What do astronomers do the day after a 13-hour trip up and down Mauna Kea, Hawaii? A few of them, led by expert volcanologist Stephen James O'Meara, spent the day exploring erupting lava from the Kilauea volcano. Each month, Steve writes the highly popular "Stephen James O'Meara's secret sky" in Astronomy, and he is renowned as a skilled astronomical observer. Less known to Astronomy readers is the fact that Steve and his wife Donna are highly accomplished students of Hawaii's volcanoes; indeed, they live close to Kilauea in Volcano, Hawaii.

After spending the first half day trudging around Hawaii Volcanoes National Park, I met Steve at the park headquarters, along with several others, and we drove a long distance to get as close to the active flow as we could. Joining us were Astronomy Contributing Editor Martin Ratcliffe and his wife; journalist Govert Schilling and his daughter; and planetarium expert and writer Carolyn Collins Peterson and her husband. We packed lots and lots of water, our cameras, and a few snacks, and started the 1 1/2-mile hike across fresh lava, seeking as many hot spots as we could find.

It made for a sensational day. It's slow going, as fresh lava can be both hilly, fractured, fragmented, and extremely sharp, and also glassy and somewhat slick. Careful foot positioning is absolutely necessary. We spent the first 2+ hours walking over to several vents and found active, bubbling lava in many, many spots. The visual sensation of seeing it is cool, but so is the audio that accompanies it: hissing, cracking, popping.

After finding the main flow and walking down to the cliffs overlooking the ocean, we stopped for a snack-dinner before photographing the lava flow hitting the water as dusk washed over us and a nearly Full Moon rose. The long walk back seemed a small price to pay for a fantastic, unforgettable experience in nature.

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