Are stars that we see dead?
Every star we can see is almost certainly still alive, dispelling one of astronomy's most popular myths. Mostly Mute Monday tells an astronomical story in images, visuals, and no more than 200 words.
Even though stars are not living things, they have “life cycles” and at some point they are said to “die.” How a star lives and dies depends on how large it is. The smallest stars, brown dwarf stars, are too large to be considered planets, but too small to be considered stars.
But even on average, if we were to consider all 200-400 billion stars in our galaxy, a mean distance of perhaps 40,000 light years away, there are perhaps only a few hundred thousand that are already dead -- one in a million -- and they're heavily skewed towards being on the far side of the galaxy from where we are.
Stars die because they exhaust their nuclear fuel. The events at the end of a star's life depend on its mass. Really massive stars use up their hydrogen fuel quickly, but are hot enough to fuse heavier elements such as helium and carbon.
Stars form from an accumulation of gas and dust, which collapses due to gravity and starts to form stars. The process of star formation takes around a million years from the time the initial gas cloud starts to collapse until the star is created and shines like the Sun.
After a star dies, there is still some residual heat left over. That heat makes the star (white dwarf or neutron star) glow, even though it is not producing any energy. Eventually, the star cools off and does indeed simply become a hunk of ash, which we call a "black dwarf."
Generally, the more massive the star, the faster it burns up its fuel supply, and the shorter its life. The most massive stars can burn out and explode in a supernova after only a few million years of fusion. A star with a mass like the Sun, on the other hand, can continue fusing hydrogen for about 10 billion years.
While most stars quietly fade away, the supergiants destroy themselves in a huge explosion, called a supernova. The death of massive stars can trigger the birth of other stars.
A star is born when atoms of light elements are squeezed under enough pressure for their nuclei to undergo fusion. All stars are the result of a balance of forces: the force of gravity compresses atoms in interstellar gas until the fusion reactions begin.
Birthday: October 17, 1917
At 103, Marsha Hunt is considered the oldest living actor from Hollywood's Golden Age.
How many stars are born a day?
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!
Stars are huge celestial bodies made mostly of hydrogen and helium that produce light and heat from the churning nuclear forges inside their cores. Aside from our sun, the dots of light we see in the sky are all light-years from Earth.
The light travels very fast, so it is unlikely for any of them to have already died while their light was still in transit towards us. Smaller stars live longer than larger stars, and they're the ones still shining in our galaxy.
After the star's outer layer has escaped, the much smaller inner layer collapses into a white dwarf. This star, which is hotter and brighter than the red giant it came from, illuminates and warms the escaped gas, until the gas starts glowing by itself – and we see a planetary nebula.
When a star like the Sun has burned all of its hydrogen fuel, it expands to become a red giant. This may be millions of kilometres across - big enough to swallow the planets Mercury and Venus. After puffing off its outer layers, the star collapses to form a very dense white dwarf.
If there were no stars, all humans would be exposed to cosmic radiation that falls from the atmosphere due to -100 degree temperatures. Without the sun there would be no photosynthesis, causing all plants, animals, and humans to die.
Stars are born within the clouds of dust and scattered throughout most galaxies. A familiar example of such as a dust cloud is the Orion Nebula. Turbulence deep within these clouds gives rise to knots with sufficient mass that the gas and dust can begin to collapse under its own gravitational attraction.
Hipparchus is known for the discovery of the first recorded nova (new star). Many of the constellations and star names in use today derive from Greek astronomy. In spite of the apparent immutability of the heavens, Chinese astronomers were aware that new stars could appear.
A white dwarf is a stellar remnant and can be considered as a dead star in this regard. A "dead" star is one that has no more nuclear fusion going in it. When a star dies, it leaves some remnant behind. Depending on the mass of the star, the remnant can be a white dwarf, neutron star or a black hole.
