It’s All Relative

• By Sara Mitchell
• April 30, 2009
• Comments Off on It’s All Relative

Astronomers have a funny way of talking about things sometimes. Take temperature, for example. When scientists say something is “hot,” they aren’t talking about “hot” like the Sahara desert, or “hot” like the seat of your car on a summer day. No, they’re talking about an unimaginably high temperature beyond that which any humans (or spacecraft) can stand. Then when they say “cold,” they might mean an equally extreme temperature… or a temperature that doesn’t seem that cold to our bodies. Compared to the searing heat of the Sun, the Earth’s climate seems downright frigid!

It’s all relative, really. Words just don’t mean the same thing when applied to the extremes of space. Astronomers would say the Sun is a “small” star. But… on a human scale, the Sun is huge! It’s just that, compared to other stars, ours is pretty average. A truly “large” star (in astronomical terms) would swallow the Earth and other inner planets whole. So I’m pretty happy that the Sun is “small.”

Space is big and full of extremes – the largest objects we’ve ever seen, the hottest (and coldest) climates, and distances measured in kilometers with a lot of zeros at the end. This can make it difficult to imagine what it’s like out there, what’s out there and how it all fits together. This is where good models come into play. There are a lot of different ways to represent the objects in space in ways that make their size, distance, and other characteristics more relatable.

During the 100 Hours of Astronomy, we partnered with a community group to offer special tours of the solar system. Just outside of Baltimore, Maryland, there is a permanent scale model of the solar system along a popular trail frequented by cyclists and day-hikers. The trail shrinks the solar system from 3.7 billion miles down to a much more manageable 4.6 miles, and has stations to show the locations of planets along this scale. At our event, we added scientists at each stop to share information and materials along the trail. Blueshift’s own Francis Reddy took the tour… and shares his experience in today’s episode.

Check out Stroll the Solar System, released today!