planetary moon

Knowledge about oceans on other worlds starts with questions and answers about our own

To increase accessibility to our expedition, click to listen to the page text read aloud.


During our ship-to-shore broadcasts, we share with audiences the scientific objectives of Expedition 390 (and joint Expedition 393):

  • We seek to quantify the timing, duration, and extent of fluid moving through the aging ocean crust.
  • We seek to determine the microbes living in the sediment and basement and how they have varied in abundance and diversity over time and location.
  • We seek to investigate the responses of Atlantic Ocean circulation patterns and Earth’s climate system to rapid climate change (61 to 7 million years ago).

As we tour around the ship with our iPad, we interact with scientists and technicians to have them explain “what” they are doing and “how” they are carrying out their work. The one question we are almost immediately asked on each tour is “why” our work matters.

Our second expedition objective is an easy one for us to get students and adults of all ages excited about. As soon as we build the connection between microbes and the ocean and outer space, we can see the interest of our audience members ignite.


Oceans on other worlds

planetary moon
Enceladus Mosaic. From NASA/JPL/Space Science Institute.

NASA has discovered that ocean worlds are common in the galaxy. Even in our own solar system, certain icy moons (for example, Jupiter’s moon Europa, Saturn’s moon Enceladus) may have kilometer-thick oceans underneath their icy surfaces. In order to understand these planetary environments better, we start with our own closest to home – which means we focus our attention on learning more about what exists in our own ocean.

Scientists look at processes and features of Earth environments and then compare them to what we see on planetary bodies in our solar system and beyond. This is referred to as using and applying a planetary analog to understand other worlds. NASA uses three types of planetary analogs – geologic, astrobiological, and mission-specific. Astrobiologists are interested in determining what biological forms will look like on other planets, how they will function, and creating ways to detect their presence or activity. By using analogs from the microbial life we discover during scientific ocean drilling, we will be able to advance not only our own knowledge of Earth’s ocean system but what we might discover beyond our own planet.


Moving forward with analog research

Definition of biosignature = “A biosignature is any characteristic, element, molecule, substance, or feature that can be used as evidence for past or present life. It also needs to be something that can’t be made without the presence of life.”  —  from Astrobiology at NASA

In 2019, NASA announced its new Network for Ocean Worlds (NOW) initiative. NOW will “advance comparative studies to characterize Earth and other ocean worlds across their interiors, oceans, and cryospheres; to investigate their habitability; to search for biosignatures; and to understand life—in relevant ocean world analogues and beyond.” (Network for Ocean Worlds main page). The Woods Hole Oceanographic Institution (WHOI) is involved with NOW through the Exploring Ocean Worlds (ExOW) project. Their goal is to see how the oceanic physical and chemical processes that control material and energy influence the biosignatures left behind by life. WHOI is focusing their attention on ocean worlds that have liquid water in contact with basement material, because the Earth analog shows that fluid flow below the seafloor releases chemical energy stored in rock units.

It is important to note that no clear signs of extraterrestrial life have been detected (NASA), but the possibility of finding life in the universe has increased thanks to the ocean analog from our own planet. Samples from Expedition 390, which are collected from aa subsurface environment where basement is in contact with water, will advance our scientific knowledge and may help guide the direction for future astrobiology research as we continue to search for life in Earth’s deep ocean system and on other worlds.

two scientists preparing samples
On JOIDES Resolution, Yi Wang (left) and Mako Takada (right) working to prepare a basement rock sample from Expedition 390 for future microbiological analyses.


To learn more about understanding oceans on other planets, visit:

Laura Guertin
Passionate educator that cares deeply about increasing the scientific, geographic, digital and information literacies of students pursuing non-science degrees. Mentors undergraduate student researchers and emphasizes the connections between disciplines and STEM/non-STEM fields. Loves the outdoors and visiting natural National Parks. Always looking for ways to connect with my inner marine geologist.
More articles by: Laura Guertin

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