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Interesting facts about stars
Stars are giant, luminous spheres of plasma. There are billions of them — including our own sun — in the Milky Way Galaxy. And there are billions of galaxies in the universe. So far, we have learned that hundreds also have planets orbiting them.
1. Stars are made of the same stuff
All stars begin from clouds of cold molecular hydrogen that gravitationally collapse. As they cloud collapses, it fragments into many pieces that will go on to form individual stars. The material collects into a ball that continues to collapse under its own gravity until it can ignite nuclear fusion at its core. This initial gas was formed during the Big Bang, and is always about 74% hydrogen and 25% helium. Over time, stars convert some of their hydrogen into helium. That’s why our Sun’s ratio is more like 70% hydrogen and 29% helium. But all stars start out with ¾ hydrogen and ¼ helium, with other trace elements.
2. Most stars are red dwarfs
If you could collect all the stars together and put them in piles, the biggest pile, by far, would be the red dwarfs. These are stars with less than 50% the mass of the Sun. Red dwarfs can even be as small as 7.5% the mass of the Sun. Below that point, the star doesn’t have the gravitational pressure to raise the temperature inside its core to begin nuclear fusion. Those are called brown dwarfs, or failed stars. Red dwarfs burn with less than 1/10,000th the energy of the Sun, and can sip away at their fuel for 10 trillion years before running out of hydrogen.
3. Mass = temperature = color
The color of stars can range from red to white to blue. Red is the coolest color; that’s a star with less than 3,500 Kelvin. Stars like our Sun are yellowish white and average around 6,000 Kelvin. The hottest stars are blue, which corresponds to surface temperatures above 12,000 Kelvin. So the temperature and color of a star are connected. Mass defines the temperature of a star. The more mass you have, the larger the star’s core is going to be, and the more nuclear fusion can be done at its core. This means that more energy reaches the surface of the star and increases its temperature. There’s a tricky exception to this: red giants. A typical red giant star can have the mass of our Sun, and would have been a white star all of its life. But as it nears the end of its life it increases in luminosity by a factor of 1000, and so it seems abnormally bright. But a blue giant star is just big, massive and hot.
4. Most stars come in multiples
It might look like all the stars are out there, all by themselves, but many come in pairs. These are binary stars, where two stars orbit a common center of gravity. And there are other systems out there with 3, 4 and even more stars. Just think of the beautiful sunrises you’d experience waking up on a world with 4 stars around it.
5. The biggest stars would engulf Saturn
Speaking of red giants, or in this case, red supergiants, there are some monster stars out there that really make our Sun look small. A familiar red supergiant is the star Betelgeuse in the constellation Orion. It has about 20 times the mass of the Sun, but it’s 1,000 times larger. But that’s nothing. The largest known star is the monster UY Scuti. It is a current and leading candidate for being the largest known star by radius and is also one of the most luminous of its kind. It has an estimated radius of 1,708 solar radii (1.188×109 kilometres; 7.94 astronomical units); thus a volume nearly 5 billion times that of the Sun.
6. There are many, many stars
Quick, how many stars are there in the Milky Way. You might be surprised to know that there are 200-400 billion stars in our galaxy. Each one is a separate island in space, perhaps with planets, and some may even have life.
7. The Sun is the closest star
Okay, this one you should know, but it’s pretty amazing to think that our own Sun, located a mere 150 million km away is average example of all the stars in the Universe. Our own Sun is classified as a G2 yellow dwarf star in the main sequence phase of its life. The Sun has been happily converting hydrogen into helium at its core for 4.5 billion years, and will likely continue doing so for another 7+ billion years. When the Sun runs out of fuel, it will become a red giant, bloating up many times its current size. As it expands, the Sun will consume Mercury, Venus and probably even Earth.
8. The biggest stars die early
Small stars like red dwarfs can live for trillions of years. But hypergiant stars, die early, because they burn their fuel quickly and become supernovae. On average, they live only a few tens of millions of years or less.
9. Failed stars
Brown dwarfs are substellar objects that occupy the mass range between the heaviest gas giant planets and the lightest stars, of approximately 13 to 75–80 Jupiter masses (MJ). Below this range are the sub-brown dwarfs, and above it are the lightest red dwarfs (M9 V). Unlike the stars in the main-sequence, brown dwarfs are not massive enough to sustain nuclear fusion of ordinary hydrogen (1H) to helium in their cores.
10. Sirius: The Brightest Star in the Night Sky
Sirius is a star system and the brightest star in the Earth’s night sky. With a visual apparent magnitude of −1.46, it is almost twice as bright as Canopus, the next brightest star. The system has the Bayer designation Alpha Canis Majoris (α CMa). What the naked eye perceives as a single star is a binary star system, consisting of a white main-sequence star of spectral type A0 or A1, termed Sirius A, and a faint white dwarf companion of spectral type DA2, called Sirius B.
