So if you've ever wondered what it might look like to fall into a Black Hole, wonder no longer! From an article at New Scientist, researchers at the University of Colorado - Boulder
built a computer code based on the equations of Einstein's general theory of relativity, which describes gravity as a distortion of space and time.
They follow the fate of an imaginary observer on an orbit that swoops down into a giant black hole weighing 5 million times the mass of the sun, about the same size as the hole in the centre of our galaxy.
[Note: There are more details on what exactly is happening in the video in the article linked above.]
Thanks to Mr. Jue over at the fledgling STEMpowerment blog for the article.
This is a really nifty video that explains how the Financial Crisis happened (and is still happening) in the US. It's got all the info you need to understand what's happening in the news -- just don't get intimidated by the big words (all of them get explained eventually).
The video above is about 11 minutes long and explains what happened in broad terms. It give the essential background of the Crisis.
On the other hand, if you would like a detailed account of the specific decisions made and actions taken by both the Wall Street banks and the US Government as the crisis unfolded over the Summer and Fall of last year (to try to stop the banks from failing), then check out this (hour long) video. It's an episode of Frontline, called (menacingly) "Inside the Meltdown."
Also, I've been posting links to the episodes of the radio show This American Life that similarly explain the Financial Crisis in ways that people can actually understand. Well, they just aired a new one about what the US Government is trying to do right now to save our sinking economy (and why it's so hard to figure out what to do). It's called, Bad Bank.
In the same spirit as the post a while back on Khan Academy, I've found a new general resource for learning via the Internet. It's called Academic Earth.
Essentially, Academic Earth is a collection of lectures from college classes, but some of them can be pretty relevant for high schoolers, or at least they can be entertaining.
"And this really gave me the creeps cause it was as if this inanimate thing, this pendulum knew algebra. How could this thing swinging back and forth know something about parabolas, or how could that be built in? And so, it was in that moment that I understood what people mean when they say 'There is a Law of Nature'."
My attention was recently directed to a website called the Khan Academy. It's a huge library of YouTube video-lessons on Math and Science, and I've got a feeling that they're going to change the way that I do things on this blog.
Check them out, if there's something Math-related that you're wondering about, this guy probably has a lesson on it.
In 1969, when humans first landed on the moon (on the Apollo 11 mission), one of the first things they did was drop a feather and a hammer to test which would hit the ground first. Why do you think they were interested?
What happens when you drop a hammer and a feather (at the same time, from the same height) here on Earth?
Is there any difference between performing the experiment on Earth and on the Moon?
Pre-Galileo Did you hear the name that the astronaut mentioned? It was Galileo Galilei's. (Galileo was a physicist-astronomer who lived in Italy from 1564-1642.) For thousands of years before him, people believed that Gravity was a mysterious force that made things fall toward the Earth -- and they believed that the heavier the object, the faster it would fall. But Galileo changed everything.
Before we look at Galileo's theory, let's consider where the "old" belief about gravity came from. When you drop a hammer and a feather at the same time (here on Earth), the hammer will always land first. And if you try the experiment with all different kinds of things, this is pretty much always going to be the case for a heavy object and a lighter one: The heavier object tends to fall faster. Scientists observed this phenomenon for thousands of years and came to the conclusion that gravity affected heavier objects more than lighter ones.
However, they were not conducting their experiments on the Moon.
Galileo Galileo (without ever leaving the Earth) did experiments many different objects that fell from many heights and rolled balls with different weights down inclined planes. Eventually, he came to the conclusion that gravity accelerates all objects at the same rate, regardless of their weight.
That means that even here on Earth, a hammer and a feather should land at the same time (like on the Moon). So why don't they? The answer: Air.
You know how when you ride a bike, you feel a breeze on your face (even when there's no wind that day)? The air is standing still, but you are moving, so it ends up feeling like there is wind pushing against the direction you're trying to go. It's the same principle with the hammer and the feather. A light breeze isn't going to push a hammer around, but it'll carry a feather away easily.
In the case of a hammer/feather drop, the breeze is trying to push each object in the opposite direction of the way they are falling (like the "wind" pushes against the direction you are trying to ride your bike). So even though Gravity is trying to accelerate both the hammer and feather at the same rate toward the Earth, the "wind" is blowing them in the other direction. On the Moon though, there's no air, so the hammer and feather can freely accelerate.
Partly to put my Math lessons in a public forum. Partly to expose readers to diverse subject matter (and for me to post links to cool stuff that I wouldn't want to forget).
