Majestic relative of Earth found

The discovery of the most Earth-like planet found to date outside the Solar System was announced today[1]. At least five times the mass and 1.5 times the diameter of our home planet, the discovered exoplanet takes 13 days to complete a year around its mother star - the red dwarf Gliese 581. Most notably, however, the temperature of this planet is predicted to be in the range 0...40 degrees Celsius, opening up the possibility of there being liquid water on it!

Most of the more than 200 planets found so far around stars other than the Sun have had more in common with the gas giants (Jupiter, Saturn, Neptune, Uranus) than the rocky, or Earth-like planets (Mercury, Venus, Earth, Mars) of the Solar System. However, the hunt for other Earths is on and today's announcement certainly marks the most significant discovery so far on that quest, showing for a fact that planets quite similar to ours exist around other normal stars.

Red dwarfs, with masses and temperatures around and below half that of the Sun, are the most abundant type of stars in the Universe and most of the 150 billion or so stars in our Galaxy fall into this category. They radiate less energy than the Sun, which is why the newly discovered planet potentially has conditions similar to Earth even though it's eleven times closer to its mother star than the Earth-Sun distance. Most importantly, however - Gliese 581, at a distance of 20.5 light-years, is one of the closest neighbors of the Sun (the closest is Alpha Centauri at 4.4 light-years and the diameter of the Galaxy is ~100000 light-years). This goes to show how difficult it is to discover exoplanets around even the nearest stars, but also implies that red dwarfs further away from us are likely to harbor planets as well. And there are many, many red dwarfs out there.

As for this particular planet, it is not known yet whether it's tidally locked (always keeping the same side to its parent star, exactly like the Moon is tidally locked to the Earth and always keeps the same side visible to us), which is quite possible for a planet so close to its star and would have unknown consequences for its climate and habitability. Nothing certain is known about the atmosphere, if any, of this planet, nor the composition - but observational astronomers and engineers will be working hard to get at that information in the coming years - years, which will undoubtedly reveal a plethora of new planets to study and send our imaginations running wild.

PS. Wow! :)

References:
[1] "Astronomers Find First Earth-Like Planet in Habitable Zone", ESO Press Release, 2007.04.25

Did someone mention creationism?

Sweeping Statements, Simple Science

Update: paragraph 3 was clarified on 2007.04.27

Quite often scientists forget or ignore the fact that, being raised and fed by the rest of society, they can expect the public to remain supportive and understanding of their pursuits only if the scientists themselves make an effort to introduce their results and, on a more general level, explain how science works. This can not be done with fancy words and sweeping statements - an explanation proper has to be very carefully thought through and worded. I trust this line of thought is not new to our readers.

Scott Tremaine, the Princeton specialist on stellar and planetary dynamics, recently held a neat general-audience lecture in Leiden, in which he expressed his frustration at being quoted on a young-Earth creationist website in favor of the rubbish[1] presented on the site. Specifically, as an authority on planetary systems, he was quoted there as saying "most every prediction by theorists about planetary formation has been wrong"[2].

As Dr. Tremaine stated in Leiden, his quote sounds overly pessimistic of planet formation theory if taken out of context. One does not need a Masters degree in astrophysics to point out that while

• "planet formation is so complex that although a large number of participating subprocesses are understood very well, a fully self-consistent model of the entire process is currently out of reach" (this was kindly suggested by Dr Carsten Dominik as a more precise way of expressing the point, in the original post I put my foot in my mouth with "planet formation is messy and not easily analytically describable")
• the planetary systems so far found around other stars have turned many prior ideas of the birth and nature of these objects upside down,
  

there were and are general correct ideas about the planet-building process, e.g. that planets are born in disks of gas and dust around young stars. Also, the basic physics that governs collisions of dust grains - the building blocks of planets - has not changed, although the models that use it have. The main point: that such self-evident truths about planet formation did not fall under Dr. Tremaine's statement would have been obvious to a specialist. However, it was not presented to a closed circle of specialists at a meeting, but in Science Magazine for everyone to read.

This is a difficult situation. Should well-known scientists really watch their every word when engaging in communication with the public? Coming from someone as inexperienced as yours truly, this might sound naive, but I do believe they should do just that - enforce strict self-discipline in their choice of words, especially when simplifying situations or using analogies. Of course, everyone else - including students - should try their best to do the same.

