What makes the core of the Sun collapse when it runs out of hydrogen, and how does that trigger the red giant phase?

 When the Sun's core runs out of hydrogen, it won't quietly fade away. It will violently collapse under its own gravity, igniting a ferocious new firestorm that expands to swallow Earth.

Right now, the Sun is in a delicate, billions-of-years-long standoff called hydrostatic equilibrium. The immense gravity of its mass is constantly trying to crush it inward, while the nuclear fusion of hydrogen into helium in its core creates an outward radiation pressure that holds that gravity at bay.

In about five billion years, that standoff will end. The Sun will run out of hydrogen in its very center, leaving behind a dense, inert core of helium.

Without hydrogen fusion to generate outward pressure, the core can no longer resist gravity. The helium core immediately begins to collapse in on itself under the crushing weight of the star's outer layers. As the core compresses, it becomes denser and hotter, driven by the laws of thermodynamics.

This collapsing, superheated core triggers the red giant phase.

While the core itself is out of hydrogen, there is still plenty of unfused hydrogen in the layers immediately outside it. The intense heat radiating from the collapsing helium core warms this surrounding boundary until it reaches millions of degrees. Suddenly, this layer ignites, creating a hydrogen burning shell around the dead core.

This shell burning is actually fiercer and faster than the Sun's current core fusion. The newly ignited shell unleashes more energy than the core ever did, creating an outward radiation pressure that overpowers the star's gravity.

This pressure forces the Sun's outer layers outward, expanding the star to hundreds of times its original size. As the outer gases are pushed millions of miles into space, they expand and lose heat. The surface temperature drops, causing the star's light to shift from yellow-white to a glowing, cooler red. The collapsed core and the hyperactive burning shell have transformed the Sun into a red giant, pushing its surface out into the inner solar system.

A cross-section comparing the internal structure of a solar-type main-sequence star with the expanded layers and hydrogen-burning shell of a red giant. Photo by ESO is licensed under CC BY 4.0.

Is the sun really god?

• Living : Sun is treated as Pratyaksha devata ( living God) in Hinduism.
• Rama : Hindu religion associate him with Lord Rama - an incarnation of Narayan or Mahavishnu.

• Vaman : Lord Vaman is treated among 12 Adityas, sons of Aditi ji and Sage Kashyapa
• Shiva : Sun is treated as right eye of Lord Shiva -the most compassionate God.

• Highest : Hindus treat Gayatri Mantra as the highest mantra or sacred chant.
• King : Vedic astrology treats Sun as king of all planets.
• Life : Sun lights gives nourishment to all
• Serotonin Sun develops serotonin an important harmane in human body.

• Yoga : Surya Namaskar is treated among the best exercises in Patanjali Yoga Sutras.
• Soul : Sun is treated as Atma (soul) that is witness to all human deeds.

• Prayer : Pranam to Shri Ghrini Surya Aditya ! (3 sacred names of Lord Sun)
• Pic Credits : Google Images / Web

What are some mind-blowing facts about the Sun?

 The sunlight warming your skin today took just eight minutes to travel 93 million miles. But those exact photons spent tens of thousands of years trapped inside the Sun's core.

Born of nuclear fusion, a photon must constantly collide with densely packed atoms in the radiative zone, bouncing in a "random walk" that can last up to 100,000 years before finally reaching the surface and launching into space.

If an atmosphere existed between Earth and the Sun, the acoustic waves generated by the Sun's convective layer would reach Earth as a constant, crushing roar. Heliophysicists calculate that this roar would register on the ground at roughly 100 to 125 decibels—about the volume of a chainsaw or a rock concert, despite the Sun being nearly a hundred million miles away.

The Sun also sheds mass at an astronomical rate. Every second, it converts 600 million tons of hydrogen into helium. In this process, about 4 million tons of matter is converted directly into energy, while another 1.5 million tons is blown away as solar wind. Despite losing 5.5 million tons of mass every second, the Sun is so vast that it has lost only about 0.05% of its total mass over its entire 4.6 billion-year lifespan.

To visualize this scale, consider a coronal mass ejection (CME)—an eruption of magnetized plasma that bursts from the solar atmosphere.

A coronal mass ejection erupts from the Sun, with Earth superimposed to scale in the lower left. Photo by NASA Goddard Space Flight Center is licensed under CC BY 2.0.

As shown in the image, a single solar prominence dwarfs the entire planet, rendering Earth a tiny speck next to a towering loop of plasma. The Sun accounts for 99.86% of all mass in the solar system, meaning everything else—every planet, asteroid, moon, and living organism—is made from the leftover dust of its creation.

Why doesn't Sun Pictures do a movie with Ajith?

