Our Sun is just one of about 200 billion stars in our galaxy.
Many other solar systems have multiple suns, while ours just has one. Our Sun is 864,000 miles in diameter and 10,000 degrees Fahrenheit on the surface.
So, if not for some cosmic event or quirk, Earth could have had two suns. But we don't.
Although it's a star – and our local star at that – our sun doesn't have a generally accepted and unique proper name in English. We English speakers always just call it the sun. You sometimes hear English-speakers use the name Sol for our sun.
Astronomers have announced the discovery of the 100th planet known to inhabit another solar system. The star is 100 light years from Earth in the southern constellation Grus, or The Crane. The planet, one and a half times the mass of Jupiter, has a roughly circular orbit, like those of the sun's family of planets.
However, if we once again assume that our own Milky Way Galaxy represents an average type of galaxy, we can calculate that there are roughly 150 billion stars born per year in the entire Universe. This corresponds to about 400 million stars born per day or 4800 stars per second!
The Milky Way has a mass of 1.5 trillion suns. Most of it is mysterious dark matter. - Vox.
Planet KOI-5Ab, for example, also has three suns in its skies, but it orbits around only one of them, gravitationally bound to that one star as it interacts with its neighbouring stars.
With no sunlight, photosynthesis would stop, but that would only kill some of the plants—there are some larger trees that can survive for decades without it. Within a few days, however, the temperatures would begin to drop, and any humans left on the planet's surface would die soon after.
Earth orbits our Sun, a star. Earth is the third planet from the Sun at a distance of about 93 million miles (150 million km).
Warmth: not too much and not too little
And we get the amount of warmth needed for humans, animals and plants to live. If the sun would go out, no life could survive on most of earth's surface within a few weeks. Water and air would freeze over into sheets of ice.
All plants would die and, eventually, all animals that rely on plants for food — including humans — would die, too. While some inventive humans might be able to survive on a Sun-less Earth for several days, months, or even years, life without the Sun would eventually prove to be impossible to maintain on Earth.
So our Sun is about halfway through its life. But don't worry. It still has about 5,000,000,000—five billion—years to go. When those five billion years are up, the Sun will become a red giant.
Stars like the Sun belong to a category called G-type main sequence stars or yellow dwarfs and have a lifetime of 9 to 10 billion years. If our Sun is 4.5 billion-years-old, we know that is currently at its halfway mark towards the end of its life.
Most stars have planets but exactly what proportion of stars have planets is uncertain because not all planets can yet be detected. That said it has been calculated that there is at least one planet on average per star. One in five Sun-like stars are expected to have an "Earth-sized" planet in the habitable zone.
In the outer Solar System, well beyond the orbit of Neptune and Pluto, a ninth planet may be waiting to be discovered. This 'ghost planet', nicknamed Planet 9 or Planet X, has never been observed directly, but peculiar goings-on in the space beyond Neptune hint tantalisingly at its existence.
Astronomers searching for our solar system's elusive Planet Nine — a theoretical world that may lurk deep in a cloud of icy rocks far beyond the orbit of Neptune — have come up short once again.
In the universe are billions of galaxies, in our galaxy are billions of planets, but there is Only One Earth – that's the message of this year's World Environment Day.
There Is Only One Sun
The word “sun” is often used to describe many multitudes of stars in our galaxy and beyond, but doing so is a misnomer. The Sun is the name of our star, just as Sirius is the brightest star in Canis Major.
Video: 'Three sun' phenomenon appears in China - YouTube.
Not one, but three suns were seen in Mohe town of Tuqiang in China for about 3 hours -- from 6:30 am to 9:30 am. This unusual event is a rare optical illusion caused by a natural phenomenon known as a 'sundog'.