Astronomers use the term "light year" as a unit of measurement of the distance to far-off objects. Thus, for example, the closest star system to our Sun is Alpha Centauri which is said to be 4.37 light years away. A light year is the distance that light can travel during the course of one year. The speed of light is very great being 1,079,252,849 kph or (670,616,627 mph) and so a light year is a very, very long way indeed. And it is that large size that makes it a convenient unit of measurement for long astronomical distances.
You may already know that a light year is very big and maybe you can even quote its length in kilometers or miles. But do you really have a gut feel for its true size? In our everyday lives we tend to understand the real nature of distances based on our own experience of travelling using available transport. So, for example, we know that it takes only a few minutes to get to the local shops by car, a distance of (say) 5 kilometers. By passenger jet we can travel across a continent in a few hours. So maybe we can take the same approach to getting a feel for the distance of a light year? This program takes up the challenge using various representative forms of transport at ever increasing speeds. And having done that it then examines how those speeds affect the travelling time to a series of representative astronomical objects.
The program displays two main pages and some supporting notes.
You may already know that a light year is very big and maybe you can even quote its length in kilometers or miles. But do you really have a gut feel for its true size? In our everyday lives we tend to understand the real nature of distances based on our own experience of travelling using available transport. So, for example, we know that it takes only a few minutes to get to the local shops by car, a distance of (say) 5 kilometers. By passenger jet we can travel across a continent in a few hours. So maybe we can take the same approach to getting a feel for the distance of a light year? This program takes up the challenge using various representative forms of transport at ever increasing speeds. And having done that it then examines how those speeds affect the travelling time to a series of representative astronomical objects.
The program displays two main pages and some supporting notes.
The examples page
The upper part of this page allows you to explore how long it would take to travel the distance of one light year using various different modes of transport. These modes of transport fall into three categories viz. transport systems already available with current technology, transport systems using speeds that are theoretically possible but always below the speed of light, and science fiction transport systems using warp (or hyper) drive that use travel speeds under the speed of light but which nevertheless seem to exceed it.
For travel speeds at, or over, 1% of the speed of light the effect of time dilation is calculated so as to show how passengers will experience less travel time for a journey than is measured by an outside observer. The lower part of this page lets you determine how long it would take any one of those modes of transport to travel to a selected range of destinations within and without our Solar System. These range in distance from the Moon (384,000 kilometers away) to the Whirlpool Galaxy (23,000,000 light years). |
Do It Yourself
This page lets you enter your own values for travel speed and journey distance using the same three transport system categories used on the examples page. With it you can have fun exploring how long it would take to reach any destination using any nominated travel speed. For example you can determine how fast you need to go and, if necessary, what degree of spacetime warping is required so as to get to a specified destination within a reasonable time.
After using it for a while you may want to view the travel scenes in your favourite space operas in a new light! |
Notes
Video
You might like to view this video which demonstrates the use of the program. It runs for 24 minutes so you may not want to see the whole length but even viewing the first few minutes will give you a good idea of how to use the program.
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