Calculating Mass

[Sparky]

http://www.space.com/24026-alien-planet ... nique.html

This illustration shows HD 189733b, a huge gas giant that orbits very close to its host star HD 189733. The planet's atmosphere is scorching with a temperature of over 1000 degrees Celsius, and it rains glass, sideways, in howling 7000 kilometer-per-hour winds. Image released July 11, 2013.

Glass moving sideways would be a "deal killer" for habitation, wouldn't it?

To understand how this method works, imagine that an exoplanet's atmosphere gets thinner with altitude, just as Earth's does. This is because the strength of a planet's gravitational pull weakens the greater the distance from the planet.

Since the strength of a planet's gravitational pull depends on its mass, researchers can deduce an exoplanet's mass by seeing how the planet's atmosphere thins with altitude. This involves gazing at exoplanets as they pass in front of their stars and looking at starlight shining through the atmospheres of those worlds to determine the atmospheric pressure drops with altitude.

(A limitation of this approach is that it only works on planets with atmospheres, de Wit noted.)...

[viscount aero]

Whenever I see "space.com" I know I'm going to be reading a supermarket tabloid story akin to a Kardashian pregnancy or romance scandal.

This sounds like another "planet made of diamond/it rains diamonds on this planet" or "super massive black hole ejecting matter the size of the universe" kind of story. Scientists don't even understand what is happening in the atmospheres of our local gas planets. Yet they are certain that they know it rains glass sideways on a distant exoplanet

Notice, too, how they made the exoplanet look like Earth in the illustration concept. This allows the reader to subconsciously connect with and accept the article as fact.