Oh man, Heathrow is not exactly the easiest of airports at the best of times, but landing an hour after the UK went to "critical" security status is not a good time. In the rain.
Oh, and I understand about the whole bus thing, that you don't want large vehicles driven up to the terminal right now - but someone needs to tell people when they do this. Lot of people queued up for a long time waiting, in the rain.
Much more cheerful than Athens though. Mustn't grumble, eh?
Ok, so from the comments at the Extreme Solar Systems conference, and here, I infer we will have some energetic "what is a planet" arguments between now and the Rio IAU assembly...
I'm a traditionalist - astronomical definitions are phenomenological and arbitary, therefore inconsistent.
The current IAU definition is inconsistent, and so are all the alternatives I heard.
What I dislike is any definition that changes what an object is depending on its history or environment - in particular, if we were to lose one of our planets, or the Sun were to die, I don't think the current planets should stop being planets just because of the change in circumstance.
Ah well, makes for fun discussions over beer or coffee.
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What do you mean by "lose one of our planets" here? Jupiter kicking Mars out, or what?
There has been several attempts at arriving conclusively at some kind of a definition for what constitutes a planet several times before from what I know. Like yourself, I'm not sure that cosmogony can at all be an effective criteria. I mean how are you going to ascertain for sure an object's true origin? i.e. How was it born (e.g. direct collapse, gravitational collapse or via accretion)? What if one day we are to find out that say Jupiter does not have a solid core as the models for accretion predict and thus could either have been a directly collapsed object (i.e. a formation ala the Sun), do we then strip Jupiter of its planetary status? An interesting piece on this debate can be found here http://astro.berkeley.edu/~basri/defineplanet/whatsaplanet.htm Some fascinating thoughts on the subject by Prof Basri. I do share many of his thoughts on the subject.
Re: Heathrow, I was flying from Gatwick to Chicago the weekend after the 7/7 bombings, and we weren't able to take *anything* on the plane--not even a book, newspaper or pen. It was a long, long flight...
But then, if you're even going to feel safe traveling, then right after a terrorist attack is probably the time you're going to do it. With the stepped up security and the perps lying low or on the run, not much is likely to happen to you.
That, and the fact that many others on the same plane had been stuck in London for two or three days, ensured that I didn't complain too much about the inconvenience--it could have been much worse.
Or you could try flying from Heathrow a few days after the liquids incident. I got to take a little plastic baggy with my passport and wallet. The laptop actually had to get checked. It was ensconced in bubble wrap and survived.
The good side was I got bumped up to business class. So, actually go United for treating me right...I think I had no right to grumble at all.
Yeah, I mean if the solar system were to become unstable - which we don't think it will in the next ~ 10 Gyrs, but it will eventually - then a planet will likely be ejected.
I don't think Mars stops being a planet just because Jupiter ejects it - as a matter of nomenclature.
Heathrow was actually surprisingly sane in the end - I showed up 4 hours early to check in, and security was very thorough but efficient and reasonably fast. Armed police out in force, with concrete barriers, most I've seen since the IRA bombings in the 90s.
Arriving was worse, because they had gone to maximum security but none of the arrivals knew. So, for example, about a 100 people at terminal 1 were waiting for buses behind the terminal, but they had closed the road round the corner and diverted the buses, but not told anyone. When someone finally came over and realised and told people, it was almost impossible to go anywhere - there were thousands of people lined up for taxis. I lucked out, I found my bus stuck in a traffic jam near the central bus station and the driver let me on when I waived (illegally so - but very cheerfully). Did I mention it was raining, and cold. It was lovely.
Interestingly, the hotel had door security and all bags were searched. Very thorougly.
That I haven't seen in Europe for a long time.
When the first IAU proposed planet definition was unveiled in Prague, it specified that a planet must circle a star (along with some other messiness). At the first meeting to discuss this definition, Frank Verbunt and I got in line to speak (we ended up being the first in each line to not get to speak), both with the same idea; that planets shouldn't stop being planets just by being ejected from a system.
Luckily the Prague IAU nomenclature group chose to pick its battles carefully, and avoided all issues outside our solar system with the next draft. I do wish the IAU would post proposed planet definitions a year before voting, so as to allow the whole community to think about it and make recommendations.
Go, free-floating planets!
Craig while you may have your point about continuing to call planets who are genuine cases of planets ejected from some planetary system planets or free floating planets (especially those with masses below the deuterium fusion limit i.e. ~13 MJup for solar metallicity), what about those free floating objects hovering near 13 MJup and whose Fe/H value may not be so easily measured? Do we call them free floating brown dwarfs or sub brown dwarfs or free floating superplanets? And could not objects of even terrestrial masses form directly out (then somehow get ejected via gravitational perturbation by other forming stellar embryos) of those same gas/dust molecular clouds that can collapse into stars and brown dwarfs? If such terrestrial planet like objects can collapse out of molecular clouds, should w also call them planets or what? Any ideas? Also what about those borderline cases like XO-3b? It seems that the traditional accretion model cannot produce objects as massive as XO-3b but at the same time it lies right at the deuterium fusion threshold, what then do we call objects like XO-3b? A planet? A brown dwarf? Or a sub brown dwarf?
If the final classification of objects like XO-3b is subject to its cosmogony, how then are we to determine one way or another (i.e. that it got to be what it is as a consequence of accretion or that it formed via gravitational instability or it is a directly collapsed object aka a star-like formation)?