There's just something exciting about fast-moving vehicles. Race cars zoom around the Indianapolis Motor Speedway at up to 230 mph. In China, the Shanghai Maglev Train goes cruising by on magnets at 286 mph. A British jet car holds the land speed record: 763 mph! 🏎️
If you want to reach truly blistering speeds, though, you've got to get off the ground. The high-altitude SR-71 spy plane from the 60's could go ten times the speed of a maglev train. Space rockets trying to leave Earth's orbit need to reach escape velocity, or about 25,000 mph! 🚀
Once you're out in space and away from the air resistance of Earth's atmosphere, you can really move. Plus, there are some very big objects in space that can help. NASA engineers use a trick called a "gravity assist" to help send spacecraft soaring. Scientists will aim the ship or probe toward a planet or moon. When the spacecraft gets close to the gravity of the much bigger object, it is caught and pulled along as the planet moves through space. It's like the difference between floating on an inner tube down a slow-moving river or being pulled by a speed boat! When the spacecraft moves past the planet and leaves its gravity, it is moving much faster than it was before.
That's how the fastest spacecraft is breaking speed records while it investigates the largest object in our solar system: the Sun! ☀️
The Parker Solar Probe currently holds the world record for the fastest human-made object ever. Launched in 2018, the probe swings between Venus and the Sun, getting a gravity assist from Venus with each pass. The solar probe has topped out at 430,000 miles per hour - fast enough to travel from Philadelphia to Washington, D.C. in one second!
The Parker Solar Probe holds another space record as well: it has traveled closer to the Sun than any other craft made by humans, getting about 3.8 million miles away.
Scientists have plans to make spacecraft that are even faster - perhaps even fast enough to reach another star within a human lifetime! A design called Breakthrough Starshot would use a sail with the mass of a paperclip 😱 and blast it with a super strong laser beam from Earth. It could reach 20% the speed of light! That means we would reach the nearest star within 20 years 💫
Unfortunately, Breakthrough Starshot is still just a design for now. We're getting pretty speedy in other areas, though. Here's a graph comparing the speeds of different objects to the speed of light.
If I brought this graph into the classroom, here are some questions I'd have to go with it:
💡What do you notice about the scale of the Y-axis? Why is this kind of scale needed for our data?
💡Scientists use scientific notation to express very large numbers in a way that saves space. For example, 559,000,000,000,000,000 would be 5.59 x 1017 in scientific notation. The decimal point is moved until there is just one digit to the left. The exponent on the 10 shows how many places the decimal moved. For example, 100 would be written as 1x102 and 10,000 would be written as 1x104. What is the speed of the Parker Solar Probe expressed in scientific notation? What is the speed of light shown in scientific notation?
💡At its launch, the New Horizons probe was traveling at a speed of 16.3 km/s. The craft did not reach its top speed until it received a "gravity boost" from Jupiter. How much faster did Jupiter cause this probe to travel compared to its launch speed?