Visualizing the Speed of Light

With the flip of a switch, your room can be instantenously flooded with brightness.

In fact, there is no noticeable lag effect at all.

That’s because emitted photons travel at 186,000 miles (300,000 km) per second, meaning it takes only 1/500,000th of a second for light to reach even the furthest part of an ordinary room. And, if it could go through the wall, it would orbit the entire planet 7.5 times in just one second.

Light Speed is Fast…

In our every day experiences, we never see light as having to “take time” to do anything. It’s inconceivably fast, brightening up everything in its path in an instant — and with a few odd caveats, scientists believe light speed to be the fastest-known achievable pace in the universe.

But what if we get out of our bubble, and look at light from outside the confines of life on Earth?

Today’s animation, which comes from planetary scientist Dr. James O’Donoghue, helps visualize the speed of light in a broader context. It helps remind us of the mechanics of this incredible phenomenon, while also highlighting the vast distances between celestial bodies — even in our small and insignificant corner of the solar system.

Light Speed is Slow…

Once a photon is sent into the vast abyss, suddenly the fastest possible speed seems somewhat pedestrian.

• Moon: It takes about 1.255 seconds for light to get from Earth to the moon.
• Mars: Mars is about 150x further than the moon — about 40 million miles (54.6 million km) in the closest approach — so it takes 3 minutes to get there from Earth.
• Sun: The sun is 93 million miles (150 million km) away, meaning it takes 8 minutes to see its light.

Let that sink in for a moment: the sun could explode right now, and we wouldn’t even know about it for eight long minutes.

Going Further, Taking Longer

If it takes light a few minutes to get to the closest planets, how long does it take for light to travel further away from Earth?

• Jupiter: The largest planet is 629 million km away when it’s closest, taking light about 35 minutes.
• Saturn: The ringed planet is about as twice as far as Jupiter, taking light 71 minutes.
• Pluto: It takes about 5.5 hours for light to go from Earth to the dwarf planet.
• Alpha Centauri: The nearest star system is 4.3 light years away, or 25 trillion miles (40 trillion km).
• Visible stars: The average distance to the 300 brightest stars in the sky is about 347 light years.

If you really want to get the feeling of how “slow” light really is, watch the below video and journey from the sun to Jupiter. It’s done in real-time, so it takes about 43 minutes:

So while light obviously travels at a ludicrous speed, it really depends on your vantage point.

On Earth, light is instantaneous – but anywhere else in the universe, it’s pretty inadequate for getting anywhere far (especially in contrast to the average human lifespan).

Watching the Sky Fall: Visualizing a Century of Meteorites

Astrophysicist Neil DeGrasse Tyson once said “The chances that your tombstone will read ‘Killed by an Asteroid’ are about the same as they’d be for ‘Killed in Airplane Crash’.”

Part of the reason for this is the Earth’s atmospheric ability to burn up inbound space rocks before they reach the surface, a process that ensures that most meteors never become meteorites.

Of the 33,162 meteorites found in the past 100 years, only 625 were seen. Today’s visualization from data designer Tiffany Farrant-Gonzalez groups these 625 observed meteorites by the year they fell, classification, mass, and landing location on Earth.

Asteroid, Meteoroids, Meteors, and Meteorites

Not all flying space rocks are the same. Their origins and trajectories define its type.

Asteroid: A large rocky body in space, in orbit around the Sun.
Meteoroid: Much smaller rocks or particles in orbit around the Sun.
Meteor: If a meteoroid enters the Earth’s atmosphere and vaporizes, it becomes a meteor, or a shooting star.
Meteorite: If a small asteroid or large meteoroid survives its fiery passage through the Earth’s atmosphere and lands on Earth’s surface.
Bolide: A very bright meteor that often explodes in the atmosphere, also known as a fireball.

Classification

This graphic classifies meteorites into four types based on their composition: stony, stony-iron, iron and other.

Top 5 Meteorites by Size

While half of all observed meteorites weighed less than 2.5 kg (5.5 lbs), there are a few exceptional ones that stand out. The graphic highlights the five largest meteorites ever observed, and when they fell:

Each category differs in their amount of iron-nickel metal and what they reveal about the early solar system.

Fireballs in the Sky: Bolides

Small asteroids frequently enter and disintegrate in Earth’s atmosphere randomly around the globe, creating fireballs known as bolides. NASA’s Near-Earth Object Program mapped data gathered by U.S. government sensors from 1994 to 2013.

Source: NASA

The data indicates that small asteroids impacted Earth’s atmosphere, resulting in a bolide (or fireball), on 556 separate occasions over a 20-year period. Almost all asteroids of this size disintegrate in the atmosphere and are harmless.

A notable exception was the Chelyabinsk event in 2013, which was the largest known natural object to have entered Earth’s atmosphere since the 1908 Tunguska event. A house-sized asteroid entered the atmosphere over Chelyabinsk at over 11 miles per second, and blew apart 14 miles above the ground.

The explosion released an energy equivalent to ~440,000 tons of TNT, generating a shock wave that shattered windows over 200 square miles—damaging several buildings and injuring over 1,600 people.

Look Out Above

While the night sky appears to be a beautiful tableau of the cosmos, these two visualizations paint a dramatic galactic battle. Rocks inundate our planet as it moves through the darkness of space. The resiliency of Earth’s atmosphere to erode these invaders has allowed life to flourish⁠—until the next big one comes through.

Remember the Dinosaurs?