After spending roughly a week away from my press feed, I found myself face to face with a lot of intriguingly titled press releases. One announces: “Astronomers Find Largest Exoplanet to Date,” and another teases “Monster Galaxy Pileup Sighted,” and yet a third promotes “BLACK HOLES IN FEEDING FRENZY” (Yes, the press officer yelled in type). Other provocative titles employed the words: Largest, flood, giant, colossus and puff. While some of the stories lived up to the hype, in general the truth is far less interesting than the title. (image left, credit NASA / JPL-Caltech / K. Rines (CFA))
Case in point, let’s consider that “Largest Planet.” When I see the word largest, I tend to think high mass and high radius. This new world, discovered by an international team using the Trans-atlantic Exoplanet Survey (TrES) network of telescopes, is in fact lower in mass than Jupiter, but sports a radius 1.67 times larger than Jupiter’s. So, it is large in radius but well below average in mass. In fact, the paper could have just as easily been titled “Lowest density exoplanet found.” So, it’s exciting, but confused. And what’s more, as we get more data on other worlds we may find some of the other planets are actually larger in radius! With today’s technology we can only measure the radius of planets that transit their host star. This is a small part of the total population. With future missions, like Darwin or the Terrestrial Planet Finder, it will be possible to start to image planets directly, and we’ll be able to get better measurements of planetary radius.
So, at the end of the story, it was just another bloated hot Jupiter (admittedly way more bloated than normal). None the less, it made the news (I heard about it on NPR). If it bleeds it leads, and if its a planet its at least printed.
Turning away from the planet of false promises (it would have been so cool if it was the most massive – then I’d be able to compare it to the smallest brown dwarf and have a neat discussion on the boundary lands between planets and stars), I popped open the piece on a Black Hole feeding frenzy. I have to admit, my mental image of a feeding frenzy comes from National Geographic specials on sharks. When I read this headline I imagined gas and dust being messily gobbled with bits of material getting flung about even if most of the matter was getting consumed. As strange as this may sound, my mental image perfectly matches this scenario. It appears some galaxies periodically gravitationally suck in large clouds of gas and dust or small gas rich galaxies. When these systems get sucked in, they fall apart, with much of their mass falling into the galaxy’s central supermassive black hole. While feeding, the supermassive black hole lights up and becomes a quasar. As the material streams in, some of it’s torn off and ejected in a new direction, like the bits of fish flung in a aquatic feeding frenzy.
Astronomers had believed this was how quasars were fueled for a long time, but they’d had problems proving the consumed material came from outside the quasars. What is new in this work, done by Hai Fu and Alan Stockton of the University of Hawaii, was the discovery that the larger galaxy had lots of heavy atoms that had been produced in stars while the consumed gas was basically pure hydrogen and helium. This made it clear the consumed material had to have come from outside the galaxy – proof that the theorists got it right.
This leaves us with one more Monster tale. Using the Spitzer Space Telescope and WYIN telescope, astronomers Rose Finn (Siena College) and Alexey Vikhlinin (Harvard-Smithsonian CfA) discovered 4 giant galaxies – galaxies that have an average mass larger than out Milky Way – in the process of merging. All previously imaged mergers had either involved smaller galaxies or fewer galaxies, or most likely both fewer and smaller galaxies. If you are willing to go with the “A large truck is a monster truck,” then it’s not a stretch to say a large galaxy is a monster galaxy, and these monster galaxies are piling up in the center of this cluster.
So, at the end of the day, we have one misleading use of the word “large,” one good use of feeding frenzy, and one stretched analogy involving monsters. And, the authors sucked me into reading all their stories, one potentially abused word at a time.