Should We Return to Uranus?

Source/Credit: A NASA composite image of Uranus taken from Voyager 2 and the Hubble Space Telescope.

In an earlier posting, I highlighted some scientific papers calling for a return to Neptune rather than Uranus, in part because of Neptune’s moon Triton. But what is the argument for a mission to Uranus? Below I highlight one of the papers submitted to the Planetary Science and Astrobiology Decadal Survey 2023-2032 arguing the merits of a NASA mission to Uranus.

The paper, “The Science Case for Spacecraft Exploration of the Uranian Satellites,” states:

The large moons of Uranus are possible ocean worlds that exhibit a variety of surface features, hinting at endogenic geologic activity in the recent past. These moons are rich in water ice, as well as carbon-bearing and likely nitrogen-bearing constituents, which represent some of the key components for life as we know it. However, our understanding of Uranus and its moons is severely limited by the absence of data collected by an orbiting spacecraft…

An orbiter would vastly improve our understanding of these possible ocean worlds and allow us to assess the nature of water and organics in the Uranian system, thereby improving our knowledge of these moons’ astrobiological potential. A Flagship mission to Uranus can be carried out with existing chemical propulsion technology by making use of a Jupiter gravity assist in the 2030 – 2034 timeframe, leading to a flight time of only ~11 years, arriving in the early to mid 2040’s (outlined in the Ice Giants Pre-Decadal Survey Mission Study Report:

The five large moons discussed in the paper are Miranda, Ariel, Umbriel, Titania, and Oberon. Titania and Oberon where the first to be discovered back in 1787, followed by the later discoveries of Ariel, Umbriel, and Miranda (in that order). Unlike the moons of other planets, the moons of Uranus are named after magical spirits in English literature.

All of these ocean worlds have gained greater interest as we learn about the dynamics of life on of our own planet. As noted in an article in the MIT Technology Review:

It was once thought the solar system was probably a barren wasteland apart from Earth. Rocky neighbors were too dry and cold like Mars, or too hot and hellish like Venus. The other planets were gas giants, and life on those worlds or their satellite moons was basically inconceivable. Earth seemed to be a miracle of a miracle.

But life isn’t that simple. We now know that life on Earth is able to thrive in even the harshest, most brutal environments, in super cold and super dry conditions, depths of unimaginable pressures, and without the need to use sunlight as a source of energy. At the same time, our cursory understanding of these obscure worlds has expanded tremendously. 

We have plenty of worlds to explore in our own solar system as other scientists continue their search for exoplanets and exomoons. The only question now is which local worlds will we visit in our next round of space missions.

Videos: Cool Worlds and Exoplanet Moons

Source: Image of Exomoons from Cool Worlds.

We have located exoplanets (planets around other suns) and even free-floating planets (planets without a sun), but what about exoplanet moons? A recent video from the YouTube channel Cool Worlds titled “We Discovered a New Exomoon Candidate! A Survey of 70 Cool Gas Giants,” discusses efforts by the Cool Worlds Lab to find these new moons. The Cool Worlds Lab, based at the Department of Astronomy, Columbia University, is a team of astronomers seeking to discover and understand alien worlds, particularly those where temperatures are cool enough for life, led by Professor David Kipping.

In this video, Professor Kipping discusses his lab’s discovery of exomoon Kepler-1625b-I in 2018. This is a Neptune-sized moon orbiting a Jupiter-sized planet that orbits about the same distant from its star as Earth orbits from our Sun. The video goes into the lab’s “Cool Giant Exomoon Survey” to locate additional exomoons orbiting Jupiter-sized cool giants further out from the host star. I do not want to give away the findings since you can see this for yourself, but it can be safely stated that a new exomoon candidate has been located (and shared in Nature). The exomoon’s designation is given away in the article’s title, so the secret is out.

Check out the Cool Worlds YouTube page for other fascinating videos.