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Question Your World: How Far Does Our Solar System Stretch?

Our lovely and comfortable home here on Earth is a long way away from the end of our solar system. Here on Earth concepts of boundaries involve rivers, lakes, mountains, human imposed borders, and so on. However, this is not how the limits of our solar system are established. There is not one point that defines the end, but there is definitely an end and it’s really far from here. Listen to the latest Question Your World Radio Report from the Science Museum of Virginia to learn more.

About 13 billion miles from home and well past all the other planets is an area known as the heliopause. This is the part of space where the solar winds, over a significant distance, slow down and are eventually stopped by the interstellar medium. Meaning this is as far as the impact of our sun can reach. This area is also the extent of our solar system, where the sun’s influence is gradually overcome by the stellar wind of particles from other stars.

The heliopause is so far away that we are only now getting real time data from the outskirts of our solar system courtesy of the Voyager 1 spacecraft. Traveling at a speed of nearly one million miles a day (912,000 miles per day to be exact) for the last thirty-five years, the Voyager 1 is finally approaching the heliopause. This cosmic explorer will become the first human made object to leave our solar system and remarkably, it still works!

The Voyager spacecrafts were launched in 1977 to gather more data on our solar system and then to continue to travel beyond the heliopause into the vastness of space. So, when will Voyager 1 reach another stellar system? Well, not for a while. In 40,000 years our then-power depleted spacecraft will be about 1.4 light years (8.23 TRILLION miles) away from its closest star. The spacecrafts have been loaded with plenty of analog data should they end up finding their way into the hands (or whatever appendages) of other beings way out there.

So, even at that amazing speed it will take a long time (huge understatement) for it to reach another stellar system. After all it took nearly thirty-five years just to approach the edge of our own cosmic neighborhood. Don’t forget, there’s a lot of space in space.

Article by Prabir Mehta, Science Museum of Virginia

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