Wednesday, July 15, 2015

Hello, Pluto!

Artist's rendition of New Horizons at Pluto. Credit: NASA
Unless you've been living under a rock for the past couple of days, then you likely know that NASA's New Horizons probe recently accomplished its primary mission: perform a flyby of Pluto to collect data and pictures to send back to scientists on Earth. It was the culmination of 9.5 years of travel to that far-off world (so far away that it takes light approximately 4.5 hours to cover the distance), though only the beginning for the scientists who will examine the data for years to come.

Interestingly, it will take nearly 16 months (yes - MONTHS!!!) for the full payload of data to make its way back to Earth. Why? Because, at best, New Horizons can only communicate at 4,000 bits per second (bps)...and, sometimes, as slow as 1,000 bps. "But this is NASA! My home cable modem is much, MUCH faster than that! What's their problem?!?" Physics...physics is their problem. Not only is New Horizons 4.5 light-hours away (and growing), but the transmitter on the craft only operates at 12 watts. It takes NASA's largest receivers here on Earth - the massive 70m dishes located at various locations around the globe - in order to discern the meager signal from the background noise. Let that percolate in your gray matter for a moment: 12 watts - approximately 1/5 the power of a typical 60 watt household light bulb - and it's billions of miles away! NASA can perform some comms 'gymnastics' to bump up the effective speed a bit, and Emily Lakdawalla does an excellent job of going into much greater detail than I could - it's definitely worth a read.

What next?
Now that New Horizons has had its Pluto encounter, is the mission now complete? Will it be left to drift aimlessly through the cosmos? No, not by a long shot. Firstly, it must now transmit all of the science data that it collected during the flyby. Secondly, scientists have the opportunity to direct New Horizons to visit another Kuiper Belt Object (KBO) - objects inhabiting the zone of the Solar System beyond Neptune's orbit.

Though the target has not yet been selected, the list has been narrowed to a handful of objects. No spacecraft has ever visited a KPO, and doing so presents an excellent scientific opportunity to observe something that may well indicate the make-up of the early Solar System. The limiting factor is neither fuel nor technology - it's funding. NASA needs continued funding to pay for the personnel to staff the operations center and for the resources required to maintain communications with the craft. I hope that our elected leaders see the huge return on the investment from this program and continue to fund it.

Is Pluto a planet now?
As far as I'm concerned, Pluto was *always* a planet...and continues to be so. In fact, though my position was originally borne by tradition, the more we learned about Pluto from New Horizons further convinced me that it's a planet. Unfortunately, I'm not the final arbiter in making that decision. I've spoken with some people that wholeheartedly feel that planetary status is something to be reserved for larger celestial bodies, and that Pluto fails to meet this criteria. Additionally, they argue there could potentially be hundreds more 'planets' in the Solar System if we use Pluto's characteristics as an entry-level baseline. Well, what of it? "The more, the merrier!", I say. To me, if an object is gravitationally spherical and doesn't directly orbit a non-stellar body, then it's a planet.

"Ah HA! Pluto and Charon orbit a shared center of mass, which is outside Pluto's body! See? Even by your definition, it isn't a planet!" Well, no...not at all. Notice that I said "doesn't directly orbit a non-stellar body." Empty space isn't a non-stellar body...it isn't a body at all...it's simply empty space. At worst, this would make Pluto and Charon a binary planetary system. Further bolstering Pluto's status as a planet is that it harbors an atmosphere. "Ahhhh! Well, Titan has an atmosphere, too! In fact, it's denser than Earth's atmosphere...but it's classified as a moon. So, is Titan now a planet?" Nope. It orbits Saturn.

Other criteria used to disqualify Pluto's inclusion in the 'Planetary Club' is that its orbit is wonky (yes - that's a highly scientific term. Trust me.). Not only is its orbital plane significantly tilted in comparison to the rest of the Solar System, but its orbit is very eccentric (meaning: it's far less 'round' than the others). Well, whoop-dee-do. So what? That has to be one of the lamest criteria being used to bump Pluto to 'dwarf' status.

Do I think Pluto will now be reclassified as a planet? Maybe...but probably not. The most likely outcome is that there will be a re-write of the entire classification system (rocky planets, gas planets, ice planets, dwarf planets, etc.) so that they're all technically planets...but are each grouped according to physical properties. Honestly, I'm not necessarily opposed to that. It'll be interesting to see how this plays out, especially as the data starts flowing in from New Horizons.

USA! USA! USA!
Wow! I admit that the display of national pride during the flyby brought a tear to my eye. While I have always harbored a love of our national scientific/exploration endeavors, that sort of display not often seen in today's 'politically correct' environment. My country might not do everything right...and, if we're being totally honest, it does quite a lot wrong...but which other nation has come close to our record of planetary exploration? American taxpayers, I don't think you know what a gem you have in NASA. Contact your elected leaders and encourage them to give NASA more than the pittance they currently receive. Imagine how much more NASA could do with extra funding.


Thanks for reading.