All of the stars you can see with the unaided eye lie within about 4,000 light-years of us. So, at most, you are seeing stars as they appeared 4,000 years ago.
How old is the Sun?
Stars are mainly made of hydrogen and helium gas. In the centre of a star, the temperature and pressure are so high that four protons can fuse to form helium, in a series of steps. This process releases huge amounts of energy and makes the stars shine brightly.
As stars age, they run out of hydrogen to burn, decreasing the amount of energy they emit. Thus, younger stars can appear bluer while older ones appear more red, and in this way, a star's color can tell us something about that star's age.
The stars are not fixed, but are constantly moving. If you factor out the daily arcing motion of the stars across the sky due to the earth's rotation, you end up with a pattern of stars that seems to never change.
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stars are born in vast clouds of gas and dust. stars spend most of their lives on the main sequence fusing hydrogen gas to helium gas. stars eventually swell up to form a red giant star. stars like the Sun end their lives as planetary nebulae and white dwarfs.
Stars don't burn – two hydrogen atoms fuse to make helium which is a process which releases a lot of energy.
They may contain the mass of one or two Suns but are often just 20 to 40 km in diameter. White dwarf stars are a bit bigger - often similar in size to our planet Earth. The largest supergiant stars can be more than 1500 times larger than our Sun. This makes them over 2,000 million km across.
Namely, every Sun is a star, but not every star is a Sun. The Sun is larger and as such a lot brighter than most stars. There are billions of Suns in our galaxy alone and as mentioned, many of the stars we see are also Suns. But many celestial objects you see when looking up are not stars.
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.
Who is the youngest celebrity alive?
Ryan Kaji, also known as Ryan Guan, is the youngest celebrity globally. Ryan Kaji is a ten-year-old YouTuber from Texas, United States. He is famous for his YouTube channel, called Ryan's World.
| Name | Lifespan | Age |
|---|---|---|
| Helen Burns | 1916–2018 | 101 |
| Bill Butler | 1921– | 101 |
| Anne Buydens | 1919–2021 | 102 |
| John Calvert | 1911–2013 | 102 |
All the stars we see in the night sky are in our own Milky Way Galaxy. Our galaxy is called the Milky Way because it appears as a milky band of light in the sky when you see it in a really dark area. It is very difficult to count the number of stars in the Milky Way from our position inside the galaxy.
While the spatial size of the entire universe is unknown, it is possible to measure the size of the observable universe, which is approximately 93 billion light-years in diameter at the present day.
The UN estimates that around 385,000 babies are born each day around the world (140 million a year). This number will remain relatively stable in the 50 years from 2020 to 2070.
Instead of solids (like rock and soil) and liquids (like water), the Sun is made up mostly of gases and plasma. In fact, the Sun is comprised almost entirely of two extremely hot gases: hydrogen and helium. Stars also usually have trace amounts of heavier elements, such as oxygen, nitrogen, carbon, and iron.
It is, as all stars are, a hot ball of gas made up mostly of Hydrogen.
Johann Bayer was the first to use Greek letters for star names — and four centuries later, we use them still. Here is the constellation Taurus from Bayer's Uranometria atlas of 1603.
Answer: Yes. Since all of the information from objects in the universe travels at the speed of light, and most objects are many light years from us, we are indeed seeing objects as they appeared in the past.
Answer. Kat - No it isn't. It is a big flaming ball of exploding helium or hydrogen, one of the two. Physics not my strong point but no, it is not alive.
Are we made of stardust?
Most of the elements of our bodies were formed in stars over the course of billions of years and multiple star lifetimes. However, it's also possible that some of our hydrogen (which makes up roughly 9.5% of our bodies) and lithium, which our body contains in very tiny trace amounts, originated from the Big Bang.
One Star's End is a Black Hole's Beginning
Most black holes form from the remnants of a large star that dies in a supernova explosion. (Smaller stars become dense neutron stars, which are not massive enough to trap light.)
