#aka a brown dwarf or failed star | Explore Tumblr Posts and Blogs

spyglassrealms · 2 years

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Well I've done it again. The free Spelljammer demo adventure was released last week and promptly disappointed me because WotC didn't take the opportunity to make Realmspace more interesting (instead almost literally copy-and-pasting the original AD&D canon)... so I fixed it my damn self. Behold my insanity. I hope to god tumblr doesn't scromble the image quality. So tumblr scrombled the image quality, just look at it here instead.

First up, the sun. Named it Solis to differentiate it. Twin of our IRL sun; G2V yellow-white star. Big ol self-perpetuating nuclear explosion. Probably radiates magic too. Nobody lives there, it's the SUN.

1. Phomus: small airless metallic planet; probably a failed planetary core. Tidally locked to the sun; scorching hot on one side and frigid on the other. No endemic life; but the dwarves and kobolds adore the place and squabble over it endlessly.

2. Anadia: canon planet, retooled. Basically Mercury with an atmosphere. 3:2 spin-orbit resonance, so days are longer than a year here. Only habitable place is the poles, where there's abundant water. Halfling clans have set up dozens of domed arcologies in polar craters.

3. Coliar: canon planet; retooled. Small ice giant (like Uranus) with a quirk- its gravity, density, and warmth mean that life thrives here on countless islands floating in the air. Has 3 moons: Cyrretal, a jungle world; Voturna, an ocean world; and Aureline, a tundra world.

4. Toril: canon planet, untouched. Toril (or Abeir-Toril, if you like) is an Earthlike planet with one moon, Selune, and a cluster of asteroids floating in Selune's L5 Lagrange gravitational keyhole.

5. Karpri-Chandos: canon planets, retooled. Both ocean worlds with no seabed; only an ice mantle. Life thrives here, especially merfolk and fishfolk. Karpri and Chandos are basically twins so I made them a binary pair. Pair has two small airless icy moons: Synos and Andos.

The Garden, aka the Garden Belt: canon-ish. An asteroid belt overgrown with magic space trees. At its heart is Garden proper; a cluster of asteroids held together by an enormous space tree with an internal ecology. H'Catha, a (canon) discworld made by Beholders, is also here.

6. Almeron: small brown dwarf substar. So big that it fuses deuterium at its core, Almeron radiates a moderate level of heat and so has its own habitable zone. Has two small ice giants in its leading and trailing Lagrange points: Palocyne and Oranus. Also has 7 moons, almost like a mini solar system in themselves: Tavati is a volcanic world; Sidar is a warm desert world; Phylora is a warm forest world; Wylenir is a temperate Earthlike world; Merinal is a temperate ocean world; Airelyx is a cool ocean world; and Khysethris is a tundra world.

7. Sybil: small-ish ringed gas giant. Its air isn't breathable but folks go in to mine the gas anyways. Has 4 moons: Mingabwe, Nyralwe, and Lumenwe are small airless ice moons; Glyth (canon planet) is a cold Titan-like world with its own rings that has been claimed by illithids.

8. Ziris: large ice giant. Despite the freezing cold, toxic air, and high gravity, it still attracts gas miners... and kindori hunters. Has 2 moons: Kunain, a small airless rocky moon; and Thrinain, a small airless icy moon. These serve as spelljamming ports for space whalers!

9. Dunbaran: large icy world with thin air and rings. Frigid, silent, desolate- it is a relic of the system's chaotic formation. A network of tunnels below its surface holds eons-old secrets. Has 1 moon: Nuldor, a captured comet with something buried at its core.

The Shell: the outer comet cloud of the system, full of drifting iceballs, a handful of spelljamming ports, and flotsam from the astral sea.

If I may be sanctimonious for a moment- this is all facultative of what I felt was missing from SJ. Don't you want to dance a gravitational ballet among twelve shining moons over a violet sky? Don't you want to sail through the eye of a storm the size of your whole homeworld? Don't you want to watch the sun crest a crater rim, painting sharp shadows across a landscape of ancient cosmic violence? Don't you want to witness the glittering silent splendor of a glacial cliff, two billion miles from a sun, with your breath the only company in your helmet as you ponder how many eons your footprints will last?

Where's the cosmic awe? Where's the wonder?

