#arcsecond

[tenth-sentence]

This is the distance of a star from the Sun that has a parallax of 1 arcsecond.

"Human Universe" - Professor Brian Cox and Andrew Cohen

[saint-vagrant]

sketches of daniel & enver — one arcsecond / the solar system. you'll be seeing em

[hardpacker]

i wrote a character study that ended up becoming a whole short story about Enver, and to a lesser degree Dan (from my comic...s.) i'm somehow shockingly not embarrassed of it and think it turned out pretty alright, so like i want people to see it! it's a bit heavy, and a google doc seems suspect so i stuck it on ao3. not all of it's up yet, maybe half...? yeah like half. but it's complete so i'll do the rest soon.

also it's got big time porneaux! and mind the warnings extremely!

THE THAW (1967-1987)

suggested listening

Black Tape For A Blue Girl

Again, To Drift (For Veronika)

Dagger

I Have No More Answers

Eating Rose Petals

I betray myself / for years on end / breathing is so difficult / when you’ve chosen to suffocate

[thefunkyperson]

Just spent a solid 30-40 minutes getting as accurate of data possible just to calculate how much stars drift to a trillionth of an arcsecond.

FOR FUN.

THIS WASN'T EVEN FOR A PROJECT OR ANYTHING.

JUST SOMETHING I WANTED TO DO

PLEASE HELP I DON'T KNOW WHAT I'M DOING WITH MY LIFE

[wonders-of-the-cosmos]

Occultations by the Moon

The term occultation is most frequently used to describe lunar occultations, those relatively frequent occasions when the Moon passes in front of a star during the course of its orbital motion around the Earth. Since the Moon, with an angular speed with respect to the stars of 0.55 arcsec/s or 2.7 μrad/s, has a very thin atmosphere and stars have an angular diameter of at most 0.057 arcseconds or 0.28 μrad, a star that is occulted by the Moon will disappear or reappear in 0.1 seconds or less on the Moon's edge, or limb. Events that take place on the Moon's dark limb are of particular interest to observers, because the lack of glare allows easier observation and timing.

The accurate timing of lunar occultations is performed regularly by (primarily amateur) astronomers. Lunar occultations timed to an accuracy of a few tenths of a second have various scientific uses, particularly in refining our knowledge of lunar topography. 

source

image credit: Tom Fleming, Elias Chasioti, Delberson Souza, Bob Schiff, Fausto Lubatti, Sergio Scauso

[andmaybegayer]

Huh. Mercury orbits so close to the sun that its orbit is measurably affected by relativistic effects, so it precesses slightly faster than you would expect under Newtonian mechanics alone. That's so neat!

This discrepancy was known as far back as the mid 1800's and caused a hunt for a nonexistent planet to explain the force. It's always funny to read these, like, we only just began to understand germ theory in the 1850's but we were able to measure a 38 arcsecond per century discrepancy in the precession of Mercury.

[talonabraxas]

Sirius A & B Double Star Orbits The brightest star in our sky, Sirius, and its white dwarf companion, Sirius B, are currently farthest apart from our perspective. The two stars orbit each other with a period of about 50 years, and they’re having their maximum separation of 11 arcseconds now.

[messier51]

Regarding your post about solar eclipses on other planets - I know other planets get solar eclipses, too, but do any other planets besides earth get total solar eclipses?

Yep! I mean, that's why I worded that post specifically that way, and included links to the wikipedia articles about solar eclipses on the gas giant planets in our solar system.

So, a total solar eclipse happens on earth because the angular size of the moon as seen from the surface of the earth is (usually) larger than the angular size of the sun, right? (We see an annular eclipse when the moon's angular size is a little smaller than the sun's, depending on the relative distances of each since orbits are elliptical and those aren't constant.)

Jupiter, Saturn, Uranus and Neptune are all quite a bit farther from the sun, so the angular size of the sun is much smaller, and have fairly large moons. All of Jupiter's galilean moons are large enough and close enough to the planet that they're large enough to fully occult (cover) the sun and therefore produce total eclipses.

Similarly on Saturn:

Seven of Saturn's satellites – Janus, Mimas, Enceladus, Tethys, Rhea, Dione and Titan – are large enough and near enough to eclipse or occult the Sun, or in other words to cast an umbra on Saturn. At this distance, the sun covers only about 3 arcminutes in the sky of Saturn. In comparison, the seven major moons of Saturn have angular diameters of 5–10' (Mimas), 5–9' (Enceladus), 10–15' (Tethys), 10–12' (Dione), 8–11' (Rhea), 14–15' (Titan), and 1–2' (Iapetus). Iapetus is Saturn's third largest moon, but is too far away to completely eclipse the Sun. Janus, a very close moon to Saturn, has an angular diameter of about 7', meaning that it can fully cover the Sun.

and Uranus:

