Is the sun increasing or decreasing in size?

Question

I've heard people say both, kinda confusing,

Answer 1

The Sun oscillates in size, with a prominent 80-year period.

Answer 2

The Sun is about halfway through its main-sequence evolution, during which nuclear fusion reactions in its core fuse hydrogen into helium. Each second, more than 4 million tons of matter are converted into energy within the Sun's core, producing neutrinos and solar radiation. The Sun will spend a total of approximately 10 billion years as a main sequence star.

The Sun does not have enough mass to explode as a supernova. Instead, in 4-5 billion years, it will enter a red giant phase, its outer layers expanding as the hydrogen fuel in the core is consumed and the core contracts and heats up. Helium fusion will begin when the core temperature reaches around 100 MK, and will produce carbon and oxygen. While it is likely that the expansion of the outer layers of the Sun will reach the current position of Earth's orbit, recent research suggests that mass lost from the Sun earlier in its red giant phase will cause the Earth's orbit to move further out, preventing it from being engulfed. However, Earth's water will be boiled away and most of its atmosphere will escape into space.

Following the red giant phase, intense thermal pulsations will cause the Sun to throw off its outer layers, forming a planetary nebula. The only object that will remain after the outer layers are ejected is the extremely hot stellar core, which will slowly cool and fade as a white dwarf over many billions of years. This stellar evolution scenario is typical of low- to medium-mass stars.

Answer 3

it is a ball of burning fuel. The more it burns, the smaller it gets. so its decreasing in size. I've never heard increasing. They actually have time tables that have calculated how much longer the sun will last. Dont' worry thought, its a LONG time.

Answer 4

The sun is a great reactor. People often say stars are factories for heavier elements. In the process of forcing protons and neutrons together under the weight of the suns own gravity enery is released and the star shines. Thus because this is a crunching process the sun is getting gradually smaller.

Answer 5

well the son is decreasing it's size little by little, because the sun is a star and soon enough like any other star I'll die, but experts said that the sun its only in haft of its years. so you don't have to worry, i heard too that the universe is expanding and in some years the universe will have expand its limit and then shrink and the universes will crash each othe. one universe eating another. luckely i'll be dead when that happens.

Answer 6

As the Sun is decomposing (depleting it's Helium core), it's growing in diameter aka increasing with size. Here's something scary to think about...some astronomers say that the sun will swell so big and could possibly engulf the Earth...
Sunblock plz!

I hope this helps!

Answer 7

Right now it's increasing in size, but scientists predicted that about one million years later, our Sun will explode (the explosion is called a supernova) and after that, it will become a neutron star, black and out of energy. A star has many phases, and right now our star is in (i think it is called) the main phase.

Answer 8

Just so weams wont confuse you. My opinion is that it's doing neither yet. It's going to increase in size when its hydrogen fuel runs out. Then it will grow. Then when it turns into a white dwarf it will decrease in size and heat as well.

Answer 9

Increasing.

However it is decreasing in mass.

The sun is midway through its stable hydrogen burning phase known as the main sequence. But when the sun enters the red giant phase in around 5 billion years things are going to get a lot rougher in the Earth-moon system.

During the red giant phase the Sun will swell until its distended atmosphere reaches out to envelop the Earth and moon, which will both begin to be affected by gas drag -- the space through which they orbit will contain more molecules.

The moon is now moving away from Earth and by then will be in an orbit that's about 40 percent larger than today. It will be the first to warp under the Sun's influence.

"The moon's actual path is a wiggly line around the sun, with it moving faster when it is slightly farther out (at full moon) and more slowly when it is slightly closer (at new moon)," said Lee Anne Willson of Iowa State University. "So the gas drag is more effective at the farther part of the orbit and this will put the moon into an orbit where the new moon is closer to Earth than the full moon."

Willson's idea about the moon's demise, explained recently to SPACE.com, is an unpublished byproduct of her research into Earth's fate in the face of an expanding sun.

Moving away
Today, the moon is on average 239,000 miles (385,000 kilometers) away and has reached this point after a long and dramatic journey.

Earth's moon was born around 4.5 billion years ago in a titanic collision between our planet and a Mars-sized sibling, according to the leading theory. The enormous impact threw debris into orbit around the young Earth and from this maelstrom the Moon coalesced.

For the last few billion years the moon's gravity has been raising tides in Earth's oceans which the fast spinning Earth attempts to drag ahead of the sluggishly orbiting moon. The result is that the moon is being pushed away from Earth by 1.6 inches (4 centimeters) per year and our planet's rotation is slowing.

If left unabated, the moon would continue in its retreat until it would take about 47 days to orbit the Earth. Both Earth and moon would then keep the same faces permanently turned toward one another as Earth's spin would also have slowed to one rotation every 47 days.

Solar influence
The Sun's mutation into a red giant provides a huge stumbling block to the moon's getaway and is likely to ensure the moon ends its days the way it began; as a ring of Earth-girdling debris.

"The density and temperature both increase rapidly near the apparent surface (photosphere) of the future giant sun," Willson explained. As the Earth and moon near this blistering hot region, the drag caused by the sun's extended atmosphere will cause the moon's orbit to decay. The moon will swing ever closer to Earth until it reaches a point 11,470 miles (18,470 kilometers) above our planet, a point termed the Roche limit.

"Reaching the Roche limit means that the gravity holding it [the moon] together is weaker than the tidal forces acting to pull it apart," Willson said.

The moon will be torn to pieces and every crater, mountain, valley, footprint and flag will be scattered to form a spectacular 23,000-mile-diameter (37,000-kilometer) Saturn-like ring of debris above Earth's equator. The new rings will be short-lived. Theory dictates they'll eventually rain down onto Earth's surface.

"Particles of different masses will have different survival times; the smaller particles will be removed first, and the biggest ones last. Most of the ring particles would be gone by the time the Earth reaches the stellar photosphere," Willson said.

If the sun's photosphere reaches Earth, our planet too will experience drag and spiral into the Sun to be incinerated.

Possible out
There are possible natural alternatives, however.

If the sun as a red giant sloughs off enough material before Earth evaporates, our planet will be revealed from its stellar cocoon in a moon-less guise. Earth, robbed of its companion, would undertake a lonely vigil as the sun turns eventually into a stellar corpse called a white dwarf, fading to black over the ensuing trillions of years.

Alternatively, if the swelling sun loses 20 percent of its mass prior to it reaching our vicinity, both Earth and moon could be spared incineration and remain together facing each other for eternity. The actual outcome remains a theoretical uncertainty because no red giant star has been observed during this crucial phase.

Answer 10

I believe that it is decreasing. Eventually the sun will burn out. After billions of years is an awfuly long time.