OK, the pictures are great and it’s nice to see NASA have successful mission, especially one that began 9 years ago, but what we really care about is whether our favorite former-planet-unfairly-downgraded-to-dwarf-planet has been measured accurately and taken its rightful oxymoronic place as the biggest dwarf. Well, the results are in and the answer is a resounding YES! Go Pluto!
The measurements taken by the New Horizons spacecraft and confirmed by New Horizons lead scientist Alan Stern show that Pluto’s diameter is 1,473 miles (2,370 km) while that brazen newcomer Eris is a mere 1,445 miles (2,326 km) in diameter. Eris is three times further from the sun than Pluto and 27% more dense. That density combined with the previous blurry images of Pluto (due to its atmosphere) temporarily put Eris at the top spot. With the new data sent back from the New Horizons swing-by, Pluto takes back the crown, said Stern.
That settles the debate about the largest object in the Kuiper Belt.
Alan Stern was one of the more vocal objectors to Pluto being declassified as a planet in 2006, just months after the New Horizons was launched. Pluto was downgraded because its mass is not large enough to have “cleared the neighborhood around its orbit.” Stern contends this means that Earth, Mars, Jupiter, and Neptune, all of which share their orbits with asteroids, should also be downgraded. Further, the loose definition could classify large bodies like the Moon as planets. Finally, the decision was made by a vote of only 5% of the world’s astronomers – a majority of whom Stern felt supported Pluto planethood.
Now that New Horizons has achieved such a phenomenal success, will lead scientist and unabashed Pluto fan Alan Stern – along with millions of other Pluto-for-planet people – see it be reclassified back to its rightful planetary status? Only time will tell.
In the meantime, let’s enjoy the pictures from this sensational mission.