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Black Holes 101

Black Holes aren’t just made-up stuff in sci-fi movies – they may actually exist! So what exactly are they – and what are the chances of you ever coming across one in your lifetime?


A Star is Born

Stars are born every day. Just like people, these balls of hot gas grow up, get older and eventually die. Unlike people, stars shrink as they age. Inside a huge young star, hydrogen atoms crash into each other to form helium in a process called nuclear fusion, which releases huge amounts of energy. We see some of that energy as light. If we’re close enough to the star, we can also feel that energy as heat.


Battle Zone

A star is basically a battle zone its whole life. Not only does its own gravitational force attract anything nearby, it also pulls the star itself inward, trying to crush it into a super-dense, super-small mass. At the same time, the star’s nuclear engine gives off a huge amount of energy that pushes outward, counteracting the inward force of the star’s own gravity. As a result, the star doesn’t explode or collapse.


However, when a star starts to run out of hydrogen, there’s a lot less energy being given off to counteract the gravitational force that’s pulling inward. Eventually, the star collapses. The bigger the star, the smaller the mass it collapses to become when it dies.


Ashes, Ashes

When a mid-size star like our own sun dies, its gravitational force turns it into a heap of ash about the size of the Earth. Considering you could fit a million Earths into the sun, that’s a pretty small, extremely dense mass of stuff. But that’s nothing compared to what happens when a truly massive star collapses – the pressure is so huge that the star’s electrons actually get shoved into the nuclei of its atoms, where they react with the protons to form neutrons. The star, now made mostly of jammed-together neutrons, is called a Neutron Star, and it’s squeezed together so tightly that a golfball-sized piece of it would actually weigh as much as a billion elephants!


The Death of a Star: The Inside Story

When the biggest stars collapse, their gravitational pull becomes so huge that NOTHING can escape their pull – not even light. This makes them INVISIBLE, which is why they are called Black Holes. Anything and everything that comes near a black hole – gas, light, astronauts – gets sucked in, never to be seen again. A black hole is definitely not a good spot for a vacation!


If you’re confused about how light can be “sucked in” by gravity, think of it this way: On Earth, you can beat the pull of gravity if you travel fast enough – about 7 miles per second. This is how fast a spaceship must go in order to be launched. A black hole has such tremendous gravitational pull that in order to escape it you must travel at more than the speed of light, which is 186,000 miles per second. Nothing can go faster than light – not even light (of course!). That’s why a black hole is black. So how do we know it’s there?


Back in Black

In 1970, the satellite Uhuru came across a star called Cygnus 1 that was acting mighty strange, as though it were being dragged around by something that couldn’t be seen. This invisible something had the gravitational pull of 10 suns and appeared to be tearing gas away from the star. Yet, despite gobbling up all that bright, glowing gas, it did not glow. That was the first good piece of evidence for a black hole. Since then, lots more evidence has been collected by the Hubble Space Telescope.


Some astronomers think all this evidence that’s been collected means there are super-massive black holes made from millions of collapsed stars at the center of every galaxy. There may also be mini black holes the size of pencil points or peas! And some people even believe black holes are gateways to other universes. If that’s a door you think you may like to walk through, just be sure you’ve got a round-trip ticket!


