Could Aliens Travel to Earth? Scientists Explain the Big Challenges
Scientists use math and physics to explore whether aliens could overcome the huge barriers to reach our planet.
Scientists are asking a big question: could aliens actually visit Earth? After the government released videos of mysterious flying objects, experts want to know if travel between stars is really possible. An aerospace scientist who designs spacecraft is using math and physics to find answers.
The biggest problem is distance. The nearest star to our Sun is 4.25 light-years away, which equals 25 trillion miles. If Earth were the size of a pea, that star would be as far as New York is from Australia. Any aliens would need to travel this incredible distance to reach us.
Scientists think the fastest realistic speed for space travel is about 19,000 miles per second. At this speed, a journey of 10 light-years would take 100 years. Getting a spaceship to move this fast is extremely difficult and requires solving many engineering problems.
The fuel problem is huge. Spaceships need fuel to speed up and slow down, but carrying fuel makes them heavier. This means they need even more fuel, creating a snowball effect. Chemical rockets like we use today would need more fuel than exists in the entire universe for such a trip.
At this speed, a journey of 10 light-years will take approximately 100 years to complete.
Comprehension quiz preview
1. How far away is Proxima Centauri, the closest star to our Sun?
2. What does the word 'antimatter' mean in this article?
3. Why would aliens probably need to travel for many years to reach Earth?