Next year will be the first in 15 years that I do not have a cruise planned. Alvin will head home to Woods Hole, Massachusetts, for an overhaul (a 5- to 6-month process) and Atlantis for some much needed TLC. The one thing I can count on is that when I next set foot on this ship I will be home and among friends. I know that I speak for each and every one of the Science Party in saying thank you to the crew of R/V Atlantis and the Alvin Group for an outstanding cruise and in wishing each of them the very best for the holiday season.

To each of you out there on shore who have followed us during this extraordinary cruise: we thank you and hope that in letting you onto the ship and into our lives and our science, you have gained an appreciation for the importance of exploratory science and, more importantly, the process of science itself. From all of us aboard R/V Atlantis, we wish each of you the happiest of holiday seasons and following seas throughout the New Year.

As Extreme 2004 comes to a conclusion, I am finding it terribly hard to leave the R/V Atlantis. For three weeks now, the ship has been our "home" and the crew our "family." It will be very strange to go back to our lives on the shore. As I reflect back on what this experience has meant to me, I realize that there are many people to thank, some of them you know, some of them you don't.

First, there is Karen Romano Young, the other half of our "Dynamic Duo." Karen is a phenomenal writer, a great listener, and a friend. She actually brought me a present out here and left it on my desk for when I came back from my Alvin dive. It's a little submersible that we've had a lot of fun with.

Next, I'd have to thank our support team on shore (there are five of them) in the Marine Public Education Office at the University of Delaware. David Barczak is our Web site guru. He took all of the material that Karen and I sent back and turned it into the spectacular pages you have seen throughout the web site.

Pamela Donnelly has been sending us all of your questions for our "Write the Scientist" section. We thank her for coordinating the thousands of questions we received over the course of the expedition. Kimberly Doucette took care of all of the classrooms out there that followed us along. She handled the sending out of the Extreme 2004 guides and videos and took care of any issues that came up along the way. Kari Gulbrandsen did a superb job checking the accuracy of what Karen and I wrote and photographed. We appreciate the many times she made sure that we had our facts straight!

Finally, we thank Tracey Bryant who coordinates the Marine Public Education Office and all the countless tasks that she performed to make sure that Extreme 2004 ran smoothly.

Next, I'd like to thank all of the scientists who did more than just tolerate Karen's and my questions, pleas for photographs, and requests for just five more minutes of their time. Yes, these scientists truly embraced the idea that students were following along with our adventure. They even got excited when students suggested Extreme Experiments or asked really thought-provoking questions. I think you students may have given these scientists some ideas for future projects. I'd like to thank all of the scientists for their patience and efforts to make Extreme 2004 a great experience for all of the students.

My deepest appreciation goes out to the captain and crew of R/V Atlantis. While we were merely guests in your home for the past three weeks, you truly made us feel like family. I have never met a finer group of people. Another group that resides upon the ship deserves our gratitude: the Alvin Group. Expedition Leader Pat Hickey and the Alvin Group deserve our heartfelt thanks, for without them we would never be able to explore hydrothermal vents. They make all of this possible.

Next, I'd like to thank Dr. Craig Cary, our chief scientist, who gave me the opportunity to join Extreme 2004. I really cannot express in words what this experience has meant to me. I was floored by the crew, scientists, and the experience of being at sea. Then, the opportunity to dive to bottom of the ocean and see the abundance and diversity of life there has left me in awe of the ocean, the miracle of life, and the many discoveries we have yet to make.

Finally, I'd like to thank everyone that followed us along via the Web site. I was amazed at the responses we got from family and friends and thousands of students who followed along with our adventure day by day. We were inspired by your enthusiasm and your curiosity. If what we received from you all is any indication of the future of science, I look forward to amazing discoveries in the future.

For as Isaac Newton said, "What we know is but a drop. What we have yet to discover is an ocean."

This is Michael League signing off from R/V Atlantis, saying that this has truly been a pleasure. Over.

