Want to go to early Mars? How about Venus? Titan? Enceladus? Unless you've got a cool $100 billion sitting around, you probably can't. What you can do, however, is find someplace on Earth that looks the same. Last year I visited Hawaii Volcanoes National Park, likely a good analog for the volcanic environments that could have supported life on early Mars. This year I'll be joining some of my fellow astronomy and geology students for some field work in Yellowstone National Park.
It's been about a decade since my last trip to Yellowstone, but I remember many of its sights as if I'd just returned. One of Earth's most remarkable locations, it is hardly surprising that Yellowstone became the world's first national park in 1872. Since then it has wowed untold millions of visitors from nearly every nation on Earth. But it's more than just a pretty attraction - for decades it has been an important area for research in planetary science.
Its famous hot springs host a range of flora and fauna found in few other locations. These organisms live in water hot enough to boil. Such creatures are probably the only ones we have hope of finding elsewhere in the solar system. It's not just extreme temperatures that would challenge extraterrestrial life, though. Unusual and harsh chemical environments pose an obstacle to success; Yellowstone's sulfur-rich pools support some of the most unusual ecosystems on Earth.
It's not just the creatures which make Yellowstone interesting from a cosmic perspective, however. The entire park sits within the basin of a giant super-volcano. Volcanos helped shape early Earth and likely contributed to the development of Venus and Mars. Perhaps even the Moon once had volcanoes. Like Mars today, Yellowstone's volcano is (thankfully!) inactive. Yet its heat still drives hydrothermal activity that results in the park's spectacular geysers. This process might be similar to what is happening on Enceladus, where geysers shoot jets of water thousands of kilometers into space.
But let's be honest here. Even if Yellowstone resembled nowhere else in the solar system, I'd still be going. It's one of the most remarkable regions on Earth and a sight everyone should get to see. The park provides a vivid reminder of the incredible diversity of life and landforms that natural processes can generate.