Looking Out Is Looking Back...in a VERY Big Place

Part I

In today's world, travel is made easy by jet aircraft, high-speed trains, and interstates on which cars may travel at high rates of speed. If you have relatives in a city 200 kilometers away, you can be at their house in only 2 hours by car if you travel at a speed of 100 kilometers per hour. How do we know this? By using the formula t = d/r (where t = time, d = the distance traveled, and r = the rate at which we travel), we can calculate our travel time. Let's investigate! What if those relatives that you wanted to visit lived 400,000 km away on the Moon? How long would it take to get to their house if you traveled by car at 100 km/hr?

2. The distance that you must travel to get to a lunar relative's house is nothing compared to the distance you must cover in order to visit a relative on Pluto. Pluto is 6,000,000,000 km from Earth. If you travel at 100 km/hr, just how long would it take you to reach our most distant planet? There are only 8760 hours in a year. How many years would it take you to reach Pluto? (You must REALLY like these relatives a lot!)

 

 

 

 

3. Perhaps we could reach Pluto in a more reasonable amount of time if we journey by jet. A jet travels at 1000 km/hr. At this faster speed, what is our travel time to Pluto? How many years will it take us?

Once you get outside of our solar system, the distances between objects become absolutely astronomical! It would be very difficult to do mathematical calculations using such large numbers. Scientists therefore rely on a unit called a light-year to describe the distance between the farthest objects in our Universe. A light-year is equal to 9,500,000,000,000 (9.5 trillion) km and is the distance that light travels in one year. A light-year can be expressed in scientific notation as 9.5 x 10¹² km.

4. The star outside of our solar system that is closest to Earth is Alpha Centauri C. It is 40,000,000,000,000 (40 trillion) km away. How many light years is that? If we hopped aboard our jet, how long would it take us to get to Alpha Centauri C? How many years would that take? (Can you imagine what you'd need to pack?)

 

 

 

 

 

 

5. As an extra challenge, calculate the time it would take to reach Betelgeuse, a red giant located 600 light years away. Traveling at 1000 km/hr. By jet, how long would it take to reach Betelgeuse? How many years is that? Did you know that by the time you got there, Betelgeuse would no longer be the red giant we know today? Betelgeuse is in the dying phase of its lifecycle. With a mass 1000 times that of the Sun, if Betelgeuse was put in the middle of our solar system it would extend all the way out to Jupiter's orbit! As a supermassive star, the next step in Betelgeuse's lifecycle will be a supernova. This is expected to occur within the next 10,000 years. (Maybe this trip is not well advised!)