Stars are mostly made of hydrogen and helium, and it's safe to assume that the largest planets would have a similar composition. The sun is made of about 75 percent hydrogen and 24 percent helium, the other 1 percent being heavier elements. Jupiter is roughly 71 percent hydrogen, 24 percent helium, and 5 percent other. So let's figure any large planet is three parts hydrogen to one part helium.
As long as there's no fusion going on, a large planet will be in a state of hydrostatic equilibrium. That means the weight of all that gas trying to collapse on itself is balanced by the pressure of the gas not wanting to be squeezed. The more mass you have, the more the interior is squeezed, and the hotter it gets. With enough mass, the interior gets hot enough for hydrogen to start fusing into helium. That critical mass is about 80 Jupiters.
This may worth something:
NASA's TESS helps astronomers study red-giant stars, examine a too-close planet | EurekAlert!
IMAGE: The NASA TESS mission is surveying the sky one sector at a time as it searches for planets. Here's the spacecraft's 13-sector mosaic of the southern sky, recorded over the... view more
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AMES, Iowa - NASA's planet-hunting TESS Mission keeps giving astronomers new realities to examine and explain.
Case in point: astronomers using the tools of asteroseismology - the observations and measurements of a star's oscillations, or starquakes, that appear as changes in brightness - have learned more about two stars bright enough to be visible in a dark sky to the naked eye. These red-giant stars - older, "retired" stars no longer burning hydrogen in their cores - are known as HD 212771 and HD 203949.
Opinion | What if All That Flying Is Good for the Planet? - The New York Times
With the holiday season fast approaching, many climate-conscious people may be wondering: Is my planned vacation for the other side of the world ethically indefensible? But let's try another question: If we really did all stop flying, would that save the planet?
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At the same time, aviation accounts for approximately 2.5 percent of human-induced C0₂ emissions. By contrast, deforestation, according to some estimates, contributes nearly 20 percent , about as much as all forms of transportation combined. If we want to truly take a clean sweep at reducing global greenhouse gases, then we must stop clear-cutting the world's forests.
Dance of the evening planets | News, Sports, Jobs - Adirondack Daily Enterprise
The southwestern sky seen from Tupper Lake at 5 p.m. on Nov. 19 showing Venus, Jupiter and Saturn. Venus will rise past Jupiter (on Nov. 23) and Saturn (on Dec. 10) and their positions on these days are shown, though they will be closer to the horizon than shown here. The waxing crescent moon will appear close to Venus on Nov. 28 and Saturn on Nov. 29. (Provided image)
After adorning the evening skies for most of this year, Jupiter and Saturn are moving toward the sunset horizon. In fact, Earth, in its faster orbit, is leaving them on the far side of the sun.
Not to change the topic here:
A rocky planet in this weird star system would have stunning skies | Astronomy.com
Over the past couple of decades, astronomers have discovered thousands of alien planets and solar systems. These worlds come in a wide variety of arrangements, many of which are quite different from what we see in our own solar system.
Some have giant planets that swing through the planetary systems in stretched-out, or “eccentric,” elliptical orbits, unlike the nearly circular orbits of planets like Jupiter and Saturn.
People can vote to name a new planet! - CBBC Newsround
It's part of a competition by the International Astronomical Union to celebrate its 100th anniversary.
Last month, hundreds of UK schools submitted ideas for the planet name, which have now been cut down to a top ten list by a team of astronomy experts.
All of the planets in our solar system orbit around the Sun. Planets that orbit around other stars are called exoplanets.
NASA video: 'Frankenstein' planet with 'extreme gravity' and 'hot
In a blog post to celebrate Halloween, NASA wrote: “A hulking monster of a star is stealing pieces of its nearby planet, WASP-12b, to assemble itself into the ultimate Frankenstein creation.
“The extreme gravity is stretching the hot gas giant into the shape of an egg, all the while slowly cannibalising the planet.
“Relatively soon (10 million years – a fleeting moment in space-time) this planet will be completely devoured by its hungry star.
Star Wars Jedi: Fallen Order - List of All Planets - Attack of the Fanboy
You can’t have a proper Star Wars game without exotic planets to explore, and Star Wars Jedi: Fallen Order delivers on this promise. The question some of you have asked, though, is how many planets are there exactly? Well, warning: there will be spoilers below, so for those of you who enjoy discovering what the game has on offer on your own I recommend turning back now. I dunno, maybe read our review or other guides, but if you don’t mind being spoiled then press on.
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