To know more click the links: white dwarf, supernova, +stars, pulsars
sources: wikipedia and universetoday.com
image credits: NASA/JPL, Morgan Keenan, ESO, Philip Park / CC BY-SA 3.0
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1. There are plenty of ways to enter a pool. The stairs is not one of them. 2. Never cancel dinner plans by text message. 3. Don’t knock it ‘til you try it. 4. If a street performer makes you stop walking, you owe him a buck. 5. Always use ‘we’ when referring to your home team or your government. 6. When entrusted with a secret, keep it. 7. Don’t underestimate free throws in a game of ‘horse’. 8. Just because you can doesn’t mean you should. 9. Don’t dumb it down. 10. You only get one chance to notice a new haircut. 11. If you’re staying more than one night, unpack. 12. Never park in front of a bar. 13. Expect the seat in front of you to recline. Prepare accordingly. 14. Keep a picture of your first fish, first car, and first boy/girlfriend. 15. Hold your heroes to a high standard. 16. A suntan is earned, not bought. 17. Never lie to your doctor. 18. All guns are loaded. 19. Don’t mention sunburns. Believe me, they know. 20. The best way to show thanks is to wear it. Even if it’s only once. 21. Take a vacation of your cell phone, internet, and TV once a year. 22. Don’t fill up on bread, no matter how good. 23. A handshake beats an autograph. 24. Don’t linger in the doorway. In or out. 25. If you choose to go in drag, don’t sell yourself short. 26. If you want to know what makes you unique, sit for a caricature. 27. Never get your hair cut the day of a special event. 28. Be mindful of what comes between you and the Earth. Always buy good shoes, tires, and sheets. 29. Never eat lunch at your desk if you can avoid it. 30. When you’re with new friends, don’t just talk about old friends. 31. Eat lunch with the new kids. 32. When traveling, keep your wits about you. 33. It’s never too late for an apology. 34. Don’t pose with booze. 35. If you have the right of way, take it. 36. You don’t get to choose your own nickname. 37. When you marry someone, remember you marry their entire family. 38. Never push someone off a dock. 39. Under no circumstances should you ask a woman if she’s pregnant. 40. It’s not enough to be proud of your ancestry; live up to it. 41. Don’t make a scene. 42. When giving a thank you speech, short and sweet is best. 43. Know when to ignore the camera. 44. Never gloat. 45. Invest in good luggage. 46. Make time for your mom on your birthday. It’s her special day, too. 47. When opening presents, no one likes a good guesser. 48. Sympathy is a crutch, never fake a limp. 49. Give credit. Take blame. 50. Suck it up every now and again. 51. Never be the last one in the pool. 52. Don’t stare. 53. Address everyone that carries a firearm professionally. 54. Stand up to bullies. You’ll only have to do it once. 55. If you’ve made your point, stop talking. 56. Admit it when you’re wrong. 57. If you offer to help don’t quit until the job is done. 58. Look people in the eye when you thank them. 59. Thank the bus driver. 60. Never answer the phone at the dinner table. 61. Forgive yourself for your mistakes. 62. Know at least one good joke. 63. Don’t boo. Even the ref is somebody’s son. 64. Know how to cook one good meal. 65. Learn to drive a stick shift. 66. Be cool to younger kids. Reputations are built over a lifetime. 67. It’s okay to go to the movies by yourself. 68. Dance with your mother/father. 69. Don’t lose your cool. Especially at work. 70. Always thank the host. 71. If you don’t understand, ask before it’s too late. 72. Know the size of your boy/girlfriend’s clothes. 73. There is nothing wrong with a plain t-shirt. 74. Be a good listener. Don’t just wait for your turn to talk. 75. Keep your word. 76. In college, always sit in the front. You’ll stand out immediately. 77. Carry your mother’s bags. She carried you for nine months. 78. Be patient with airport security. They’re just doing their jobs. 79. Don’t be the talker in a movie. 80. The opposite sex likes people who shower. 81. You are what you do, not what you say. 82. Learn to change a tire. 83. Be kind. Everyone has a hard fight ahead of them. 84. An hour with grandparents is time well spent. Ask for advice when you need it. 85. Don’t litter. 86. If you have a sister, get to know her boyfriend. Your opinion is important. 87. You won’t always be the strongest or the fastest. But you can be the toughest. 88. Never call someone before 9am or after 9pm. 89. Buy the orange properties in Monopoly. 90. Make the little things count. 91. Always wear a bra at work. 92. There is a fine line between looking sultry and slutty. Find it. 93. You’re never too old to need your mom. 94. Ladies, if you make the decision to wear heels on the first date, commit to keeping them on and keeping your trap shut about how much your feet kill. 95. Know the words to your national anthem. 96. Your dance moves might not be the best, but I promise making a fool of yourself is more fun than sitting on the bench alone. 97. Smile at strangers. 98. Make goals. 99. Being old is not dictated by your bedtime. 100. If you have to fight, punch first and punch hard.
a high school teacher’s list of 100 wisest words (via live-la-bella-e-vita)
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The rabies virus causes a fear of water. Rabies victims experience difficulty swallowing and muscle spasms in the throat when they try to swallow. Hence, since you need to swallow in order to drink water, these people begin to fear water, as the sight of it causes even more painful spasms. The fear of water these people experience is more technically known as hydrophobia, where ‘hydro’ means water and 'phobia’ means fear. (Source)
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This is what it would be like to travel through Jupiter if it was possible. It was written by reddit user wazoheat.
Well, if you weren’t wearing a space suit, no matter where you started you would die almost instantly because there is essentially no oxygen at any level of Jupiter’s atmosphere. But let’s say you do have a space suit. What do you mean by “step foot on it”? Jupiter is, as you noted in your question, a gas giant, meaning it’s made of gas. There is no solid surface. And just like Earth’s atmosphere, the gas doesn’t really have a “top”, it just gets thinner and thinner as you get further and further from the planet, until at some point it is indistinguishable from interplanetary space (which, you may be interested to know, is not a true vacuum. But let’s say you just get dropped from some height way outside of Jupiter’s visible atmosphere.
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things english speakers know, but don’t know we know.
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Bravely plunging into the unknown, Herrle decided to build the house of his dreams, hoping to lead a more Waldenesque self-sufficient life of simplicity. Best of all, his beloved fiancée also was of the same mind, so Herrle set about building their future home, keeping the footprint small but functional, and using salvaged materials whenever he could.
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at what point in history do you think americans stopped having british accents
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wtf….I can’t even walk without tripping how she do that……
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