Twelve satellites of Uranus—Cressida, Desdemona, Juliet, Portia, Rosalind, Belinda, Puck, Miranda, Ariel, Umbriel, Titania and Oberon—are large enough and near enough to eclipse the Sun.

and Neptune:

All of Neptune's inner moons and Triton can eclipse the Sun as seen from Neptune. All other satellites of Neptune are too small and/or too distant to produce an umbra. From this distance, the Sun's angular diameter is reduced to one and a quarter arcminutes across. Here are the angular diameters of the moons that are large enough to fully eclipse the Sun: Naiad, 7–13'; Thalassa, 8–14'; Despina, 14–22'; Galatea, 13–18'; Larissa, 10–14'; Proteus, 13–16'; Triton, 26–28'.

and also Pluto, really:

Charon has an angular diameter of 4 degrees of arc as seen from the surface of Pluto; the Sun appears much smaller, only 39 to 65 arcseconds. By comparison, the Moon as viewed from Earth has an angular diameter of only 31 minutes of arc, or just over half a degree of arc. Therefore, Charon would appear to have eight times the diameter, or 25 times the area of the Moon; this is due to Charon's proximity to Pluto rather than size, as despite having just over one-third of a Lunar radius, Earth's Moon is 20 times more distant from Earth's surface as Charon is from Pluto's. This proximity further ensures that a large proportion of Pluto's surface can experience an eclipse. Because Pluto always presents the same face towards Charon due to tidal locking, only the Charon-facing hemisphere experiences solar eclipses by Charon.

So all of these planets (modulo the lack of surfaces/living beings, but like, that's also pretty special to Earth completely separately from eclipses) experience the nighttime-like darkness caused by the umbra (shadow) of the eclipse (occultation).

Now, as a few people have pointed out in the notes, the ring of fire deal IS pretty special, which happens because the angular size of the moon and sun are often SO similar. (Maybe Iapetus is similar enough with the solar angular size sometimes depending where Saturn is in its orbit, but at a few arcminutes instead of half a degree you can imagine the effect being somewhat less amazing. Then again, I bet solar occultations by Saturn's rings are pretty amazing, so I'm not going to hold that against the planet.)

In no way do I think this makes total solar eclipses less awesome, or think that the excitement is misplaced. It's a pretty amazing special event! It's also one that won't even exist for the earth forever, since the moon moves a few centimeters away from us each year. But as an astronomer I think it's cool that there are eclipses (and occultations and transits of the sun by moons with smaller angular sizes!) on other planets too! Though, the post I made was mostly a kneejerk eyeroll complaint about a silly factual error that might just be because the OP of the post I was annoyed by was thinking about some other facet of our solar eclipses as being unique than how it was worded. Since we can't go to any other planet to watch eclipses (that would add a whole extra layer to astrotourism), our eclipses on earth are pretty special. If you ever have the opportunity to see one, I wholly recommend going! It's really amazing.

In conclusion: here's an Io solar eclipse on Jupiter taken by the Hubble Space telescope:

[Image in black and white shows Jupiter's volcanic moon Io passing above the turbulent clouds of the giant planet, on July 24, 1996. There's a large black spot on Jupiter which is Io's shadow. The smallest details visible on Io and Jupiter are about 100 miles across (about 160 kilometres). Bright patches visible on Io are regions of sulfur dioxide frost. Io is roughly the size of Earth's moon, but 2000 times farther away.]

And here's the April 8th eclipse of the sun by the moon on Earth as seen by the GOES satellite:

[A gif of the earth showing the GOES EAST view of North and South America on April 8th over the course of the total solar eclipse. A shadow of the moon passes from the left to the upper right side of the view of the earth.]

[livingforstars]

VLT: A New 'Largest' Optical Telescope - September 1st, 1996.

"What is the largest telescope in the world? In the optical, this title was long held by the Hale 200-inch. But an even larger optical telescope was built. Dubbed the Very Large Telescope (VLT), the European Southern Observatory (ESO) built four 8.2 metre mirrors in Chile, which together act as a single telescope with a mirror diameter of over 16 metres. The first of these telescopes would be completed in 1997, and all four would be completed and working together in the year 2000. The VLT would use active optics to create sub-arcsecond resolution. This, combined with the enormous light-gathering power, would allow astronomers to explore dim objects in our galaxy and the early Universe."

[mapsontheweb]

Washington State's South Cascades Elevation Map

by u/acomfysweater

Hi, I got the data using the USGS's earth explorer. I extracted a SRTM tile at 1-arcsecond resolution (3601x3601 pixels) in a latitude/longitude projection (EPSG:4326). It was reprojected into EPSG Projection 2286 - NAD83 / Washington South (ftUS). I utilized John Nelson's method to hillshading, as well as this terrain tooletset: https://www.esri.com/arcgis-blog/products/3d-gis/3d-gis/terrain-tools-1-1-released

I used ArcGIS Pro to make the map.

