A star is an exploding ball of burning gas held together by gravity. Our sun is a star! It produces great amounts of energy in the form of light and heat that provide the perfect conditions for life on Earth.

Astronomy

Stars are huge, glowing balls of gases. The closest star to Earth is the Sun. Most of the pinpricks of light that shine in the night sky are also stars. Stars are found in huge groups called galaxies. The Sun and its solar system, including Earth, are part of the Milky Way galaxy.

protostar

All stars, irrespective of their size, follow the same 7 stage cycle, they start as a gas cloud and end as a star remnant.

• Giant Gas Cloud. A star originates from a large cloud of gas.
• Protostar.
• T-Tauri Phase.
• Main Sequence.
• Red Giant.
• The Fusion of Heavier Elements.
• Supernovae and Planetary Nebulae.

Eventually the cycle of star birth and death will come to an end. Gravity will have won, a victory delayed by the ability of stars to call on the resources of nuclear fusion. But ultimately, gravity will reduce all stars to a super-dense state as black holes, neutron stars or cold white dwarfs.

Such stars explode when they use up their nuclear fuel and collapse. Stars weighing more than about eight times the Sun’s mass burn through their hydrogen fuel quickly, but as a massive star runs low on one fuel, it taps into another. Each new fuel releases less energy, so the star burns through it even faster.

Molnar and his team determined that the stars would eventually collide, resulting in a kind of stellar explosion known as a “Red Nova”. Initially, they estimated this would take place between 2018 and 2020, but have since placed the date at 2022.

As light from a star races through our atmosphere, it bounces and bumps through the different layers, bending the light before you see it. Since the hot and cold layers of air keep moving, the bending of the light changes too, which causes the star’s appearance to wobble or twinkle.

Some types of stars expire with titanic explosions, called supernovae. When a star like the Sun dies, it casts its outer layers into space, leaving its hot, dense core to cool over the eons. A supernova can shine as brightly as an entire galaxy of billions of “normal” stars.

The path they follow beyond that depends on the mass of the star. Small stars, like the Sun, will undergo a relatively peaceful and beautiful death that sees them pass through a planetary nebula phase to become a white dwarf, which eventually cools down over time and stops glowing to become a so-called “black dwarf”.

The Sun as a red giant will then… go supernova? Actually, no—it doesn’t have enough mass to explode. Instead, it will lose its outer layers and condense into a white dwarf star about the same size as our planet is now. A planetary nebula is the glowing gas around a dying, Sun-like star.

The lack of oxygen to the brain renders you unconscious in less than 15 seconds, eventually killing you. “When the pressure gets very low there is just not enough oxygen. That is really the first and most important concern,” Buckey says. But death is not instantaneous.

The Sun will never turn into a black hole because it is not massive enough to explode. Instead, the Sun will become a dense stellar remnant called a white dwarf.

Even if the Sun somehow converted into a black hole without the initial expansion, explosion and, inevitably, mass loss that normally accompany such transformation, a solar mass black hole will still be tiny! Black holes are about mass squeezed into a point of infinite density, called singularity.

If a black hole were to form from the Earth itself, it would create an event horizon just 1.7 centimeters in diameter. Eventually, some time later, any object at rest — no matter how far away from the event horizon it initially was — will cross that horizon and encounter the central singularity.

HOST PADI BOYD: While they may seem like a hole in the sky because they don’t produce light, a black hole is not empty, It’s actually a lot of matter condensed into a single point. This point is known as a singularity.

Bottom line: simply falling into a black hole won’t give you a view of the entire future of the universe.

It can never leave that region. For all practical purposes the matter has disappeared from the universe. Once inside the black hole’s event horizon, matter will be torn apart into its smallest subatomic components and eventually be squeezed into the singularity.

A stellar-mass black hole forms when a star with more than 20 solar masses exhausts the nuclear fuel in its core and collapses under its own weight. The collapse triggers a supernova explosion that blows off the star’s outer layers.

In principle, a black hole can have any mass equal to or above about 2.21×10−8 kg or 22.1 micrograms (the Planck mass). To make a black hole, one must concentrate mass or energy sufficiently that the escape velocity from the region in which it is concentrated exceeds the speed of light.

For example, a black hole of 1 solar mass takes 1067 years to evaporate (much longer than the current age of the Universe), while a black hole of only 1011 kg will evaporate within 3 billion years.

Black hole evaporation. If black holes evaporate under Hawking radiation, a solar mass black hole will evaporate over 1064 years which is vastly longer than the age of the universe. A supermassive black hole with a mass of 1011 (100 billion) M ☉ will evaporate in around 2×10100 years.

Over time they shrink down to nothing and simply pop away in a flash of energy. It’s not exactly fast. A good size black hole — say, a few times more massive than the sun — will take about 10^100 years to eventually evaporate through this process, known as Hawking Radiation.

A black hole cosmology (also called Schwarzschild cosmology or black hole cosmological model) is a cosmological model in which the observable universe is the interior of a black hole. According to general relativity, the gravitational collapse of a sufficiently compact mass forms a singular Schwarzschild black hole.