The Pluto Story

Yep.. we’re jumping on the bandwagon and adding more to the Pluto pot today.. did you really expect anything less? Facts that we’re discovering, facts about the mission, and information all about what we’re doing out there, why we went there and so much more!

Is Pluto a planet? A dwarf planet?

Pluto is a dwarf planet, a Trans-Neptunian object, a Kuiper Belt object, and many other names. None of these are strictly “Planet” because the definition of a planet varies. The question of “What is a planet” is three fold. The object must orbit around the Sun, The object must be rounded by its own gravity, and it must have cleared its orbital path of debris. Pluto does two of these three things, since its neighborhood is the Kuiper Belt, it has not cleared its path of debris. There’s potentially millions of “Trans-Neptunian Objects” in the Kuiper Belt, and because of that, Pluto was classified as a Dwarf Planet. In the event that it suddenly clears its path, and survives, the IAU may promote it once again, but that’ll be in a few billion years.

Are we landing on Pluto? Why? Why not?

The short answer is, No. The reason is because our Solar System is far too big. One of my favourite quotes from Vlad the Astrophysicist, a friend of Peter Mulvey, “Space is too large, Time is too short”. Remember, Pluto is almost 9.65 BILLION kilometers from Earth, whereas Earth is only 93 million kilometers. Since the human brain has difficulty rationalizing such large numbers, think of it this way: A million seconds is about 11.5 days. A billion seconds is about 31.75 years. A trillion seconds is just under 32 centuries! The reason why we’re not orbiting Pluto is because in order to get to Pluto within a decent time, we needed to make it very lightweight, and launch it at very high speed (almost 14 km/s). The weight of the probe would’ve been significantly heavier to account for weight of fuel to slow the probe down and insert it into orbit.

What do we know about Pluto thanks to New Horizons?

Pluto is almost double the diameter we originally thought, at 2370 km! It was previously thought to be only 1151 km. This size now makes Pluto the largest known Kuiper Belt object (Trans-Neptunian Object). We know that it has an atmosphere – a thin one, but it’s something. We don’t yet know exactly what it’s made of, but we have guesses. Due to the increase in mass and measurements, we know it’s less dense than previously thought – this means that there’s more ice than previously thought. Here’s an approximation of the relative size of Earth and Pluto, and Pluto’s largest moon, Charon.


What does Pluto look like?

Previously, the best images we had of Pluto was this: (Taken by Hubble)


We now know it looks like this: (REAL COLOUR!!)


And here, just for S&G’s, is an artist’s conception of Pluto (I found this on Google images, so if this is yours and you want credit, leave a comment below and I’ll happily do so!)


So what happens afterwards? Is New Horizons coming back? Why? Why not?

 New Horizons left Earth and will never come back. The same reasoning behind why we’re not orbiting Pluto (weight, time, etc.), is the same reasoning behind why it will never come back. We would’ve needed to put much more additional fuel to slow it right down to a stop and then send it back to us. We’d also need to plot a course (TO THE QO’NOS SYSTEM, WARP 9, ENGAGE!!).. uhh.. sorry.. force of habit.. We’d also need to plot a course back to Earth, and have even more fuel to slow it down once it got here so we could scoop it up. It’s just not feasible. New Horizons has other missions planned after it’s out of range of Pluto, and that’s to go check out other TNO’s in the Kuiper Belt. Nothing is officially planned, only strongly suggested. I will post another article on my site once official announcements are made. The New Horizons mission will be officially over, assuming no mission extensions are granted, in 2026. At that time, it will be approximately 100 AU from the Sun (just under 15 billion kilometers).

Jeff Wilton

Jeff is the founder and owner of Everyday Science Stuff. ESS is a one man operation, with the core belief that all education should be served without crippling debt tuition, without revenue generating ads and without any restrictions of any kind such as paywalls, forced login and account creations, geographical restrictions, and so on.

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