Ajith breaks into a rash whenever the Karunanidhi family is involved 😁 (And Maaran by extension)

He had a LOT OF PROBLEMS in 2010–2011 during the time he signed for Mankatha

He was literally paid his fees in Bags of Cash delivered in the night

He was summoned five times by IT to explain rumours about Mankatha when a truck with ₹17 Crore cash was seized near VGP and the driver said it was to deliver funds to Venkat Prabhu for Mankatha

He was forced to attend an event and when he refused , he was literally told that “If he didn't he had to be looking over his shoulder all the time”

He was asked to APOLOGISE to the CM of Tamilnadu after his angry speech and Rajini too had to apologise for clapping

So Ajith would never work with Sun Pictures

Of course circumstances can change but for the moment he has VERY BAD EXPERIENCES WITH DMK

The exact opposite is true with Vijay and Kamal

Vijay has had most of his issues with ADMK including major distruptions during Kaththi, Thalaivaa and Sarkar

Kamal had his terrible moment in 2013 during Vishwaroopam

If Europa is 780M km from the sun, how come it has liquid water? Shouldn't it be frozen?

 Europa may be far from the Sun, but it orbits in a very busy neighborhood.

Europa orbits Jupiter, so there is naturally some tidal flexing from that, but the other 3 large Gallilean moons (Io, Ganymede & Callisto) orbit close by each with their own orbit period. Each time they pass, these moons also tug on Europa, pulling it to and fro and flexing the moon generating heat.

The surface water of Europa evaporates then freezes solid when exposed to the vacuum, so Europa is covered with a layer of ice, but underneath the ice is believed to be one of the largest liquid water oceans in the solar system.

A secondary source of heat may be Jupiter’s powerful magnetic field which may agitate molecules within Europa enough to cause an increase in temperature. Europa’s neighbor moon, Io, is closer to Jupiter and receives even more energy from Jupiter’s magnetic field, running a powerful flux tube between Io and the giant planet.

All of this tidal heating from the gravitational interaction with Jupiter and its other large moons keeps enough water liquid under the ice to be measured by radar reflection and sensors from probes like Galileo.

Is it true that Jupiter is so big that it doesn't orbit the sun?

 Yes!

Jupiter, the largest planet in our solar system. It's so massive that 1,300 Earths could fit inside it. Jupiter is 2.5 times more massive than all the other planets in our solar system combined!

This is our little earth compared to Jupiter:

Jupiter is so large that the center of gravity of the sun and Jupiter is outside the sun, although it is extremely close to the sun's surface.

So the Sun and Jupiter both orbit around their center of gravity, also known as the barycenter.

The barycenter is the center of mass of two or more bodies orbiting each other and is the point around which the bodies orbit.

Technically Jupiter orbits the center of the sun and Jupiter is outside the sun.

So yes! Jupiter is so big that it doesn't orbit the sun. Fascinating!

Now, other planets in the solar system are so small that the center of gravity of the sun and a planet like Earth are located inside the sun. (Even very close to the center of the sun.)

So it looks like other planets are orbiting the center of the sun.

Source: Baricentro - Wikipedia

To understand this, you can also imagine turning a child around like this:

(It could be dangerous. Just imagine.)

The center of gravity of you and the baby would be somewhere very close to your feet. So you're spinning almost in the same spot, but the baby is orbiting you. This is exactly what happens with the sun and the other planets.

By the way, this is how two stars with nearly the same mass orbit around their common center of gravity in a binary star system:

Center of gravity - Wikipedia

What will the last humans see and think when the Sun melts the Earth?

Surprisingly, the existence of humans, or their biological or robotic descendants, is projected to extend Earth's lifespan before it is melted by the aging Sun. This disregards any human efforts to extend the habitability of our planet by building shades or altering Earth’s orbit.

Our system is already 4.5 billion years old, and it’s roughly halfway through its life before it becomes a tiny white dwarf. Before it happens, it will expand and become a red giant. It will then absorb Mercury and Venus. The fate of Earth is less certain because, as the Sun expands, it will also lose mass, causing the orbits of the remaining planets to expand. Most likely, Earth will be devoured in a manner similar to that of Venus. There is a small chance that it will become a burnt ember of what it was if it's spared this sorry fate.

In the run-up to this, many natural systems that make our planet habitable will fail one by one. For decades, we thought we might have only 600 to 800 million years before Earth becomes uninhabitable, and many answers on Quora still repeat this, but recently, we have made some progress in knowing with greater certainty the real fate of our planet. There is even a chance that we might have up to 1.5 billion years before it becomes uninhabitable, assuming that humans or our biological or robotic descendants are gone.

