On this day in space! March 25, 1655: Christiaan Huygens discovers Saturn's moon Titan

News
By last updated

On March 25, 1655, Saturn's moon Titan was discovered by the Dutch scientist Christiaan Huygens.

On March 25, 1655, Saturn's moon Titan was discovered by the Dutch scientist Christiaan Huygens (a name that you've probably heard mispronounced as "Hoy-gens").

Titan is the largest moon of Saturn and it was the first of 62 moons to be found orbiting Saturn. Huygens discovered Titan using a telescope he designed himself. While looking at Saturn's rings, he noticed a bright and tiny dot nearby.

A composite, infrared view of Saturn's moon Titan as imaged by NASA's Cassini spacecraft in 2015. (Image credit: NASA/JPL/University of Arizona/University of Idaho)
Related stories

— Titan Landing Pictures by Huygens Spacecraft

— Amazing Photos: Titan, Saturn's Largest Moon

— Titan, Saturn's Largest Moon, Explained (Infographic)

Huygens suspected it was a moon, but just to be sure, he kept watching it for a few days. He confirmed that the tiny speck was orbiting Saturn and therefore must have been a moon.

More than 300 years later, the European Space Agency sent a spacecraft to Titan and named it after him.

On This Day in Space: See our full 365-day video archive!

Join our Space Forums to keep talking space on the latest missions, night sky and more! And if you have a news tip, correction or comment, let us know at: community@space.com.

Hanneke Weitering
Hanneke Weitering
Contributing expert

Hanneke Weitering is a multimedia journalist in the Pacific Northwest reporting on the future of aviation at FutureFlight.aero and Aviation International News and was previously the Editor for Spaceflight and Astronomy news here at Space.com. As an editor with over 10 years of experience in science journalism she has previously written for Scholastic Classroom Magazines, MedPage Today and The Joint Institute for Computational Sciences at Oak Ridge National Laboratory. After studying physics at the University of Tennessee in her hometown of Knoxville, she earned her graduate degree in Science, Health and Environmental Reporting (SHERP) from New York University. Hanneke joined the Space.com team in 2016 as a staff writer and producer, covering topics including spaceflight and astronomy. She currently lives in Seattle, home of the Space Needle, with her cat and two snakes. In her spare time, Hanneke enjoys exploring the Rocky Mountains, basking in nature and looking for dark skies to gaze at the cosmos. 

You must confirm your public display name before commenting

Please logout and then login again, you will then be prompted to enter your display name.

More about space shuttle
closeup photo of the black and white nose of a space shuttle mockup

Full-size mock space shuttle makes first move towards Downey display
two construction workers pose on steel beams atop a building in a sunny city

Signed steel beams 'top off' L.A. home for space shuttle Endeavour
a sunrise on the left over water and a quaint lighthouse in the foreground on the right.

Best places in the US and Canada to see rare 'double sunrise' during partial solar eclipse on March 29
See more latest
Most Popular
a sunrise on the left over water and a quaint lighthouse in the foreground on the right.
Best places in the US and Canada to see rare 'double sunrise' during partial solar eclipse on March 29
Scenic view of mountains against sky at night, Horseshoe Bend, Idaho in the U.S.
Aurora alert! Moderate geomagnetic storm could spark northern lights as far south as New York and Idaho tonight (March 25)
A bunch of white-domed observatories under the starry sky. The Milky Way's heart arches over them all. To the right, the blood moon.
Dazzling photos of this month's total lunar eclipse showcase a blood red moon near the Milky Way's heart
An incredible image of a mystery blue spiral that appeared in the skies over Europe on Monday (March 24). This image was captured by Daniel Puchalski from Poland.
Mysterious blue spiral spotted over European skies. What was it? (photos)
a rectangular satellite in orbit above earth
Space pirates already have their sights set on the 'high seas' of Earth orbit. Can we stop them?
NASA’s James Webb Space Telescope observed Herbig-Haro 49/50, an outflow from a nearby still-forming star, in high-resolution near- and mid-infrared light. The young star is off to the lower right corner of the Webb image.Intricate features of the outflow, represented in reddish-orange color, provide detailed clues about how young stars form and how their jet activity affects the environment around them. A chance alignment in this direction of the sky provides a beautiful juxtaposition of this nearby Herbig-Haro object (located within our Milky Way) with a face-on spiral galaxy in the distant background. Image released on March 24, 2025.
'Cosmic tornado' swirls in breathtaking new James Webb Space Telescope image
two 'horns' appear in the lower portion of the image, showing what the solar horns look like at sunrise during the partial solar eclipse.
Rare 'solar horns' will appear during partial solar eclipse on March 29 — Here are 6 of the best places in the US and Canada to see the unusual phenomenon
Artist's illustration of an Artemis astronaut stepping onto the moon.
NASA says removal of 'first woman, person of color' language from Artemis websites 'does not indicate' moon mission crew change
a fashion doll is shown in and outside of its box with an inset showing the text on the back of the box
New Barbie doll celebrates 60 years as an astronaut, but forgets when humans first flew into space
A SpaceX Falcon 9 rocket launches the classified NROL-69 mission for the U.S. National Reconnaissance Office from Cape Canaveral Space Force Station in Florida on March 24, 2025.
SpaceX launches secret US spy satellite on 19th anniversary of company's 1st-ever liftoff (photos)