THAT is what I want to bring to Spelljammer. The beauty in solitude and desolation and vastness. The wonder. The kinship of we who sail the endless deep is born of knowing that, out there, we are all alone together; and in a vast and awesome universe, all we have is each other.

#spyglass’ realms #the midnight sea #worldbuilding #tabletop stuff #please don't mind the organizing tags here #spelljammer #dnd homebrew #dnd #dnd5e #d&d homebrew #d&d #d&d 5e #dungeons and dragons #space art #ttrpg art

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skippyv20 · 5 years

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Cool! Thank you😊❤️❤️❤️❤️

Oddest stars we have discovered

The Egg-shaped star

Enter Vega (aka Alpha Lyrae or Alpha Lyr), an egg-shaped star located 25 light-years away from us. It is one of the most popular stars out there, and astronomers seem to study it more than they do our own Sun. Vega has a weird shape because of its superfast rotational speed, which is 93 percent of its critical velocity (aka “critical rotation,” the maximum rotational speed when the star would break apart). Vega is so fast that it completes one rotation on its axis in just 12.5 hours. Our Sun completes the same in 27 days.

This has left Vega bulging 23 percent wider at its equator than at its poles. The abnormal shape has transferred so much energy away from the equator that it is 2,200 degrees Celsius (4,000 °F) cooler than the poles.

Two massive stars merging into one

Over a decade ago, astronomers discovered a massive star in the Camelopardalis (“Giraffe“) constellation 13,000 light-years from Earth. They called the system MY Camelopardalis. Originally, amateurs had thought they were seeing a single massive star. But astronomers soon realised that they were looking at two massive stars closely orbiting each other. In fact, the partners complete orbits around each other in just 1.2 days.

The bigger star has a mass 38 times that of the Sun, while the smaller one has a mass 32 times that of our Sun. Astronomers later realised that the partners are going to slam into each other someday and create a ginormous stellar beast with a mass 60 times that of the Sun. In fact, the atmospheres of the stars are already interacting. This will continue until the stellar cores finally fuse into one. Astronomers do not know precisely what will happen at that time. However, they speculate that the merger will create a large explosion that releases massive energy.

The star with spiral arms

When we think of spiral arms, we envision galaxies like the Milky Way. However, star SAO 206462 is here to prove us wrong because it has two spiral arms. SAO 206462 is in the Lupus (“Wolf”) constellation about 460 light-years away from Earth. The star is surrounded by a very wide circumstellar disk made of dust and gas.

This broad disk is almost two times the width of Pluto’s orbit. Astronomers know that spiral arms can develop around a star when new planets are materialising inside its disk. In fact, they think that the two spiral arms were formed by two new planets developing inside the disk.

The star with water clouds

We know that stars are insanely hot. For example, our Sun averages around 5,500 degrees Celsius (10,000 °F) in the photosphere. However, how about a star that is just 100 degrees Celsius (212 °F)? That is the boiling point of water, which is too cold for a star. But that is the temperature of CFBDSIR 1458+10B . It is a brown dwarf 75 light-years away from Earth in the CFBDSIR 1458+10 binary system. A binary system has two stars that orbit each other.

The mass of a brown dwarf falls between that of a giant planet and a small star. It is too big to be called a planet but too weak to be considered a real star. Brown dwarfs are considered failed stars because they do not have enough mass for gravity to cause nuclear fusion, which is how stars produce light and heat.

Even at that, CFBDSIR 1458+10B is too cold for a brown dwarf. The temperatures of most known brown dwarfs are often between 177–327 degrees Celsius (350–620 °F), which is still considerably hotter than CFBDSIR 1458+10B’s 100 degrees Celsius (212 °F). Astronomers believe that conditions on CFBDSIR 1458+10B are more like those of a large planet than those of a regular brown dwarf. They even think that this cold brown dwarf may have clouds that contain water.

The star that became a diamond planet

Astronomers discovered the star-turned-planet when they received some pulsar signals in our Milky Way. Pulsar signals are radio waves and radiation released by fast-rotating neutron stars, which are the collapsed cores of dead giant stars. Astronomers discovered something was amiss when they found that the spin of the pulsar appeared to be affected by gravity. This type of spin could only happen if an exoplanet was orbiting the pulsar.

