black
esiegel | February 6, 2013"According to the special theory of relativity nothing can travel faster than light, so that if light cannot escape, nothing else can either. The result would be a black hole: a region of space-time from which it is not possible to escape to infinity." -Stephen Hawking
You may have encountered objects that are the same size as one another, but have very different masses.
Image credit: Basic Science Supplies / © Accelerate Media.
This is because they're made out of different elements. The higher you go in the periodic table, the larger and more massive your individual atoms are, and so…
sastyk | July 27, 2011And in non-goat news....
According to the study, the inflation-adjusted median wealth among Hispanic households fell 66% from 2005 to 2009. Black households suffered a 53% drop in net worth over the same period. By contrast, whites saw a decline of 16% in household wealth.
In 2009, the typical black household had just $5,677 in wealth. Hispanic families had about $6,325 in wealth. The average white household had a net worth of $113,149.
The study also showed that a third of black and Hispanic households had zero wealth, meaning that their debts were larger than the value of all their assets.…
stoat | July 15, 2011Further proof of the polarisation in this "debate" comes from Climate: Cherries are not the only fruit by Richard Black. This all stems from Reconciling anthropogenic climate change with observed temperature 1998-2008 by Robert K. Kaufmann et al., who come to the not-desperately-exciting conclusion that things are pretty much as we thought they were: recent global temperature records are consistent with the existing understanding of the relationship among global surface temperature, internal variability, and radiative forcing, which includes anthropogenic factors with well known warming and…
edyong | November 23, 2009In the early days of the last US elections, Hillary Clinton's campaign was accused of deliberately darkening Barack Obama's skin in a TV ad. The implication was that by highlighting Obama's "blackness", Clinton's camp was trying to exploit negative associations that voters might have with darker skin. But you don't need editing software to do that - a fascinating new study suggest that people literally change the way they see a mixed-race politician, depending on whether the candidate represents their own political views.
Liberal American students tend to think that lighter photos of Barack…
rallain | July 8, 2009What do you see when you are in a completely dark room with no lights?
That is a great question to ask. It can bring out some interesting ideas. Anyway, here is an easy demo to show the color black. The basic idea is to build a box that has a small opening. Here is what it looks like from the outside:
As you can see, just a basic box. I have a door on the top, and I put a paper towel tube for a window. To make it look pretty, I covered it with black paper (so you couldn't tell where I stole the box from).
To demo this to students, I first go around and let everyone look inside. I ask…
edyong | April 16, 2009In American high schools, black students typically perform worse than their white peers, which can damage their self-esteem and their future prospects. Studies have found that the fear of living up to this underachieving stereotype can cause so much stress that a child's performance suffers. Their teachers may even write them off as lost causes, and spend less time on them.
With so many students caught in this vicious cycle, where the stereotype of poor performance strengthens itself, it might seem absurd to suggest that you could turn things round in less than an hour. But try telling that…
esiegel | May 16, 2008This has been all over my inbox since the press release came out yesterday; it's been on slashdot (thanks Brian), it's been at space.com, and there's a mediocre writeup on Universe Today. What's the big news? Black Holes don't destroy information after all!
What is this whole information thing, anyway? Take a look at all the normal stuff in the Universe: photons, protons, neutrons, and electrons, for example. They have lots of different properties each. They move around one another, they get bound and unbound from one another, they exert forces on one another, etc. They're aware of one…
esiegel | April 29, 2008No, not because it was too young to drink! Scientists at the Max Planck Institute for Extraterrestrial Physics were looking at some X-ray objects, and discovered something really weird: a very bright X-ray source moving out of a galaxy at nearly 3,000 kilometers/second! This thing is a goner. If our Sun were moving at even one quarter of that speed, it would get thrown out of our galaxy.
Now, here's the kicker: this isn't just any old object getting tossed out of a galaxy, it is a huge black hole! How huge? About 300,000,000 times the mass of our Sun. You read that number right: 300,000,000…