THE SUN

THE SUN

5.0 to 4.7 billion years ago: Gas, dust, and matter from exploded stars eventually coalesced through gravity into a swirling mass known as the "solar nebula", which was cantered around the newly formed sun. The swirling dust eventually coalesced from gravity to form the planets.

4.6 billion to 4.2 billion years ago: Earth has formed from collisions of blobs of matter, planetesimals (small rocky astronomical objects thought to have orbited the Sun in the early stages of the solar system before coalescing with others to form the planets) and comet bombardment. Much of the entire planet was still molten, but an early crust starts to form the first solid surface.

4.1 billion to present: Surface water, marine life, oxygenated atmosphere, snowball earth, life on land, tectonic movements, asteroid impacts, floods, volcanism, human life and civilization.

Before we had a Solar System, there was just a giant cloud of cold molecular hydrogen. And then something happened to the cloud that caused it to collapse. Perhaps it was the interaction with a passing star, or maybe the shockwave from a nearby supernova triggered the collapse. After that, the cloud began to collapse because of its collective gravity.

As the gas and dust collected together, it started to spin and flatten out. Most of the mass collected in the center, while the rest spun out into the flattened proto planetary disk (here’s where the planets, moons, and asteroids formed). The Sun ignited fusion in its core once it had enough temperature and pressure.

The Sun has a diameter of 1.392 million KM. Antares star is approximately 1.113 billion KM in diameter about 1000 times more than the sun. This means that about 512 million Suns would fit inside Antares.

The nearest star to the Sun is Proxima Century which is 4.24 light years away. If our sun were the size of a penny, the nearest star, would be another penny 350 miles away.

The largest known star is VY Canis Majoris which is about 2,100 times larger than our Sun which would mean 9,261Million Suns would fit inside. VY Canis Majoris has a radius of about 2,100 solar radii.

Antares has a radius of about 800 solar radii.

So Vy Canis Majoris is about 2.625 times larger than Antares.

Star name	Solar radii (Sun = 1)
VY Canis Majoris	1,800–2,100; once thought to be a star so large that it contradicted stellar evolutionary theory, improved measurements have brought it down to size
VV Cephei A	1,600–1,900
V838 Monocerotis	1,570 ± 400
Mu Cephei (Herschel's "Garnet Star")	1,650
WOH G64	1,540
V354 Cephei	1,520
KY Cygni	1,420–2,850
KW Sagittarii	1,460
RW Cephei	1,260–1,610
Betelgeuse (Alpha Orionis)	1,180
Antares (Alpha Scorpii)	800

How old is the Sun? Actually it's middle-aged. Scientists use a technique called radiometric dating to assess the age of planets. The sun was formed about 4,600,000,000 (4.6 billion) years ago and we expect it to carry on pretty much as it is now for a few billion years yet -When the Sun is about 7 billion years old it will slowly start to change and will become bigger and cooler. By the time it is 10 billion years old it will have changed into a red giant and its atmosphere will stretch out to near where the Earth is today.

We can touch the sun then by sitting on Earth!