In fact, astronomers detected an exoplanet rapidly orbiting the pulsar at close range. The exoplanet also had a very large mass (like that of Jupiter) even though it was only five times bigger than Earth. At first, this didn’t make sense. An exoplanet orbiting that close to a high-gravity star shouldn’t have such a large mass that was so tightly packed. Astronomers soon discovered that the exoplanet had once been a star that was part of a binary system. The pulsar had been the second star, and the two had orbited each other in those days. However, the stars eventually burned through their fuel and got so close that the bigger one yanked the matter from the smaller star.

The result was a cold planet that orbits a pulsar. However, there is beauty in the destruction. Astronomers believe that the fusion-less planet is comprised of crystalline carbon, the same material that makes up diamonds.

The star within a star

A Thorne-Zytkow object (TZO) refers to a star that is inside another star. The object was named after physicist Kip Thorne and astronomer Anna Zytkow. Together, they proposed the existence of such a star in 1975. Thorne and Zytkow said that TZOs are formed when a neutron star gets consumed by a red supergiant star.

As previously mentioned, a neutron star is the collapsed core of a dead giant star. A red supergiant is an old star that is almost out of hydrogen—a major element it needs to create light and heat. Red supergiants are the largest stars in the universe and can reach up to 2,000 times the size (in diameter) of our Sun.

In 2014, astronomers believed that they had found a TZO, which they named HV 2112. The star was in a dwarf galaxy 199,000 light-years away from Earth. HV 2112 resembles a very bright red supergiant. However, it is considered a TZO because it contains large amounts of some elements that are not released by typical red supergiants.

The roundest star

We often think that planets and stars are round even though they are not. They are actually wider along their equators due to the centrifugal force that occurs when they rotate. Approximately 5,000 light-years away from Earth lies Kepler 11145123, a star that is the roundest natural object known to exist at this time. Typically, the faster the rotation, the wider the star or planet is at the equator. Earth is not perfectly round. The Sun and star Kepler 11145123 aren’t, either. However, Kepler 11145123 comes close.

Earth is 21 kilometres (13 mi) wider at its equator than at its poles. Using that same relative measurement, the Sun is about 10 kilometres (6 mi) wider and Kepler 11145123 is only 6 kilometres (4 mi) wider. This is especially impressive because Kepler 11145123 is twice the size of the Sun. Astronomers concede that their diameter estimate for Kepler 11145123 may be off by a couple of kilometres. That’s a small margin of error, though. On average, the diameter of Kepler 11145123 is 3.2 million kilometres (2 million mi).

A star smaller than Jupiter

We often consider stars to be large heavenly bodies, even though that is not always so. They could be much smaller, say the size of Saturn. Compared to Earth, Saturn seems huge: Approximately 764 Earths would fit into Saturn.

However, that is still much smaller than the size of our Sun. About 1.3 million Earths would fit into the Sun. Saturn is also smaller than Jupiter, the largest planet in our solar system. Nevertheless, astronomers have discovered a star that is the size of Saturn. That star is EBLM J0555-57Ab, which is 600 light-years away from us.

EBLM J0555-57Ab would not have enough internal pressure for nuclear fusion to occur if it were smaller. As we mentioned earlier, nuclear fusion is how stars produce heat and light. This size is just right to meet the minimum mass requirements for nuclear fusion in a star. Anything smaller and it would have been a brown dwarf—one of those failed stars with insufficient mass for gravity to cause nuclear fusion.

The double double star

The Epsilon Lyrae multiple star system is 160 light-years away from Earth. This fascinating system contains a bit of a surprise. It looks like a binary system where two stars are orbiting each other. But upon closer examination, each of those stars is a binary itself. In other words, each star is really two stars orbiting each other. Each pair also orbits the other pair. As a result, the system contains two binaries within a binary (aka “The Double Double”).

From Earth, each stellar pair seems so close together that we could confuse both stars in each set for a single star. This happens even though these individual stars are actually so far apart that they take around 1,000 years to complete a single orbit around the other in its stellar pair. The binaries themselves are also far apart. The distance between the two sets is 10,000 times the range between the Earth and the Sun. The binaries require around 500,000 years to complete a single revolution around each other.

Interestingly, astronomers have discovered a fifth star that orbits one of the stellar pairs. These space scientists also believe that other undiscovered stars are orbiting in Epsilon Lyrae. In all, astronomers think the system involves 10 stars.

