A “hot Jupiter's” dark side is revealed in detail for first time | Hacker News Reader

A “hot Jupiter's” dark side is revealed in detail for first time

news.mit.edu

63 pointsWalterSobchak12 comments

This is a study of an exoplanet. Apparently, a "hot Jupiter" is shorthand for a general classification of planet type.

The planet at the center of the new study, which appears today in Nature Astronomy, is WASP-121b, a massive gas giant nearly twice the size of Jupiter. The planet is an ultrahot Jupiter and was discovered in 2015 orbiting a star about 850 light years from Earth.

Yes a large gas giant but right in close to the star.

There is a bias for finding them since they orbit rapidly (like our planet Mercury) but block much more light and we do good with noticing blinky lights

The comparison to Mercury's orbit is mildly inapt. A hot Jupiter is much closer to its host star than Mercury and subsequently orbits in a matter of a handful of days rather than Mercury's ~3 months.

There was a diagram of the solar system recently shared (like in the last few months) that really threw of my image of how close Mercury is to the Sun, especially relative to the Sun's size. Thanks to badly scaled diagrams, I'd always envisioned Mercury's distance to the Sun as being less than 2 solar radii (so a daytime sky would be pretty much all Sun). It's always a little surprising to realize just how much space there is in space.

Similarly, to scale depictions of the distance/size of the Earth and the moon were quite surprising to me too.

I feel like this was an appropriate example of Wittgenstein’s ladder

iron cloud and titanium rain - can't wrap me head around that.

That's what got me too! At first I was picturing a solid piece of iron, floating in the sky, but I'm assuming it's more like a cloud here on earth, except formed by iron vapor instead of water vapor.

Iron vapour, Titanium in liquid state. The amount of Energy required for that kind of state of matter would be huge. If only we could harness it somehow.

Like a sunlit fog at just the right angle to be blinding white. Only, it's midnight and that's a cloud of white hot liquid metal.

Why would a gaseous planet be tidally locked? Obviously a non-homogeneous solid object would settle with it's denser end "downward" toward the star, but I don't see how a gaseous planet would do so.

> 10 times fainter

What does that mean?

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