TedEd: Why can’t we see evidence of alien life?

A TedEd by Chris Anderson

There must be planets with life in our vast universe, right? So, why can’t we see them. This was explored by Enrico Fermi 1950. The Kepler space observatory has found hundreds of planets nearby in just the last year. If we multiply the data, that means there could be half a trillion planets in just our galaxy. If just one in 10,000 supports life, that’s 50 million potentially inhabited planets. So where are they? Our planet formed 9 billion years after the Big Bang, which means many other planets should have formed before ours and allowed life a chance. If a few of them had grown into intelligent civilizations, they would have had millions of years to advance technologically. We’ve seen time and time again on Earth that progress can take as little as 100 years. This means that any intelligent life form would have spread out, created interstellar spaceships, or at least emitted some sign of their presence through electromagnetic waves. There are many theories as to why we can’t see this. First, one super-intelligent species could have taken over the universe and imposed radio silence to blot out any potential competitors. Or perhaps intelligent life is far rarer than we think, and we are truly alone. Or, perhaps advanced life can’t control its own technological advances and obliterates itself. But there are more hopeful answers. First, we are spending very little on the search, and not looking very hard. Very few stars have truly been searched for interesting signals. We could be looking at the wrong signal, too. Intelligent life could have discovered a way to transmit through dark matter, which accounts for most of the universe’s mass. Or, aliens might have converted to life on a microscopic scale because life is better that way. There are also many experiments on Earth trying to create life from scratch. Either way, the search for life continues. Who knows? Maybe we are all alone.

TedEd: A brief history of chess

A TedEd by Alex Gendler

Chess has been many thinks throughout is millennia of existence. Our earliest records of it are from the 7th century, but a legend points toward its beginnings in the 6th century. When a Gupta prince was killed in battle, his brother came up with a way to represent this to their mother. It was set on an 8x8 ash tapada board, and it was known as Chaturanga - Sanskrit for “four divisions”. Its key features were different movement rules for different pieces, and a king whose fate decided the game. In Persia, it acquire its current name - chess from “shah”, meaning king, and checkmate from “shah mat”, the king is helpless. It spread to Arabia after its conquest of Persia in the 7th century, becoming a source of poetic imagery. The Silk Road took the game to Asia, resulting in many variants. In China, the pieces were placed at corners of square as in Go, and in Japan, captured pieces could be used by the opponent. In Europe, it took its modern form. It became a part of court society, being used as a metaphor for people performing their proper social roles. For this reason, it was disliked by the Church. In the 15th century, the piece of advisor became the powerful queen, becoming the game we know today. The game began to be analyzed, creating Chess Theory, and moved to the public. Up to the 19th century, when formal competition began, dramatic play was popular. It took on a more important role in geopolitical power, with the USSR cultivating the best chess talent, and causing Russia to dominate the championships for a century. However, newly emerging tech has ousted humans altogether, starting with the IBM computer Deep Blue. It is good to remember, however, that these breakthroughs have been the result of human ingenuity.

TedEd: Why do people fear the wrong things?

A TedEd by Gerd Gigerenzer

Risk can be represented in two ways: absolute and relative. Relative risk is comparing risk to the previous risk, while absolute percentages are represented in the current overall percentage. Let's say there is a new drug that can reduce heart attacks. Out of 1000 people in a control group, 10 get a heart attack. In a group that gets the drug, only 6 do. That means there is a relative risk reduction of 40%, while the absolute risk goes from 1% to 0.6% - not a big change. The relative risk reduction makes the drug seem more substantial. But let's say it caused cancer in 0.5% of the patients. In our group of 1000, there would be 4 less heart attacks, but 5 more cases of cancer. Even though the relative percentage of 40% sounds much bigger than the absolute cancer risk of 0.5%, they end up in about the same number. However, risk evaluation varies for everyone. If you know that you have a genetically high risk of heart attack, you might take the drug despite the chance of getting cancer. There are also many cases with no correct answer. Some may skip a swim in the ocean because of the tiny probability of a shark attack, while others wouldn't dream of such a thing. But understanding how measures of risk work is a good step toward making sure you do it right.

The Fault In Our Stars

The Fault In Our Stars

By John Green

Read in 9th Grade

Hazel Grace Lancaster is a 16-year-old girl with lung cancer. She attends a support group for cancer kids, but only because she wants to appease her mother. Hazel generally considers it a waste of time - until she meets Augustus Waters. He once had cancer in his leg, which had to be amputated. Now, he is at the support group with his soon to be blind friend, Isaac, who has eye cancer. Hazel looks remarkably like his dead girlfriend, Caroline Mathers. He immediately asks her out, and by the end of the night, they have exchanged books. Her favorite book is An Imperial Affliction by Peter Van Houten, narrated by a girl named Anna, who has cancer.