The star with a tail

When we think of tails in space, we usually envision comets. Mira (“Wonderful”) is here to prove us wrong. It is a binary star in the Cetus constellation 350 light-years away from Earth. One star is a red giant called Mira A, and the other is a white dwarf called Mira B. A red giant is a dying star, while a white dwarf is a dead star.

Astronomers detected the stars while checking out the universe in ultraviolet light. They found that some comet had left a tail that was 13 light-years long. That is 20,000 times the average distance between Pluto and the Sun. However, they soon discovered that the tail was actually coming from the red giant Mira A.

The tail is shedding several elements, including carbon and oxygen, which astronomers think could create new solar systems. Mira has been releasing these elements for over 30,000 years

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badbackgroundscience · 6 years

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Where does he get those wonderful toys?

It’s the first BBS post without Stan Lee in the world. A sad time, indeed. He wasn’t a perfect man, but he brought inspiration to millions (perhaps even billions) of people with the characters and stories he helped create.

And thus we continue as always, this time with Marvel’s First Family - getting kidnapped by a Soviet cosmonaut and his band of mutant anthropoids* they last saw stranded on the Moon in F4 #13.

While we don’t get an explanation for how they managed to make it back to Earth,** we do get a correction in terms of the science between the two issues.

Previously, everyone was allowed to run around on the surface of the moon sans spacesuits. (Though, to be fair, that’s Uatu’s fault.)

Now, Ivan Kragoff - aka the Red Ghost (aka Beardless Soviet Santa) - plans on killing the team by smashing them onto the lunar surface and dying from the lack of atmosphere. You know...instead of the force of slamming into the surface.

As I mentioned in that previous post, there technically is a super duper thin atmosphere on the Moon, but it’s not made of anything you’d want to breathe. So Kragoff’s not too wrong.

Unfortunately for him, Sue manages to trap just enough oxygen in a forcefield before the crash (that they weren’t even injured by) and the Thing digs them over to Uatu’s house.

And then they get to check out his toys.

Ah, another complete misunderstanding of evolution. It’s not like Pokemon (or that infamous episode of Star Trek Voyager) - it takes place over generations, not within a single individual.

The whole point of evolution is about small genetic changes that get passed down. Sometimes it happens in the “survival of the fittest” way, where a new trait makes it easier to survive (e.g. better access to food, better avoidance of becoming food) to the point where you can make babies and pass that trait down. Sometimes that new trait just makes you slightly more attractive to a sexual partner so you’re more likely to get some (and thus have babies). And sometimes a trait has no benefit but it gets passed down ‘cause it doesn’t kill you before you have babies.***

Now, technically, there are going to be cells in your body that have slightly different DNA than all the others. This is because every time your DNA gets copied to make new cells, there are always going to be errors. Your cells have a natural “autocorrect” proofreading that fix most of those errors, but it’s not 100% effective.****

Does that mean if you managed to live for 20,000 years, your DNA would be so different you’d grow large ears and a lumpy forehead? No. Modern humans have existed for hundreds of thousands of years, and we’ve barely changed in physical appearance. There are some differences, sure, but nothing so drastic.

Perhaps counterintuitively, our brains are smaller than what they were 100,000 years ago. This of course does not mean we’re dumber, as there are many animals on this planet with brains physically larger than ours that are not capable of sending members of their own species to the Moon.

We’ve also grown a lot more diverse in physical appearance, because as we spread around the globe we got exposed to different environments which favored different adaptations, from skin color to hair texture to nose shape.

[Bonus: I will point out that ever since we started regularly using forks way more people naturally have overbites. (Close your mouth right now. Are your top teeth resting forward of your bottom teeth, or do the tips of your teeth naturally touch?) That has nothing to do with genetics, though. So sometimes, changes in biology have nothing to do with genetic drift and everything to do with new cultural behaviors.]

Now, toy number two:

A planet 30 times larger (by which I take to mean “more massive”) than our Sun is - while maybe not impossible if engineered to exist - does not exist in nature. The only bodies in the known universe with the mass of a 30-solar mass star are, well, the pretty rare occurring 30ish-solar mass stars (e.g. θ1 Orionis C),***** and some black holes.

A planet with the mass of 30 Suns (i.e. 60 million trillion trillion kg) but the density of Earth would have a radius of about 2 million km, ~350 times that of Earth’s.

