the Big Bang​

This image from the Wilkinson Microwave Anisotropy Probe (WMAP) satellite shows the first all-sky microwave image of the Universe soon after the Big Bang. It was published by a team of astronomers from NASA and Princeton University.

 

[jw5]

What is a light-year?​

Before we go any further, a word about light-years. For most space objects, light-years are used to describe their distance. A light-year is the distance light travels in one Earth year. And get this: one light-year is about nine trillion km (six trillion miles).

 

[jw5]

Dark matter​

Incredibly, the numerous planets, stars, galaxies, and everything else we can see make up less than 5% of the total Universe. The odd thing is that 26.8 % is a substance scientists label as "dark matter." It doesn't interact with light or visible matter, but can be detected through its gravitational influence on the movements and appearances of other objects in the Universe, for example stars or galaxies.

 

[zhihau]

What is beyond the edge of our observable universe?

 

[jw5]

Dark energy​

And what of the other 68% of the Universe? Cosmologists call this "dark energy," the mystery force that rules the Universe. This phenomenon overwhelmed gravity and gained control of the Universe about five billion years ago. It is invisible, fills all of space, and its repulsive gravity is speeding up the expansion of the Cosmos.

 

[kryonlight]

If energy is neither created nor destroyed in our current understanding of the observable universe, where did the energy for this big bang come from?

From the contraction of the previous universe.

 

[kryonlight]

What is beyond the edge of our observable universe?

Perhaps there is no edge, just like the mind. The mind is the universe. Without the mind, there is no universe.

 

[jw5]

Crab Nebula​

The Crab Nebula is a six-light-year-wide remnant of a supernova explosion. First observed by Chinese and other astronomers in the year 1054, it is 6,500 light-years from Earth.

 

[jw5]

Supernova​

Supernovae are violent stellar explosions that litter the Cosmos. One of the brightest, named by scientists as LMC N49 (pictured), is approximately 160,000 light-years from Earth.

 

[jw5]

Spiral galaxy​

Spiral galaxies consist of a flat, rotating disk containing stars, gas, and dust. These galaxy forms were originally described by American astronomer Edwin Hubble (1889–1953). Suitably, this image of Spiral Galaxy M81 is viewed from the Hubble Space Telescope.

 

[jw5]

Milky Way​

Our own galaxy, the Milky Way, is a barred spiral-shaped galaxy and includes our own solar system. The oldest stars in the Milky Way are nearly as ancient as the Universe itself, probably formed after the Big Bang.

 

[jw5]

Thousands of galaxies​

And there are thousands of galaxies out there. Even the small dots seen in this image are entire galaxies, and are about 13 billion light-years away.

 

[jw5]

Stellar jet​

Stellar jets are beams of ironized matter ejected from some astronomical objects, but usually produced by young stars still in the process of forming.

 

[jw5]

Black hole​

A black hole is a place in space where gravity is so strong that even light can't get out. This is because matter has been squeezed into a hugely compressed area. This happens, for example, when a star is dying. Scientists reckon there are millions of these cosmic bodies in our galaxy, but no one knows what they contain. This image is of a black hole in Messier 87, a supergiant elliptical galaxy in the constellation Virgo.

 

[jw5]

Exoplanets​

An exoplanet is a planet beyond our solar system. Most exoplanets orbit stars, but free-floating exoplanets, called rogue planets, orbit the galactic center in permanent darkness and are untethered to any star. Kepler-186f (pictured as an artist's concept), is the first exoplanet discovered in what scientists call the habitable zone—the region around the host star where the temperature is right for liquid water.

 

[jw5]

Kepler-452b​

Kepler-452b (sometimes nicknamed Earth 2.0 or Earth's Cousin) is an exoplanet orbiting the Sun-like star Kepler-452, about 1,400 light-years from Earth in the constellation Cygnus. It is the first potentially rocky super-Earth planet discovered orbiting within the habitable zone of a star very similar to the Sun.