Explained: The Big Bang & The Universe

The Big Bang is a theory that explains how the universe expanded from a single point. The Big Bang occurred 13.7 billion years ago. All the matter, energy, and light; were all compacted into an infinitely dense point. The universe then expanded tremendously.

As the seconds passes; this condensed energy was spread out, and the forces such as gravity can into existence. Around 300,000 years after the Big Band, the universe was abundant with floating particles. These particles then slowly came to each other. The most simplest elements came into existence, most found was hydrogen (with 1 proton) and helium (with 2 protons).

Image Credit: NASA/WMAP Science Team
The different atoms were able to form and then these particles became more and more condensed. Soon matter was formed. The early stars were made up of very simple elements and so they had very short lifespans of only millions of years. But the nuclear fusion in the cores' of these early stars slowly created heavier elements; which when the star died, would become a part of a new star.

These stars were created in small groups and attracted other stars. These stars were grouped in irregular shapes. Then the different shapes merged to form the first galaxies.
Then as more galaxies formed, they became grouped in galaxy clusters, and then these clusters were contained in super clusters.

Today, scientist know about a force called dark energy. Dark energy acts like an anti-gravity and does the opposite of gravity. Dark energy is currently the cause of the expansion of the universe. The universe is expanding at an accelerating rate today.

With the discovery of dark energy, many scientist now believe the the universe will continue to expand forever and all of the matter in the universe will eventually decay within a trillion years.

Image Credit: NASA

Explained: The Sun

The Sun is a star located at the center of our solar system. The sun itself makes up 99.8% of our solar system's mass. The eight planets, three dwarf planets, and numerous other objects such as asteroids and comets orbit the sun. The Sun consists of mostly hydrogen and helium, which it uses as fuel to keep burning.



Currently, the Sun is 4.5 billion years old. When the Sun is 10 billion years old, it will expand to become a red giant. When is becomes red giant, it will be 2,000 times larger and 100 times brighter. Mercury and Venus will become engulfed by this growing Sun, but recent scientific models suggest that the Earth will be spared this awful fate and will move out to a farther orbit.

Since the Sun not a very large star, it will not die in the very large explosions known as a supernova. Instead, the Sun will slowly shed its outer layers which will become the beginnings of a planetary nebula (a cloud of gas). Then only the Sun's core will remain as a white dwarf. This white dwarf will be dramatically smaller than the current size of the sun, and will remain in space with just a white glow. This white dwarf will continue to glow for billions of years; all the while slowly becoming fainter.

The graphic below illustrates the Sun's size when it becomes a red giant.

An example of a planetary nebula is the Eskimo Nebula (NGC 2392). As you can see, the gas surrounds the white dwarf which is located in the center of the image. The white dwarf illuminates the nebula and gives it its beauty.

Image Credits: NASA, SPACE.com, Astronomy Picture of the Day (APOD)\

Alternate Article: The Sun's History & Future