The most massive planet we’ve managed to find (in our limited few decades of exoplanet hunting) is many times that of Jupiter, but it’s hard to pin down exactly what body it actually is, because the line between “a failed star aka a brown dwarf” and “just a really fat gas giant” is ambiguous. For example, NASA’s exoplanet archive lists HR 2562 b, with a mass 30 (+/- 15) times that of Jupiter, as the most massive exoplanet, but it’s also classified as a brown dwarf.

The largest radius we’ve managed to measure is about 30 times that of Earth (specifically, 3 times that of Jupiter). Nowhere near 350x. And it’s, as you should expect, a gas giant.

No wonder Uatu bottled it like Kandor. That’s a really special planet!

[Bonus 2: I wrote about a much more extreme version (i.e. 2000 instead of 30x) a while back.]

* “Anthropoid” just means vaguely resembling the look of a human, and is used both to refer to apes and monkeys. I’m using it because the comic does, but really, almost all the aliens we run into in these comics are anthropoid, unless it’s a Skrull who shapeshifted into a cow.

** or why the gorilla, orangutan, and baboon have un-turned on their master

*** This is one of the arguments for why we still have butt hair.

**** From Nature:

“DNA polymerase enzymes are amazingly particular with respect to their choice of nucleotides during DNA synthesis...Nonetheless, these enzymes do make mistakes at a rate of about 1 per every 100,000 nucleotides. That might not seem like much, until you consider how much DNA a cell has. In humans, with our 6 billion base pairs in each diploid cell, that would amount to about 120,000 mistakes every time a cell divides!...Proofreading fixes about 99% of these types of errors...After replication, mismatch repair reduces the final error rate even further.”

***** The more massive the star, the rarer it is. Even stars with masses like our Sun are more massive than like 70ish percent of all the stars in the galaxy, if not more if you classify brown dwarfs as stars.

#comics #fantastic four #Astronomy #space #planets #physics #biology #evolution

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bobmccullochny · 4 years

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February History

February 4 World Cancer Day

1703 - In Edo (Japan), 46 of the Forty-seven Ronin committed seppuku (ritual suicide) for avenging their master's death.

1783 - Britain declared a formal cessation of hostilities with its American colonies, the United States.

1789 - George Washington was elected as the first president of the United States by the Electoral College.

1801 - John Marshall was sworn in as Chief Justice of the United States.

1825 - The Ohio Legislature authorized the construction of the Ohio and Erie Canal and the Miami and Erie Canal

1826 - The Last of the Mohicans by James Fennimore Cooper was published

1922 - Ford Motor Company acquired the failing luxury automaker Lincoln Motor Company for $8 million.

1932 - The Winter Olympics were held in the United States at Lake Placid, NY.

1935 - Mrs. Wiggs of the Cabbage Patch premiered on CBS radio.

1936 - Radium (Ra) became the first radioactive element to be synthetically made.

1938 - Snow White and the 7 Dwarfs was released by Walt Disney.

1941 - Roy Plunkett received the patent (#2,230,654) for Tetrafluoroethylene Polymers' (Teflon)

1941 - The USO (United Services Organization) was founded.

1957 - Smith-Corona began selling portable electric typewriters.

1961 - The Misfits, starring Marilyn Monroe, Clark Gable and Montgomery Clift, was released by United Artists

1965 (Earthquake) Rat Islands, Alaska

1974 - The Symbionese Liberation Army abducted 19 year-old Patty Hearst

1979 (Earthquake) Riobamba, Ecuador

1983 - Singer Karen Carpenter died of anorexia.

1985 - President Ronald Reagan's defense budget called for a tripling of the expenditure on the "Star Wars" research program.

1991 - Pete Rose (aka Charlie Hustle) was banned 'for life' from the Baseball Hall of Fame due to the fact that he used to illegally gamble on games.

1992 - A coup d'état was led by Hugo Chávez against Venezuelan President Carlos Andrés Pérez.

1997 - A civil jury in California found O.J. Simpson liable in the death of his ex-wife Nicole Brown Simpson and Ron Goldman. Goldman's parents were awarded $8.5 million in compensatory damages.

2004 - Facebook launched as "TheFacebook.com"

#today's smile #history #February

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bobmccullochny · 5 years