You might have heard about this little thing that’s been tearing up the Internet recently: Pluto. Yes, that cold, distant world that was a planet, then wasn’t, and now is something that just about anyone with a toe in science wants to talk about.
And for good reason! It turns out that Pluto is not a barren rock as some may have suspected. It is -- or at least has been – geologically active with mountains and different kinds of terrain. No matter how you want to classify Pluto (as a planet, ex-planet, dwarf planet, ice dwarf, Kuiper Belt Object, Disney dog...), using the word “interesting” is a good place to start.
NASA’s New Horizons spacecraft captured this data on July 13, 2015 at 476,000 miles (768,000 kilometers) from the surface of the ice dwarf. Image Credit: NASA/APL/SwRI
How are we learning so much about Pluto? It’s thanks to NASA's New Horizons spacecraft. New Horizons didn’t, however, get to land on Pluto and start digging around. Rather, it flew by at a pretty fast speed. It used a suite of instruments, most of which detect different types of light, to observe Pluto and its moon Charon with unprecedented clarity and ability. There are instruments on New Horizons that can see exquisitely in visible light, ultraviolet light, and another that can detect radio waves. There are also spectrometers that can dissect light at individual wavelengths to learn more about what’s happening on and around Pluto.
There are some good explanations as to why we needed to send New Horizons billions of miles to get a better look at Pluto. The upshot is that Pluto is really small and quite far away, which means it reflects very little sunlight. Planets don’t emit much of their own light, at least in the visible light realm – they need to reflect it from an external source such as the Sun. Even the mightiest visible light telescope, the Hubble Space Telescope, can’t get better images if there is not enough light to detect from a body like Pluto. (For a better and fuller description of the situation involved in observing Pluto, take a look at Travis Rector’s post on our sister blog.
While we wait for the next exciting announcement to come from the New Horizons team this Friday and the ones surely to follow after that, take a moment to realize the language that the Universe most frequently speaks to us in: light. Whether that light comes in the form of radio waves or X-rays or the kind we can see with out eyes, it is most often the way we learn about the wonders all around us and across the cosmos.