In today’s Bulldog roundup of science and technology news from around the world:

  • Zero-emission boat prepares for round-the-world odyssey
  • Scientists: Moon over the hill at 4.51 billion years old
  • Twitter: Obama’s ‘thank you’ tweet his most popular ever
  • 1 Japanese, 2 Americans win Crafoord science prize 

The details:

  • Zero-emission boat prepares for round-the-world odyssey

The first self-sufficient boat powered only by emission-free energy will start a six-year trip around the world in the spring.

Energy Observer, a former multi-hull race boat converted into a green vessel equipped with solar panels, wind turbines and a hydrogen fuel cell system, will be powered by wind, the sun and self-generated hydrogen.

[VIDEO: Watch a video overview at https://www.youtube.com/watch?v=y6AmSDMLjus ]

The 5 million euro ($5.25 million) boat, which is currently in a shipyard in Saint-Malo, will set sail from the Brittany port and will make its first of 101 stops across 50 countries in Paris as part of a six-year circumnavigation.

“This boat will demonstrate that there are many solutions for energetic transition,” said French environmentalist Nicolas Hulot, who attended the project presentation on Wednesday at the UNESCO headquarters. “All solutions are within nature.”

Designed in 1983 under the supervision of Mike Birch, the boat enjoyed a successful career in open-sea sailing races, including winning the Jules Verne Trophy in 1994, with Peter Blake at the helm. The Energy Observer project was conceived in 2015 by skippers Frederic Dahirel and Victorien Erussard, with scuba diver and filmmaker Jerome Delafosse also behind the project.

“I’m passionate about new technologies,” Erussard said. “Building a self-sufficient boat could have seemed utopian, but this is going to be an incredible vessel. It’s very promising for the future.”

  • Scientists: Moon over the hill at 4.51 billion years old

It turns out the moon is older than many scientists suspected: a ripe 4.51 billion years old.

That’s the newest estimate, thanks to rocks and soil collected by the Apollo 14 moonwalkers in 1971.

A research team reported Wednesday that the moon formed within 60 million years of the birth of the solar system. Previous estimates ranged within 100 million years, all the way out to 200 million years after the solar system’s creation, not quite 4.6 billion years ago.

The scientists conducted uranium-lead dating on fragments of the mineral zircon extracted from Apollo 14 lunar samples. The pieces of zircon were minuscule — no bigger than a grain of sand.

“Size doesn’t matter, they record amazing information nonetheless!” lead author Melanie Barboni of the University of California, Los Angeles, said in an email.

She noted that the moon holds “so much magic … the key to understand how our beautiful Earth formed and evolved.”

The moon was created from debris knocked off from Earth, which itself is thought to be roughly 4.54 billion years old.

  • Twitter: Obama’s ‘thank you’ tweet his most popular ever

President Barack Obama’s tweet following his farewell address to the nation has become the most popular post on the presidential account.

Obama tweeted from the @POTUS account Tuesday night: “Thank you for everything. My last ask is the same as my first. I’m asking you to believe_not in my ability to create change, but in yours.”

As of midday Wednesday, the message had been retweeted more than 500,000 times. Twitter spokesman Nick Pacilio says that outperforms his previous top tweet, a message posted after the Supreme Court’s June 2015 decision to overturn state bans on gay marriage.

The @POTUS account has more than 13 million followers. Obama’s personal @BarackObama account has more than 80 million followers.

  • 1 Japanese, 2 Americans win Crafoord science prize

A Japanese and two American scientists have been awarded the 2017 Crafoord Prize for fundamental discoveries in immune regulation.

The prize committee says Shimon Sakaguchi of Osaka University, Fred Ramsdell from the Parker Institute for Cancer Immunotherapy in San Francisco, and Alexander Rudensky of the New-York-based Memorial Sloan Kettering Cancer Center share the 6 million Swedish krona ($660,000 award.

They were cited “for their discoveries relating to regulatory T cells, which counteract harmful immune reactions in arthritis and other autoimmune diseases.”

The prize is awarded in one discipline each year — this time in Polyarthritis. The Royal Swedish Academy of Sciences gives it annually to honor achievements not always covered by its more famous Nobel Prizes. It was named after Holger Crafoord, the Swede who designed the first artificial kidney.