NASA's Kepler telescope finds 5 new planets NASA's Kepler space telescope has already uncovered new astronomical oddities and five large planets in its first six weeks of searching for Earth-like bodies outside our solar system. Although the quintet revealed by Kepler are all much larger than Earth and far too hot to harbor any life known to science, NASA said the …
The patch of sky Kepler is looking at mostly contains stars which are a fair distance away (thousands of parsecs). Measuring the distances of stars that far away is difficult, the results usually have large error-bars. That's probably why the distances aren't mentioned - they're unknown to a precision worth quoting.
"Kepler 7b has about the same density as Styrofoam."
It's obviously new. I'm sure that whoever ordered it from Magrathea will get around to unpacking it soon and it'll become a perfectly normal, earth-type planet, briefly surrounded by huge chunks of styrofoam until the cleaners hoover up.
When they start measuring planets that are hotter than their host star or have an average density of less then that of expanded polystyrene, my immediate response would be to double check the instruments and the models they are using to calculate these values from the observations, as well as their assumptions about distance of host stars, etc.
The way the density is derived is fairly simple, it's basic geometry and Newtonian physics. The major uncertainty comes from estimating the size and mass of the host star, and typically it's less than about 10% in each of those - certainly well enough understood to know that these exceptional planet densities are highly unlikely to be due to errors. Put it this way - if these estimates are way off then we seriously misunderstand how our Earth orbits our Sun!
The parameters for our own solar system are fairly well known. For example, the size, distance from Earht and temperature of the Sun are known to a fairly decent precision.
When you start talking about distant objects, things like distance are calculated indirectly from such arcane things as red-shifts in the star's spectrum, which in turn tells us how fast it is moving from us, and from that, teh distance is estimated. Estimates of size are based upon brightness and distance, and models of how types of star other than our sun are supposed to work. Compound the errors in these various methods, and values become somewhat less determinate.
What I am suggesting is that if there is a flaw in any of the models used to calculate these things (for example a solar system is moving at a different speed to that expected for its distance, thus altering the red-shift), then the assumptions that have been made in the calculations of the star's distance, size and temperature are invalid.
"The size of planets can be estimated from measuring the size of the dip, and their temperatures by the type of star it orbits and the planet's orbital period."
How does temperature affect orbital period? Either this is a mistake or there's some really interesting and clever physics behind it. Either way, people should be told.
Paris because she knows all about bodies orbiting stars.
The orbital period (or more intuitively the distance from the star to the planet*) determines the planet temperature, not the other way round. Basically the closer they are to the star, the more energy they receive from it.
(*) orbital distance and orbital period are closely related through Keplers Laws.
Ah, that makes some sense. So the temperature is calculated, based on a steady state assumption, rather than measured. But that doesn't fit th statement below, which implies a measurement which doesn't match the theoretical calculation:
"For example, Kepler found celestial objects that are hotter than the host stars they orbit."
Paris because she knows all about hot bodies.
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