Eventually, the fuel of the sun - hydrogen - will run out. When this happens, the sun will begin to die. But don't worry, this should not happen for about 5 billion years. After the hydrogen runs out, there will be a period of 2-3 billion years whereby the sun will go through the phases of star death.
Stars like our Sun burn for about nine or 10 billion years. 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.
A "falling star" or a "shooting star" has nothing at all to do with a star! These amazing streaks of light you can sometimes see in the night sky are caused by tiny bits of dust and rock called meteoroids falling into the Earth's atmosphere and burning up.
Answer 3: Very large stars explode when they run out of fuel. Stars burn hydrogen (H) in their core throughout their lifetime. We call it "burning", but what is really happening is that H atoms are crashing together to form helium (He) atoms.
A "dead" star is one that has no more nuclear fusion going in it. When a star dies, it leaves some remnant behind. Depending on the mass of the star, the remnant can be a white dwarf, neutron star or a black hole. White dwarfs are what was once the core of a star.
All of the stars you can see with the unaided eye lie within about 4,000 light-years of us. So, at most, you are seeing stars as they appeared 4,000 years ago.
These stars are most probably around 15 billion years old, but they could conceivably be as young as 12 billion years or as old as 18 billion years.
All the stars we see in the night sky are in our own Milky Way Galaxy. Our galaxy is called the Milky Way because it appears as a milky band of light in the sky when you see it in a really dark area. It is very difficult to count the number of stars in the Milky Way from our position inside the galaxy.
How do dead stars look?
The waves look like ripples in a pond. The heart is the crushed core of the exploded star, or supernova. Called a neutron star, it has about the same mass as the sun but is squeezed into an ultra-dense sphere that is only a few miles across and 100 billion times stronger than steel.
This was certainly the case for the planets and moons of our Solar System, which formed around 4.6 billion years ago out of the disc of gas and dust spinning around our newborn Sun. But now, a new study published in Astronomy & Astrophysics has found that dying stars can give birth to planets, too.
When a star like the Sun has burned all of its hydrogen fuel, it expands to become a red giant. This may be millions of kilometres across - big enough to swallow the planets Mercury and Venus. After puffing off its outer layers, the star collapses to form a very dense white dwarf.
A star is born when atoms of light elements are squeezed under enough pressure for their nuclei to undergo fusion. All stars are the result of a balance of forces: the force of gravity compresses atoms in interstellar gas until the fusion reactions begin.
Stars are huge celestial bodies made mostly of hydrogen and helium that produce light and heat from the churning nuclear forges inside their cores. Aside from our sun, the dots of light we see in the sky are all light-years from Earth.
The stars are not fixed, but are constantly moving. If you factor out the daily arcing motion of the stars across the sky due to the earth's rotation, you end up with a pattern of stars that seems to never change.
No, the universe contains all solar systems, and galaxies. Our Sun is just one star among the hundreds of billions of stars in our Milky Way Galaxy, and the universe is made up of all the galaxies – billions of them.
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.
Johann Bayer was the first to use Greek letters for star names — and four centuries later, we use them still. Here is the constellation Taurus from Bayer's Uranometria atlas of 1603.
Astronomy > The Milky Way Galaxy. Did you know that our star, the Sun, is just one of hundreds of billions of stars swirling within an enormous cosmic place called the Milky Way Galaxy? The Milky Way is a huge collection of stars, dust and gas.
How big is a star?
They may contain the mass of one or two Suns but are often just 20 to 40 km in diameter. White dwarf stars are a bit bigger - often similar in size to our planet Earth. The largest supergiant stars can be more than 1500 times larger than our Sun. This makes them over 2,000 million km across.
Namely, every Sun is a star, but not every star is a Sun. The Sun is larger and as such a lot brighter than most stars. There are billions of Suns in our galaxy alone and as mentioned, many of the stars we see are also Suns. But many celestial objects you see when looking up are not stars.