I sat up in the bow of R/V Atlantis this morning for the last time. I'm so torn. I long to be home, but my heart is so heavy about leaving this ship and everyone on it. I drop my hands over the railing and let the wind push them up and down, as if I was driving along the road on a summer night. For now, there are still a few more nautical miles to travel before we dock in San Diego this afternoon.

What a road! The jagged horizon of Baja California is off to starboard, its coastline veiled in the Pacific mist that sits on top of the water at different times of the day and season from here to Vancouver. Off to port, the ocean ripples away, wide and deep. For all the exploration I've done this trip, I am only a little bit closer to understanding its mammoth size. It's like trying to understand the air.

I'm a land person, used to traveling in two dimensions: X marks the spot where I am. Look at that X, and imagine another axis, one that passes through the center off the X straight at you, and extends behind the X, straight away. That's a third dimension, and giving directions — understanding the depth and width and length of the ocean — is like describing the air a bird flies through. Up, down, over, under, as well as right, left, starboard, port, North, South, East, and West.

Alvin Pilot Bruce Strickrott told me a story the other day about the Voyager II mission, in which NASA sent an unmanned spaceship out beyond the edge of the solar system, where it would continue to send back pictures of everything before it for as long as we could receive transmissions. Scientist and writer Carl Sagan was one of the people involved in the effort to change those plans, and he wrote about this controversy surrounding Voyager's pictures.

How could Voyager II go out to the edge of the solar system and only look outward, transmitting its new discoveries, without once turning around and looking back toward Earth? How could NASA pass up this opportunity to get an extraterrestrial's-eye view of our solar system? After painstaking debate, Voyager was reprogrammed to look over its shoulder before heading out of the solar system.

The results were both revealing and heartbreaking. It was just what you'd expect, really, only so dramatic that it brings a lump to your throat: Mercury was a dot, Venus a spot, Earth a blue blot, Mars a red blot ... and so on. How can our enormous solar system — far too large for any of us to consider traveling across — fit into the frame of a photograph?

The ocean can, too. It's what makes a view back at our planet predominantly blue. After living on the ocean for three weeks and having the chance to dive down through it, I see the ocean differently. Still, I have to remind myself when I look at the surface that there is much, much more. What if you had never been to Earth and looked at Voyager's photographs? What if your only view of Earth was the one from the Apollo missions — that big, blue, swirly marble — or the view from the space shuttle, which shows the glow of our atmosphere? What would you think the ocean was then?

For me, there is nothing more exciting and beautiful than the ocean. There is so much happening and so much to learn. It won't happen unless people ask questions and are willing to do whatever they can to answer them. The more we know, the more we realize how much we don't know. Let it continue! And please, consider a career in the sciences.

I think the discoveries made during the Extreme 2004 mission have changed many viewpoints. I'm glad to have made the voyage and to have had the opportunity to share it in writing and in pictures.

Thanks to the Woods Hole Oceanographic Institution (WHOI). Thanks to Captain George Silva and the crew of R/V Atlantis, Pat Hickey, and the Alvin Group, and all of the Extremely wonderful and brilliant scientists.

Thanks to the National Science Foundation for supporting our efforts and thanks to Dr. Craig Cary for inviting me to come aboard as a shipboard education coordinator.

Thanks to the wonderful and courageous Michael League, who fixed my computer and my facts more times than I can tell you. Mike's a good scientist, a great sport, and a fine person with so many talents that it's anyone's guess which way he's going to increase his fame. Thank you, Mike, for being my buddy. Come visit me, and I'll buy you ice cream.

Most of all, thanks to all the students and teachers who participated. We have all been inspired by your questions, notes, experiments, e-mails, poems, and every other sign that you were following along with us and soaking up ocean sciences. This mission is proof that discovery requires all kinds of people and all kinds of minds and hearts.

This is my last transmission from R/V Atlantis. Over to you.