Category: comets

Starts With A Bang #38 — Interstellar Interloper `Oumuamua

The first identified visitor from another solar system gets its own Starts With A Bang podcast!

In 2017, the incredible happened: for the first time in history, we were able to identify an object passing through our Solar System that originated from outside of it! Interstellar interloper ‘Oumuamua was originally designated as a comet, then as an asteroid, and then as a new class of object: one of interstellar origin. It’s a fascinating object that’s the first of its kind, and much has been said about its composition, properties, and possible nature.

But, unfortunately, the most famous of those “nature” discussions was from Schmuel Baily and Avi Loeb of Harvard, claiming that it could be due to aliens.

Is that plausible? Is that even science? My guest for this edition is astrophysicist Paul Matt Sutter, author of the new book Your Place In The Universe, and we have an almost-hour-long discussion that goes to some fantastic and unexpected places. You won’t want to miss it!

The Starts With A Bang Podcast is made possible through the donations of our Patreon supporters, who get it early, get shout-outs, and much more!

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Book: Your Place In The Universe

In Science, And In Life, ‘Once A Failure’ Does Not Mean ‘Always A Failure’

“Adams initial failure to calculate and find Neptune did not prevent him from having later success with the Moon’s orbital motion. It in no way inhibited him in his greatest achievement: identifying the source of meteor showers, and confirming that Comet Tempel-Tuttle causes the Leonids. Similarly, Le Verrier’s immediate success in predicting the existence of Neptune didn’t lead to future success; his prediction of the existence of Vulcan, a proposed planet interior to Mercury to explain its orbit, failed to materialize.

In science, making a successful advance not only requires skill, talent, and persistence, but also a fair bit of luck. You can make mistakes along the way, in theory, in practice, and in judgment, but every new problem you tackle is a new chance to get it right. Treat your failures for what they are: momentary setbacks. In no way do they define your destiny.”

We all have our heroes, whether in sports, politics, war, art, music, or science. We like our heroes flawless: always right and victorious, never mistaken or beset by failure. But real life isn’t usually so clean. In fact, some of science’s greatest achievements were made by people who had colossal failures early in their careers. Perhaps no one exemplifies this more than John Couch Adams, who spectacularly failed to discover the planet Neptune in the mid-1840s, getting scooped by Urbain Le Verrier and his correspondents, led by the observers Galle and d’Arrest. Adams never blamed his corresponding observers, Airy and Challis, for their errors in judgment, and went on to solve one of astronomy’s greatest open problems: the origin of meteor showers.

Come get the incredible success-after-a-failure story of John Couch Adams, who should be known for much more than his failure to discover Neptune!

Ask Ethan: Why don’t comets orbit the same way planets do?

“Why [do] comets orbit the Sun in a parabolic path, unlike planets which orbit in an elliptical one? Where do comets get the energy to travel such a long distance, from the Oort cloud to the Sun & back? Also, how could interstellar comets/asteroids come out of their parent star [system] and visit other ones?”

When we see comets in our Solar System, they can be either periodic, passing near the Sun and then extending very far away, to return many years later, or they could be a one-shot deal. But comets are driven by the same gravitational laws that drive the planets, which simply make fast-moving, nearly-circular ellipses around the Sun. So what makes these orbits so different, particularly if they’re obeying the same laws? Believe it or not, most of the would-be comets out there are moving in exactly the same nearly-circular paths, only they’re far more tenuously held by the Sun. Gravitational interactions might make small changes in their orbits, but if you’re already moving very slowly, a small change can have a very big effect!

Why don’t comets orbit the same way as the planets? Find out on this edition of Ask Ethan!