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5 Most Important Lessons from “Cosmos”

"Cosmos" may end on Sunday, but its lessons will keep us thinking for a long time to come.

Photo Credit: Vadim Sadovski/


Sunday marks the finale of Neil deGrasse Tyson’s “Cosmos: A Spacetime Odyssey.” Though the wonderful hours of being dazzled, stunned and educated by Tyson and his “Ship of the Imagination” are coming to a close, there is still plenty about our cosmos left to ponder. (Let’s face it, we’ll probably rewatch the series and learn something new with each subsequent viewing.)

Here are the most important scientific lessons from our astrophysicist pal, Neil deGrasse Tyson.

1) It’s okay not to know all of the answers.

While it isn’t an eye-opening, earth-shattering revelation, knowing it’s okay not to have all the answers may be one of the most important lesson from “Cosmos.” If humans say “I don’t know,” then scientists can work on asking, “Why?” and then testing to solve the mystery.

“It’s OK not to know all the answers,”  Tyson explains to the audience. “It’s better to admit our ignorance, than to believe answers that might be wrong. Pretending to know everything, closes the door to finding out what’s really there.”

2) Climate change is happening, and it’s manmade.

Climate change is a topic Tyson tackles in  several episodes. His most shocking and thorough admonition comes in Episode 12, “The World Set Free,” which tells the tale of two planets, Venus and Earth.

Though its sweltering climate was not caused by manmade forces, Venus is still a cautionary tale of a greenhouse-gas overload. The amount of carbon dioxide in Venus’ atmosphere has turned the planet into an inferno. Even lead (melting point: 621.5°F) is a liquid on Venus. Tyson explains how, on Earth, humans have added 400 billion tons of CO2 into the atmosphere since Carl Sagan’s original “Cosmos.” While a climate as extreme as Venus’ is unlikely in Earth’s near future, we’re certainly doing everything we can to catch up to our cosmic neighbor.

Tyson then refutes many arguments made by climate deniers:

Q: Could the carbon dioxide be coming from volcanoes?
A: A very small portion is, but this gas is slightly different than that of burning coal or fossil fuels, so scientists can recognize that most comes from man-made causes.

Q: But this winter was so cold. If scientists can’t even predict the weather, how can they predict climate change?
A: Well, climate and weather are two different things. Weather events are short-term patterns in the atmosphere, and climate is a long-term trend.

Watch the clip  here.

3) Evolution: How did we get here?

This lesson may seem like an obvious one. However, with  creationists up in arms over the show’s depiction of evolution, it turns out it was an important one.

From the first episode of “Cosmos,” Tyson addresses evolution, and he continues to throughout the series. Evolution as a scientific theory is often vilified by religious groups who advocate for a strict interpretation of the Bible. However, it is important to Earth’s future that folks understand the planet’s past — patterns of climate, examples of extinction, natural selection and how humans came to be. Life today could not have happened without the evolution that happened slowly over the 4.5 billion years of Earth’s history.

The future of our planet relies on understanding how genes changed and mutated to fit their surroundings. An example comes from Episode 9, “ The Lost Worlds of Planet Earth.” This episode took viewers through the history of our Earth, preserved through fossils, and layers of rock. Tyson explains the evolution of plants: A new material “lignin,” allowed plants to grow taller and brought about the rise of the trees. Unfortunately, it took much longer for organisms to evolve to be able to decompose lignin, and the solidification and burying of non-decomposed trees is why the planet has coal.