Video: Black Holes


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-Gwen9--
-Gwen9-- posted in New Users:
I commented Jordan about it. I found it a great idea. 
reply 9 minutes
Black_Rose_19
Black_Rose_19 posted in Debating:
Haha, I guess after looking at your facts, you win. I still am pretty bad at this, so I'm quick to give up, but you've actually successfully changed my opinion on this, so props to you. Well, that's what I get for messing with the master.
reply 10 minutes
naruto200
naruto200 posted in New Users:
Yeah, i'm not blaming you for that. Just, they might find it annoying. But kw should make a tutorial video for kw though. That would be so appreciated by new users.
reply 19 minutes
-Gwen9--
-Gwen9-- posted in New Users:
I don't mean for it to be spread out into posts, but there is a character limit. 
reply 26 minutes
AlphaT
AlphaT posted in Debating:
"Black_Rose_19" wrote:I originally got this story from a source that most people wouldn't exactly call credible , a comedy/politics TV show, but after checking their sources, I believe I have a strong case with decently strong sources.  I hope so. I'm using the same source that John used for debate's sake.  "Black_Rose_19" wrote:You are incorrect when you said you'd only have to pay for labor and materials, as several other factors come into play. Factors...such as? "Black_Rose_19" wrote: Also, where I said 1000 feet, I very much apologize, more like 1000 miles. It should cost about 10 billion for the concrete panels, and although concrete is cheap, it's not dirt cheap, and 1000 miles of concrete will add up to a pretty good amount.  It's okay, I adjusted ## ####### to miles, but somehow still said feet. The same estimate I gave is found in the article, which is around eight million cubic yards of concrete. This would total out to roughly thirty two billion pounds of concrete, which totals out to 533 million bags of concrete, each weighing sixty pounds. The average cost of a sixty pound bag of concrete is $2.83, which we them multiply by 533 million to get 1.5 billion.  This is where I messed up. I used the standard price of unmixed concrete, when I needed to use the standard price of precast slabs. Oliver's source does the rest:  "A cement manufacturer said prices are now running $85 to $90 a cubic yard, so that works out to about $700 million just for the concrete" However, in an update, they nixed the math all together and went with an anonymous economist's unevidenced estimate:  "He worked through some of the math, though he did not want to be identified publicly. Roughly, he said a wall of this type would cost at least $25 billion" This is what John Oliver used on his show. As the unknown economist cites no reason for us to think that the cost would be anywhere near his estimate, I see no reason to think his estimate is valid.  So, effectively, we've reduced the cost from 3 billion to 700 million. Let's the keep the billion dollar safe fund though. Total so far: 1.7 Billion "Black_Rose_19" wrote:Next it should cost 5-6 billion dollars for steel columns to hold the panels, including labor. Really? Including labor? Fine with me. I'm honestly not sure how much steel would be needed for each panel, so I'll defer to this estimate.  Total Cost so far: 6.7 Billion "Black_Rose_19" wrote:Add another billion for concrete footing and foundations, and that's sixteen billion dollars. The Washington Post article included foundation in their total assessment of the concrete required. "Black_Rose_19" wrote:But, transport is required to inaccessible areas. It will cost about another 2 billion dollars to build roads that will allow 20 ton trucks to carry materials to the wall. At ten million dollars per mile, a road spanning the entire length of the wall would require ten billion dollars. Why do you think a fifth of this cost would be required?  The average cost of a road which would allow such transport is 5 million per mile. Let's overestimate the length that would be required to two hundred miles. That gets you to 1 billion.  Total cost so far: 7.7 Billion "Black_Rose_19" wrote:We also need engineering, design, and management, which brings us up to the magic number of 25 billion dollars, on average considering all factors. The Congressional Budget office also says that wall management costs will exceed the original cost to build the wall in as little as seven years. From your previous estimate of eighteen billion, I'll assume that you're factoring in seven billion dollars worth of engineering, design, and management? Why do you think it'll cost that much? To pay every engineer, designer, and manager who would ever work on the wall...I'd put aside about 1.5 billion. Total cost: 9.2 Billion Well what do you know. About a sixth of the annual trade deficit with Mexico, and almost a third of your original estimate.  "Black_Rose_19" wrote:With the Mexico paying for it part, as John Oliver, the host of this show, says, "People don't exactly love it when you make them pay for [expletive] they don't want." The current Mexican treasury secretary states, "Mexico, under no circumstance, is going to pay for the wall that Mr. Trump is proposing." 2 former Mexican presidents that only recently left office also say, in a nutshell, that Mexico will never pay for the wall.  They won't love it, but they will pay for it. If they refuse, Trump plans to put a 35% tariff on all Mexican import. In other words, every company in Mexico will have to pay 35% the value of whatever they're bringing into The United States. Mexico will lose more money paying this tariff than they would by financing the wall, so either way the United States gets the money it needs to build the wall from Mexico. 
reply 39 minutes