The Most Astounding Fact

Neil DeGrasse Tyson was asked by a reader of TIME magazine, "What is the most astounding fact you can share with us about the Universe?" This is his video response, an incredible and humbling take on the universe:

Under the Microscope

 

The human body is an amazing instrument with the ability to heal itself from a variety of different maladies. A T cell (depicted in the video above) is one of the immune system's responses to external threats. These cells identify and attack diseased cells in order to eradicate them from the host's body. A cytotoxic T cell, which is what the above cell is classified as, exists with the single purpose of going around looking for cancerous cells, whereupon is eradicates them without causing any damage to the healthy cells in the area.

The Vastness of the Universe

How big is the Universe? Well, what do you want to compare it to? After all, it's all relative. It's interesting to note that between the Planck length and the size of the known universe, humans (magnitude 10⁰⁾ are at about 65%, which means we're pretty huge.

A website developed by Cary Huang called Scale of the Universe allows for an interactive experience, whereupon the user can scroll in and out, all the way from Quantum Foam to the very edges of the observable universe.

I love the diversity of objects included, and the animations and text descriptions round out the experience nicely. It's an awe inspiring depiction of humans and our impact, but also of the limitations of what we know and can experience.

The Earth at Night

This is an image of the world at night, thanks to NASA's Visible Earth, 2001. The various colors that can be seen are city lights, natural gas flares, wildfires, and lights from fishing fleets. (Disclaimer: Obviously, this is a compiled image since the earth is never all dark at once, nor is it flat...)

Entomology!

 

Thanks to xkcd!

10 Misconceptions Debunked

Hand Sanitizer

Hand sanitizers claim to kill ~99% of bacteria. How does this work? Well, alcohol kills bacteria exponentially. For example, after x amount of time, 90% are dead. After 2x that time, 99%, 3x, 99.9%, and so on. As you can see from that math, you'll never 100% sterilize something using alcohol - at least not in a practical way. However, as far as getting germs off your hands, 99.9% is good enough. You're not looking to sterilize your hands (which is impossible), you're looking to cut down the risk of infection.

The 10% survivors in each instance aren't resistant, they're just lucky. Maybe they didn't get the full exposure to the alcohol, they had a little extra water in them, or they were in a clump. The effectiveness of a sanitizer is always dependent on the surface to which it is applied. If the alcohol can't get to the bacterium, it can't kill it. As such, human skin provides a lot of nooks and crannies in which bacteria could not be reached by the alcohol very well. This is why alcohol based hand rubs are only recommended on non-soiled hands. They aren't designed to penetrate dirt and gunk. Just like the ratio of bleach to water has to increase depending on the amount of blood (or protein) in a spill.

Also, while alcohol kills everything, it doesn't efficiently kill everything. Bacterial spores, bacteria with thick capsules, and nonenveloped viruses are fairly resistant to alcohol. For this reason, alcohol is never used as the only method when something needs to be completely sterile - we use fire, 10% bleach, formaldehyde, gamma rays, or autoclaving instead. Labs also use the aseptic technique when surfaces need to be 100% sterile. Please see the CDC take on handwashing and hand sanitizer.