Creationists and others who go about nibbling on the facade of science by way of ad hominem attacks and picking out carelessly worded thoughts from popular science texts, without entering the building to see what the facade attaches to, are all too happy to jump at phrases like "nobody knows what this is" - incidentally, the latter basic thought was caught in two public astronomy lectures by prominent scientists recently[3], in both cases a good alternative comment would have been "nobody knows what this is yet, but people are working on it and the pieces are falling into place, I'll give you the references if you're interested".

Certainly an explanation geared towards a general audience should be simple, and naturally time is always in short supply for a public lecturer. "Simple", however, does still not mean "as few words as possible".

Footnotes:
[1] Dr. Tremaine was not so explicit in voicing his judgment. Discussion on this classification of young-Earth creationist claims is welcome.
[2] See original quote in Science Magazine, http://www.sciencemag.org/cgi/reprint/295/5555/604b.pdf
[3] The talks: Oort Lecture in Leiden, 2007.04.18, by Dr. Scott Tremaine; Silicon Valley Astronomy Lecture, 2007.02.28, by Dr. Bruce Margon. The latter is available on iTunes as a podcast.

More than just poor style

“Weekly” is an English language paper with news of cultural and social activities in Amsterdam. This week’s “Weekly” has the following two-liner under the section “Festivals”, on page 22:

Poolse filmlente. A week-long festival of recent films from Poland, one of the more controversial new entries to the EU.

Granted, this is a free newsletter, possibly not written by professional journalists, but the political reference is more than just poor style, or even bad journalism, it’s downright offensive. The “controversy” around Poland’s joining the EU, even if it’s a fact, has nothing to do with announcing a film festival, and therefore I have to infer that either (1) whoever wrote this has a position regarding the controversy, and felt like surreptitiously stating it, or (2) the writer doesn’t really have a position, but thought the sentence looked too short and thus added a random parenthesis. Either way, it’s an irresponsible act. For, whether the writer likes it, doesn’t, or doesn’t have an opinion on it, Poland is indeed part of the EU, and by taking a position or even merely acknowledging an issue, out of a proper context that explains it, the writer is being disrespectful of the Polish people and, just as grave, of the ideology that’s behind the EU.

Naturally, I don’t mean to imply that disagreeing with particular EU entries and with countries’ internal policies or social and political situation is off-limits; in fact, I will very likely discuss here, sometime in the future, the problems and threats I see in the general political direction that some European countries seem to be taking. The point I’m making is that the absolute lack of context, discussion and motivation for this kind of statement turns what would potentially give rise to intelligent discussion into an offensive, random comment.

A final remark: someone told me I was overreacting, the statement wasn’t meant to offend, and “Weekly” is hardly a newspaper people would read to find intelligent information about current issues. This line of argumentation is, I think, very naïve. The kind of xenophobic rhetoric that a few years ago would have aroused the indignation of the whole society is now slowly beginning to be tolerated, and, though I’m willing to grant that there was no intended malice in the sentence quoted, I do think it’s everyone’s obligation to make sure they’re not feeding the monster. “Weekly” may well be just a cultural newsletter, but that doesn’t excuse it from the obligation to be responsible.

Masters in Amsterdam

This entry unleashes “Masters in Amsterdam”, by Mihkel Kama and Salvador Mascarenhas. In this age of random information, we’ll do our best to channel here and comment on bits that earn our attention and test our competences. We will address topics related to our respective research areas, as well as issues in science, society, politics and culture.

At the moment, we are Master’s students at the University of Amsterdam, the Netherlands — Salvador at the Institute for Logic, Language and Computation, and Mihkel at the Anton Pannekoek Institute of Astrophysics. We are citizens of the glorious republics of Portugal and Estonia, respectively, facts that may every now and then play a role in the topics we address.

We encourage everyone to share their thoughts in the comments section, kindly requesting that comments to a given post conform to its spirit and style. Relevant additions and corrections to our posts are of course more than appreciated.

It may well happen that our thoughts turn out to be so dull as to disappoint our readers and embarrass our friends, but at least rest assured we will never post pictures of our cats or publish essays on the meaninglessness of life.

Mihkel and Salvador