Six Degrees of Separation: Venus flytrap -> Hubble telescope

aramakrishnan6
Dec 7, 2020
5 min read

The six degrees of separation theory grew out of a psych study conducted by Stanley Milgram in the 1960s. According to Milgram, every person on Earth is connected by a chain of people approximately six links long. I’m putting Milgram’s idea to the test using science instead of people – and instead of human links, Wikipedia links.

Here’s the idea: I choose two seemingly unrelated topics, and open the Wikipedia page for the first topic. Using only the terms linked in the article, I try to get from the first topic to the second in six clicks or less. We’ll play matchmaker using science and a little bit of luck, and I’ll explore the connections between each step I hit along the way.

In my first WikiRace, I’ll be connecting the Venus flytrap to the Hubble Telescope. Read on to see if I’m able to do it in six clicks or less.

Venus flytrap

You may know the Venus flytrap as a meat-eating plant that snaps its jaws shut to trap and digest insects. But did you know that one of the nutrients that helps it snap closed on its prey is also found in the milk we drink? A recent study in Nature Plants tried to understand the Venus flytrap’s highly specific intruder detection system—that is, how it figures out if the activity on its surface is an inedible rock or a juicy insect fit for a midday meal—and identified calcium as a key player.

According to the study, the flytrap doesn’t snap closed the instant it registers any activity on its two jaw-like leaves. Instead, motion on its surface causes the release of calcium across the flytrap’s leaves, serving as a reminder to the plant that something was recently on it. If the flytrap’s surface feels another touch within 30 seconds of the initial calcium release, its jaws snap shut on its prey. Why does it take two taps to trigger the Venus flytrap’s signature prey-snatching move? To make sure that the object lurking on its surface is not a still leaf, but an insect worthy of digestion that can move around the plant’s surface.

Venus fly trap → Photosynthesis

My first click takes me to photosynthesis, which may seem counterintuitive: after all, Venus flytraps digest insects for food, and photosynthesis is the process by which plants cook up their very own food using sunlight, water, and carbon dioxide. Surprisingly enough, Venus flytraps undergo photosynthesis, too.

To survive, Venus flytraps need both energy and nutrients like nitrogen, calcium and potassium. Most fly traps prefer to grow in environments with very acidic soil, meaning that these essential nutrients are far and few between. To compensate for this, they evolved to start eating insects that provide them with all the nutrients that their soil is missing. But, the Venus flytraps still need energy, which they get in the same way as all our leafy greens: by employing photosynthesis to convert sunlight into an energy molecule that we use too, called ATP.

Photosynthesis → Oxygen

Plants produce oxygen when they undergo photosynthesis. Funnily enough, we can thank a photosynthetic organism for introducing the very first bit of oxygen to the air about 2.4 billion years ago. This organism, called cyanobacteria, is likely responsible for what scientists call the Great Oxidation Event: the moment where a cyanobacteria made its own energy using photosynthesis, made oxygen as a side product, and disposed of it in the air. As more cyanobacteria photosynthesized, oxygen accumulated in the air, allowing us to live and breathe today.

Oxygen → Earth’s atmosphere

One of the most important places oxygen appears in our atmosphere is in the ozone layer, located about 9 to 18 miles above the Earth’s surface (for comparison, 18 miles is about 317 football fields). Ozone is a molecule that’s made up of three oxygen atoms joined together. You may have heard that the ozone layer prevents harmful radiation from reaching the Earth’s surface, keeping us safe. How exactly does it do this?

Ozone absorbs ultraviolet rays that come from the sun and can cause sunburns and skin cancer. When these UV rays beam in the direction of Earth, they collide with ozone particles in the atmosphere, splitting the three-oxygen ozone into one O2 molecule and a single oxygen atom. This interaction allows the ozone molecule to absorb UV radiation and convert it into heat, preventing it from passing through Earth’s atmosphere and harming us.

We damage the ozone layer by releasing chemicals called chlorofluorocarbons (CFCs) into the atmosphere. CFCs are found in aerosols and fluids used in refrigeration. Once they enter the ozone layer, CFCs can release chlorine atoms that break up ozone by removing one of its oxygen particles. The less ozone in the atmosphere, the less protected we are from the sun’s UV rays.

Earth’s atmosphere → International Space Station

The International Space Station is a space laboratory that orbits the earth in one of the outer layers of Earth’s atmosphere. Up to six crew members can stay in the space station at a time, plus the occasional visitor. The ISS is used to conduct research in space, as well as see how the human body reacts to being in space for long periods of time.

The Space Station is able to circle our planet without falling back down to Earth or floating off into deep space. The reasoning for this dates back to Isaac Newton and his theories about gravity. In order to stay in orbit, a space station like the ISS needs to fight the pull of gravity yanking it back down to the ground. To do this, the ISS moves faster. If the ISS moves at exactly the right speed, the perfect combination of its forward motion and the downward pull of gravity creates its circular path around the planet Earth.

International Space Station → Hubble Telescope

The Hubble Space Telescope is located in the exosphere—the outermost layer of Earth’s atmosphere. Its location in space allows scientists to examine not only the visible light of our universe, but also the ultraviolet and infrared rays that would be filtered out by our atmosphere if we tried to measure them way down on Earth.

Just like the International Space Station, the Hubble Telescope lets scientists get a little closer to understanding how our universe works. Most recently, scientists compared Hubble’s pictures of a planetary nebula nicknamed the Stingray nebula from 1996 and 2016, and found that its characteristic blue brightness and wavelike edges have all but disappeared. The dimming of a nebula isn’t something the scientists were expecting: it hints at some kind of structural change within Stingray that is happening over time.

Planetary nebulas are gas clouds released by stars near the end of their lives. The star at the center of the Stingray nebula happens to be cooling, causing it to release less energy and dimming the planetary nebula’s brightness. Thanks to Hubble, scientists can monitor the nebula’s progress over time as it continues to fade, and use its pictures to understand how planetary nebulas grow and change in space.

The full path from Venus flytrap to the Hubble Space Telescope is: