One thing this implies is that the escape velocity of such objects increases linearly with mass, so the surface temperature they can sustain without losing mass increases quadratically with their mass. Massive super-jovian planets can orbit close to their star, limited only by tidal disruption. Some could even orbit within the outer envelope of the star for quite some time.

If a brown dwarf is right on the edge of stardom would it start protium fusion in only the part of itself that is the right pressure and then slowly burn out or would that ignition precipitate a pressure wave through the entire body forcing fusion to begin everywhere?

I kind of assumed the artist’s impression was working with perspective? The images shown in the sidebar seem to picture them at different relative sizes.

Nice charts in this paper that support this thesis

https://pmc.ncbi.nlm.nih.gov/articles/PMC6525489/

NASA exoplanet catalog has a neat system/star view

* https://science.nasa.gov/exoplanet-catalog/cd-35-2722-b/

> It is estimated that Jupiter is essentially the largest any gas giant can get

That does not appear to be the case if we mean mass, not diameter.

https://en.wikipedia.org/wiki/Super-Jupiter

https://en.wikipedia.org/wiki/CoRoT-3b

At some point I did some research and the Atacama was suggested to me as the best vantage point on earth for simple skygazing. Definitely on my bucket list.

I thought we’re supposed to call them dwarf planets now. Dwarf star, dwarf planet.

Planet++

I believe such organisations tend to do such things very intentionally :-)

About ESO [1]

> We are an intergovernmental organisation established in 1962 supported by 16 Member States (Austria, Belgium, Czechia, Denmark, Finland, France, Germany, Ireland, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom), our host country Chile and strategic partners.

So Chile has a distinct status, hence the margin...?

[1]: https://www.eso.org/public/about-eso/

The flags have also all (except for Finland, which appears slightly wider?) been squeezed into a uniform 3:2 aspect ratio; some of them (e.g. Belgium, Switzerland, United Kingdom) properly ought to have different proportions. I understand they can look more aesthetically pleasing when they’re all the same size, but it’s another little detail to notice. :-)

Now I can't unsee it :/

We don't really have that nomenclature. We just recently decided what a planet it for the solar system, and even that is contentious.

The idea of a black dwarf is also pretty wild. The universe isn't old enough for any black dwarves to exist yet, but eventually the brown ones will radiate enough heat away that they're no longer held up by the vibrational energy of the atoms they contain. They'll stop being fluffy and settle into a mode where they're held up only by electron degeneracy pressure (a.k.a the Pauli exclusion principle)... it's a bit like how neutron stars are stable because they're not so massive that they collapse to a black hole. Black dwarves will be stable because they're not so massive that they collapse to a neutron star.

What will this substance look like? Will it ring like a bell if struck? What color will it be? Will it conduct electricity? If so, how? Are the atomic nuclei now the charge carriers because the electrons are stuck? It would likely be a super-thermal-conductor, does that have any analogous properties to a super-electrical-conductor? Which of these can we observe without the sensor collapsing to degenerate matter itself?

I hope there's life around to conduct these experiments when they become possible.

The far side of the moon is no more or less dark than the side we see.

https://en.wikipedia.org/wiki/Subsatellite:

“A subsatellite, also known as a submoon, moonlet or informally a moonmoon, is a "moon of a moon" or a hypothetical natural satellite that orbits the moon of a planet”

I had to look it up and it is theoretically possible, they could be called sub moons or moonmoon. I'm partial to the name moonmoon personally.

The definition of a brown dwarf is that there is enough heat and compression for deuterium and/or lithium fusion, but not protium fusion.

The exact model limit is unclear, but the physics modelling is relatively straightforward.

First paragraph:

> The star is being orbited by a brown dwarf, an object too massive to be a planet but too small to be a star.

>According to the IAU working definition (from August 2018) an exoplanet can orbit a brown dwarf. It requires a mass below 13 MJ and a mass ratio of M/Mcentral<2/(25+√{621}), or roughly 1/25. This means that an object with a mass up to 3.2 MJ around a brown dwarf with a mass of 80 MJ is considered a planet. It also means that an object with a mass up to 0.52 MJ around a brown dwarf with a mass of 13 MJ is considered a planet

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There are three clear benefits.

1. Answering where humans come from is probably one of the the oldest question we have had. All religions try to answer this in one way or the other. I say, trying to come up with scientific answers is extremely valuable.

2. We feel awe at the wonders of nature, not much different from the awe that we feel when we see great human art. Tax dollars as well as charity are used to subsidize art often. This is similar, though there is more money involved here.

3. The problems one sees in different domains are always different. Funding agencies give money to the "directly economically useless domains" because the workforce that is trained and technology that is developed can then be applied to the "directly economically useful domains". The support money to the former is much smaller than the support money to the latter, but just enough to inject fresh ideas and creativity to the latter.

Digital cameras for humanity as a whole, and satellite based telescopes for maintaining US dominance for the last 50 years and the long peace. Knowledge is power.

Before the late 70s satellites used film that was dropped back from orbit to the ground and developed to identify Cold War troop movements.

No, but let's keep pouring billions into confirming that the laws of physics apply outside of our solar system - smaller objects orbiting larger ones? Who could have guessed?

I'm sympathetic to space colonization, which seems like the most optimistic long term future for humanity, but the focus on exoplanets, -moons, even signs of exo-civilizations feels like making up theories about the bottom of the ocean centuries before the invention of submarines.

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