Happy Birthday Pluto! 🛰

Happy 90th Birthday Pluto! Hope you’re having a lovely time in the Kuiper belt! ✨

It was 90 years ago on this date that the world learned there was a ninth major planet in our solar system, discovered by Clyde Tombaugh, a 23-year-old researcher at Lowell Observatory in Flagstaff, Arizona. But in 2006, following the recent discovery of many more Pluto-sized bodies orbiting in the same region of our solar system, the International Astronomical Union (IAU) decided to reconsider the way “Major Planets” are defined, and Pluto was reclassified to now belong to a new designation, the “Dwarf Planets”.

Note that a similar reassessment was made back in the 1850s following the discovery of Ceres in 1801, which was the first-known ninth planet to be discovered in our solar system. But within a few years, many other planets had been subsequently discovered all orbiting in the same region between Mars and Jupiter. And so it was decided that Ceres and all these other planets would be given a new designation: they are now all called “Asteroids” or Minor Planets.  — Today Ceres also meets the criteria and therefore is also classified as being a dwarf planet for the same reason that Pluto is. Ceres is the first dominant object to be discovered orbiting in the Asteroid Belt; and Pluto is the first dominant object to be discovered orbiting in the Kuiper Belt.

To learn more about Pluto, have a look at the following: https://www.sciencemag.org/news/2017/02/birthday-pluto-s-discovery-science-takes-look-back-dwarf-planet-s-long-strange-history

And to learn more about Ceres, have a look at: https://solarsystem.nasa.gov/planets/dwarf-planets/ceres/overview/

-DDO Defenders 🙂

After Apollo

Hi Everyone,

Fifty years ago, humanity made the first successful attempt to personally visit another celestial body. But since then, we have ventured no further than near-Earth orbit, one thousand times closer than going to the Moon. So when WILL humanity finally follow up on its first step towards being a truly space-faring species? Join us as we explore this and other questions on Saturday, July 6th at the David Dunlap Observatory.

July 6th 9:00pm – 11:30pm 

July 6th 10:00pm -12:30am

Hope to see you there!

-DDO Defenders 😊

An Evening With Astronaut Dr. Dave Williams

Hello All,

This Friday we will have a special guest speaker at DDO’s astronomy family night!

An Evening With Astronaut Dr. Dave Williams, Friday June 7, 2019, 9pm – Presentation and Book Signing

We are pleased to welcome Canadian astronaut Dr. Dave Williams, Canada’s spacewalking record holder, to the David Dunlap Observatory (DDO) to talk about his personal experiences as an astronaut, aquanaut and former director of Space and Life Sciences at NASA.  He is the author of “Defying Limits: Lessons from the Edge of the Universe” — an inspirational, uplifting, and life-affirming memoir about passion, resilience and living to the fullest.  And for members of the younger audience, he has collaborated with co-author Loredana Cunti on a series of exciting children’s books. Dr. Dave will be available for book signing after his presentation. Copies of his books will be available for purchase during the evening.

Hope to see you there!

-DDO Defenders 🙂

Hello Everyone!

This section of our site is currently under construction. We’re grateful for your patience during this time. More content coming soon!

-DDO Denfenders 🙂