It is projected that as hundreds of millions of years pass from the present, the atmosphere will become increasingly devoid of carbon dioxide, which is used by plants. This will happen because our planet will receive more heat from the Sun, accelerating rock weathering and increasing the rate of carbon dioxide absorption. Also, the plate tectonics, which recycles nutrients over geological timescales, might end.

We currently produce copious amounts of this gas as a byproduct of industrialization. If our descendants still exist, it’s safe to assume that we will still be supplying the atmosphere with this gas. Hopefully, it will not be ruined by the speed at which we are releasing these gases now.

If the lowering of carbon dioxide concentration can be avoided, the next dangerous step will be the increase in the energy Earth will receive from the aging Sun. If our descendants don’t step up and either build a shade or move Earth’s orbit away, then the upper limit of Earth’s habitability will be around 2 billion years.

It will then become so hot that the oceans will boil away, and we will not be able to live on Earth as it melts under the Sun's expansion. This will happen on timescales of another two billion years or so. Although Earth’s orbit would tend to expand as the Sun loses mass, tidal effects and the Sun’s enormous growth may still lead to engulfment.

At some point, its rocks will melt, and a global magma ocean will cover the surface, erasing the entire history of our planet, the good and the bad. When Sun’s surface approaches really close, Earth will at some point start to be dragged by the Sun’s atmosphere, and it will spiral into its plasma and literally melt. This will only be possible to witness from a distance and not from the surface.

If Hanuman was powerful enough to swallow the sun, why did he need a bridge to cross the ocean?

 

Good question. Hanuma is very powerful but not powerful enough to swallow Sun. There is no need or necessity for Hanuma to swallow Sun.

By seeing Full Moon in night, if we think that we can hold it with our two hands and play like a volleyball, it's not our mistake. From here it looks like that. If we go near, we will come to know its actual size.

From earth, in the morning, Hanuma thought that Sun is a fruit as its size is so small.

Here we should understand an interesting thing. Though we thought of playing with moon, can we or any human fly to moon. Hanuma flew to Sun as a boy. Any doubt about his power?.

Regarding construction of bridge to cross the ocean, it's not for him. It's for the entire army and other warriors.

In fact Hanuma requested Sitamma to sit on his shoulders so that he can fly back with Sitamma to Rama in minutes.

Such is his power.

Jai Hanuman.

Subhamastu

How did the Sun and planets form?

 Here's the story of how the Solar System formed (in fairy tale form, as that seems to be the only thing some people understand).

Once upon a time, a long, long time ago, there was a cloud of dust and other things out in space.

See the center there? That's where the Sun ended up!

Some parts of the cloud were more dense than others. Gravity now took over. The Sun, planets (including Earth), asteroids, and other things formed under this gravity.

But parts of this new Solar System were unstable. Why, Theia even crashed into the Earth!

Part of it became part of the Earth. The rest became our Moon.

But because the Moon was so close, the tides were huge.

Over the billions of years, the Moon settled to where it is now, and the tides settled down.

And that's the story of the origin of the Sun, Moon, and Earth in fairy tale form. Please pay attention to it; after all, it's a picture book!

Sun or Saturn, who is most powerful in a horoscope?

Sun : Lord Surya Narayan is considered king of planets.

Rama : As he is associated with Narayan ; he is adored as Rama, 7th incarnation of Narayan..

Soul : He is also treated as soul of an individual.

Power : His blessings are sought for kingly lifestyle ; vitality and so on.

Father : He happens to be father of entire world.

Well ,he also happens to be father of Yama ; Yamuna ji ; Shanidev ji; Manu ; Ashwin Kumars.

Powerful : Lord Sun becomes the most powerful in 1st or 10th and weakest in 7th house.

Saturn : Lord Shanti Dev is considered judge among planets.

Kali : He is associated with Goddess Kali and also Lord Mahakal.

Judge : He keeps an eye on each individual act -good ; bad or ugly.

Karma : Many astrologers define him as results of our Karma.

Fortune : His blessings and curse can make or break any life.

Son : He happens to be son of Lord Surya Narayan.

Powerful : Saturn becomes auspicious in 10th or 11th house.

Powerless : Shanidev becomes inauspicious in 5th or 8th house.

Remedies : Worship rising Surya Narayan with arghya or Aditya Hrudaya Strota or Rama Nama

Appease Shanidev ji with serving downtrodden ; truthfulness and Shiva Puja and Krishna upasana.

One can appease Surya Narayan and Shani dev by worshipping Lord Hanuman ji, the selfless devotee.

One can also serve cows ; elders ; poor and helpless human beings with selfless service.

