A very small instrument has a big job ahead of it: measuring all Earth-directed energy coming from the sun and helping scientists understand how that energy influences our planet's severe weather, climate change and other global forces.

About the size of a shoebox or gaming console, the Compact Total Irradiance Monitor (CTIM) is the smallest satellite ever dispatched to observe the sum of all solar energy Earth receives from the sun—also known as "total solar irradiance."

Total solar irradiance is a major component of the Earth radiation budget, which tracks the balance between incoming and outgoing solar energy. Increased amounts of greenhouse gases emitted from human activities, such as burning fossil fuels, trap increased amounts of solar energy within Earth's atmosphere.

"After Euclid's lifetime, it will just be floating in space. What if future beings found Euclid? How would they know anything about the humanity of the people?" says Tom Kitching, lead scientist of Euclid's VIS instrument.

The team behind ESA's Euclid mission has come together to create something special—a personal and collective galaxy-shaped fingerprint painting that has been attached to the spacecraft ready to launch into space. The collaborative nature of the artwork reflects the collaborative nature of the Euclid project overall; in both cases, people have come together to build something unique.

The Fingertip Galaxy was created by visual artist Lisa Pettibone and Euclid instrument scientist Tom Kitching. Since the very first fingerprint was pressed down in 2019, over 250 scientists and engineers have contributed to the piece of art.

So why a galaxy? Euclid is a galaxy-imaging machine that will observe billions of galaxies out to 10 billion light-years to make a 3D map of the Universe. The mission's ultimate aim is to explore dark matter and dark energy.

"Although Euclid has always been beautiful in concept and materials, it didn't really say anything about the people involved and humanity as a whole.

NASA has recently announced US$600,000 (£495,000) in funding for a study into the feasibility of sending swarms of miniature swimming robots (known as independent micro-swimmers) to explore oceans beneath the icy shells of our Solar System's many "ocean worlds". But don't imagine metal humanoids swimming frog-like underwater. They will probably be simple, triangular wedges.

Pluto is one example of a likely ocean world. But the worlds with oceans nearest to the surface, making them the most accessible, are Europa, a moon of Jupiter, and Enceladus, a moon of Saturn.

Life inside ocean worlds

These oceans are of interest to scientists not just because they contain so much liquid water (Europa's ocean probably has about twice as much water as the whole of Earth's oceans), but because chemical interactions between rock and the ocean water could support life. In fact, the environment in these oceans may be very similar to that on Earth at the time life began.