We’ve had some fantastic astronomical news this month. Last week, we encountered evidence of a “new ninth planet” lurking in the outer reaches of our solar system—170 years after the discovery of Neptune. And earlier in January, we heard a cacophony of whispers about minute gravitational waves being detected for the first time ever. Either one, if true, would be amazing to both astrophysicists and space lovers and would be the biggest discovery of 2016. We should be excited about them, but we should be careful about getting our hopes up so soon.
A New Planet, Far, Far Away?
A couple fellow science writers and I went hiking at Castle Rock State Park in the middle of the Santa Cruz Mountains yesterday, and along the trail, we encountered a variety of people. On our way down, we happened to overhear a conversation: “What’s your favorite planet?” followed by a reply, “Did you hear about the new planet scientists discovered?” Isn’t that great? I’m glad that the story got so much media attention and made it to the front pages of newspapers. It intrigued people, and they’re talking about it.
By studying the strangely aligned orbits of Kuiper Belt Objects far beyond Pluto’s realm, astronomers may have inferred evidence of a planet up to 10 times bigger than Earth. It would be much, much farther than Pluto, making it hard to spot. And from that distance, our sun would look almost like any other star. But if it exists, a new world (dubbed “Planet X”) joining our solar system’s family, even such an estranged cousin, would be exciting indeed.
Nevertheless, we should be concerned that the results are still very uncertain. The authors of the paper in Astronomical Journal, Konstantin Batygin and Mike Brown (both at Caltech), argue that there’s only a 0.007% chance, about one in 15,000, that the clustering of the distant objects’ orbits could be a coincidence. But it’s possible that the behavior of the orbits could have other possibly more likely explanations, such as other unseen Kuiper Belt Objects with orbits aligned in the opposite way. (Other astronomers, like Scott Sheppard and Greg Laughlin, estimate the chance of a planet really being out there at 60-70%. I wouldn’t bank on those odds.)
For that reason, we should remain skeptical for now. Some reporters and editors were a bit more careful than others. For example, while some headlines used appropriately hedging words like “suggest” and “may,” papers like the Denver Post and Washington Post had “The New No. 9” or “Welcome to Planet Nine.” This is already an exciting story to tell though, and we don’t need to exaggerate to get readers’ attention. If the planet turns out not to exist, people who read overblown headlines like those will be frustrated and confused.
Finally, we should all recall that Mike Brown was the main force behind Pluto’s demotion by the International Astronomical Union ten years ago. Since he calls himself the “Pluto Killer” (and wrote a book, “How I Killed Pluto and Why It Had It Coming”), it would be ironic if he helped discover a new ninth planet, replacing Pluto. But he and the Caltech news office seem to have hyped up his paper’s findings more than they deserved, given all the uncertainties involved.
Gravitational Waves Discovered?
While procrastinating and flipping through Twitter earlier this month, I came across some juicy gossip. I heard what sounded like the tantalizing detection of gravitational waves—an unprecedented achievement. These tiny ripples in space-time, predicted by Albert Einstein and thought to be produced by collisions of black holes or neutron stars, had been too small to measure before. Gravity is the weakest of forces, after all.
But it turns out that Lawrence Krauss, a well-known cosmologist and provocateur at Arizona State University, had caused the hullabaloo with some ill-advised tweets. He once again drew the media’s limelight to himself by spreading rumors that scientists in the Laser Interferometer Gravitational-Wave Observatory (LIGO) collaboration had detected gravitational waves for the first time. In the process, he put those scientists in a tough spot, as I’m sure they faced pressure to make sensitive statements about their ongoing research.
The LIGO team is still working on their analysis using a pair of detectors in Louisiana and Washington state, and they haven’t yet produced conclusive results. From what I can tell, they may have evidence but the situation is far from clear. There is nothing wrong with waiting a while until you’ve thoroughly investigated all the relevant issues and sources of error before announcing a momentous discovery. The alternative is to prematurely declare it, only to face the embarrassing possibility of retracting it later (which sort of happened to BICEP2 scientists with their supposed discovery of primordial gravitational waves).
Gravitational waves will have to remain elusive for now. And if and when LIGO physicists do have convincing evidence of gravitational waves, they need not share any of the glory or credit with Krauss.
Fortunately, in spite of this excitement, science writers and editors kept their cool and soberly pointed to Krauss’s rumors before digging into the fascinating and painstaking work LIGO scientists are doing. Here’s some excellent coverage by Clara Moskowitz in Scientific American and by Lisa Grossman in New Scientist.
[26 Jan. update: I decided to tone down my criticism of Mike Brown, but not of Lawrence Krauss.]
4 thoughts on “Exciting and Controversial Science: Gravitational Waves and a New Ninth Planet?”
One problem no one mentions about the “new Planet 9”: reviewed paper have been published (shortly after acceptance of the new definition of what planet is, forgot the Ref, do search…) proving that even on a closer orbit than the proposed “new Planet 9” even the body of the size of Jupiter … would not qualify to be a planet as it would not be able to “clean the neighborhood” as definition requires. Hence, without changing the definition yet again, we are stuck with 8 planets of Solar System forever. Would confirmation of “new planet 9” that could not be called a planet despite being of quite some size force re-evaluation of the definition? Hopefully.
Thanks for your reply. That’s a good question. You’re absolutely right, one of the IAU’s criteria for planet status is that the object must have cleared the neighborhood around its orbit. If this “Planet Nine” actually exists, I think it would be the most massive object out there and would have cleared its neighborhood and therefore would count as a planet. But it’s not convincing to me yet that there’s actually a planet there.
Now it’s official! LIGO scientists have detected gravitational waves!
Here’s the Physics Review Letters paper, published today:
and here’s some commentary on the impressive achievement:
Lawrence Krauss excepts your apology!