Prayer : Sri Ganeshaya Namah Sri Ram Jai Ram Jai Jai Ram Namo Parvatipataye Har Har Mahadev Shambo Jai Jai Jai Hanuman Gosai Kripa Karo Gurudev Ki Nai

Pic Credits : Google Images / Web

Why is the Sun so tiny in comparison to the larger stars discovered?

 There are larger stars - and some MUCH larger stars.

But there are also smaller (and MUCH smaller) stars too.

To the best of our knowledge - our Sun is extremely, boringly AVERAGE.

It’s about halfway through it’s life - it’s kinda halfway into the MilkyWay.

It couldn’t *BE* more normal.

So - sure it’s tiny compared to SOME stars - but it’s pretty big compared to some others.

The smallest known star goes by the catchy name “OGLE-TR-122b” and it’s about the size of Jupiter.

In this diagram - the Sun is on the left…

If you were to be able to touch the sun, would it be hard or soft or would you go through it?

 I think it would be best described with touching a fire. In fact a fire is a plasma, just like the sun.

This analogy covers many aspects of “touching the sun”:

• A fire has no clear boundaries. You might put your arm in it quickly, and the upper arm is more burned than your fingers are. In any case: you never “touch” anything, there is nothing solid or liquid.
• A fire is very hot. Okay, the surface of the sun is much hotter than any ordinary fire. But you get the drift.
• A fire is always in motion. That is again much more extreme for the sun than for a big camp fire. The sun is throwing out jets so big that the planet Jupiter could easily drown in it, if it would get close to the surface. Here’s a picture of such a yet with Earth drawn next to it:

Who or what created our sun?

 It was a little over four and a half billion years ago, in an undisclosed location perhaps a few thousand light years nearer to the center of the Milky Way galaxy than where we find ourselves today.

Great billowing clouds of molecular gas and dust — the supernova remnants of a mega-massive star gone kablooey — swirled and danced in space. This fog was mostly hydrogen and helium; perhaps 2% of the material consisted of heavier elements, a fine dust of iron and carbon and the rest, which had been synthesized through fusion in the exploded star’s core. Metals, in astronomy terms.

A supernova is a messy affair — the distribution was not perfectly even. There were clumps in the vapor. Through the action of gravity, these pockets of density attracted yet more density, more material, into themselves. An object began to form, almost a solid thing. There was angular momentum, rotation; the little upstart anomaly spun and heated as it contracted under its own weight.

Most of the mass gathered into a sphere at the center, where the pressure of so much stuff in such a small space eventually grew great enough to ignite fusion.

Out of the old star, a new generation of star was formed. Meanwhile, the rapid rotation flattened the matter around our protostar into a disc — a protoplanetary disc, so rich and thick with dust that the central furnace was obscured.

These pictures are from Hubble Space Telescope observations of the Orion Nebula, but they are a fairly good approximation of what the birth of our solar system would have looked like. There, against the light background in the center of the second image, is a dark speck, a mere mote, almost completely hiding the infant star burning and churning within.

That is how our Sun and its retinue of planets and asteroids and comets began their existence.

As often as not, these protoplanetary discs host more than one star. Jupiter may have tried and failed to ignite, ultimately acquiescing to a life of tending the planetary herd, leaving the Sun to shine uncontested. Its demotion greatly increased the stability and potential complexity of our system.

Given the chemical signatures we see, it is very likely that our environment coalesced in this way alongside hundreds to thousands of others — a large cluster of star systems formed from the remains of some titanic stellar predecessor.

The Sun and its sibling stars, identities unknown (though there have been suspects), have long since migrated out and away from that primordial stellar tomb turned nursery. We are cosmic orphans; we don’t know who our parent was, or where “the old homeplace” really is. We probably never will.

Our planet’s composition, its geology and tectonics, its atmosphere and biosphere, are all enabled by just a small fraction of the 2% of dust found amid all that etheral gas: life, death, vegetation, the seven seas, grandma’s lasagne, the device in your hand or on your desk right now. All of it began in a clump that first grew, then contracted, spun, ignited, and flattened, against all odds.

Try not to roll your eyes when someone points out that we’re all made of stars. It’s essentially correct.

Is the sun getting hit by asteroids and what would happen if a big one hit it?

The Sun eats asteroids for breakfast.

So you have heard about the asteroid that struck Earth 65 million years ago right? Was that a big one?

All it did was kick up a little dust really. It didn’t move Earth out of it’s orbit or split the planet in two.

So if that one didn’t bother Earth (it only bothered things living on Earth) what would it take to bother the Sun which is considerably larger than us.

Most people don’t grasp the difference in the sizes of various objects in space.

And our sun isn’t a big star.

Now try to imagine the last star in this series beside our?,

That would still not be the same as our sun to a mere speck of an asteroid.