[theexclusivestory]

Stellar Parallax: Peering into the Depths of the Universe

In the huge space of the universe, where stars sparkle like faraway lights in the dark sky, there's something special called stellar parallax. This idea has helped us learn a lot about the universe. It allows astronomers to measure how far away stars are, draw maps of our galaxy, and the Milky Way, and explore space better than ever. In this article, we'll look at stellar parallax, where it came from, and how we use it today.

Understanding Stellar Parallax

Stellar parallax happens because the Earth moves around the Sun. When this happens, stars closer to us seem to move a little compared to stars farther away. This movement is called parallax. If a star is really close to Earth, it will seem to move a lot. Astronomers use this movement to figure out how far away a star is.

Imagine you're looking at your finger with one eye closed, then you switch eyes. Your finger seems to move against the background, right? That's like what happens with stars. When Earth moves around the Sun, the closer stars seem to shift their position against the farther ones. It's like the finger movement but on a huge scale because stars are incredibly far away. This shifting is what we call stellar parallax.

Historical Perspectives

For many years, astronomers were fascinated by the idea of stellar parallax, which could help measure how far away stars are. But they couldn't observe it because their tools weren't advanced enough. In the early 1600s, Johannes Kepler, a famous astronomer, suggested that stellar parallax could be used to measure distances to stars. However, it wasn't until the 1800s that technology improved enough for astronomers to actually see and measure stellar parallax.

In 1838, a scientist named Friedrich Bessel did something incredible. He used really good tools and paid close attention to detail to measure something called "stellar parallax." This is when stars seem to move slightly because of the Earth's movement. Bessel focused on a star called 61 Cygni and found out how far away it was using this method. This was a big deal because it showed that we could figure out how far away stars are by watching how they move. Bessel's work was super important and started a new way for scientists to explore space.

Principles of Measurement

Measuring stellar parallax is like using a ruler to figure out how far away something is. Instead of a ruler, astronomers use the Earth's orbit around the Sun. When the Earth is on one side of the Sun, and then on the other side six months later, stars seem to move slightly against the background. It's like looking at your finger with one eye closed and then switching eyes. By measuring this tiny shift in a star's position from different points in Earth's orbit, astronomers can calculate how far away the star is. This helps us understand the distances to stars in space.

The angle of parallax, denoted by the symbol θ (theta), is inversely proportional to the distance to the star. This means stars with larger parallaxes are closer to the Earth, while those with smaller parallaxes are farther away. To convert the angle of parallax into a distance measurement, astronomers use the formula:

Distance to star (in parsecs) = 1 / parallax angle (in arcseconds)

This fundamental relationship forms the basis for determining the distances to stars through stellar parallax.

Modern Applications

In the modern era, stellar parallax remains an invaluable tool for astronomers seeking to unravel the mysteries of the cosmos. With advancements in technology and observational techniques, astronomers can now measure stellar parallax with unprecedented precision, extending our cosmic reach to the farthest reaches of the galaxy.

One of the most notable applications of stellar parallax is in the construction of the cosmic distance ladder, a hierarchical series of distance measurement techniques used to determine the distances to celestial objects at various scales. Stellar parallax serves as the first rung on this ladder, providing accurate distance measurements to nearby stars within our own Milky Way galaxy.

Beyond our galaxy, stellar parallax has been instrumental in measuring the distances to nearby galaxies, such as the Andromeda galaxy (M31) and the Large Magellanic Cloud. By observing the parallax of stars within these galaxies, astronomers can calibrate distance indicators and estimate the vast distances to extragalactic objects.

Furthermore, stellar parallax plays a crucial role in the search for exoplanets – planets orbiting stars outside our solar system. By measuring the tiny wobbles in a star's position caused by the gravitational pull of an orbiting planet, astronomers can infer the presence of exoplanets and even estimate their masses and orbital parameters.

Challenges and Limitations

Even though stellar parallax helps us measure distances to stars, it has some drawbacks. One big problem is that we can only use it for stars relatively close to us. This is because we rely on the Earth's movement around the Sun to observe the parallax, and our orbit provides a limited viewing angle. So, we can only accurately measure the distance to stars within a few hundred parsecs, which is still quite far in space terms. This means that for stars farther away, we need other methods to figure out how far they are from us.

When astronomers measure stellar parallax, they face some challenges. These include mistakes in observations, stars moving, and dust between us and the star. Especially when dealing with stars that are faint or very far away, these factors can make measurements uncertain. To overcome these challenges, astronomers use smart methods and math tricks. They analyze data carefully and apply statistical tools to make sure their distance measurements are as accurate as possible. This way, they can still figure out how far away stars are, even with these obstacles in their way.

Looking to the Future

As technology gets better and we find new ways to look at the stars, stellar parallax will become even more important for studying space. It will help us learn more about faraway galaxies and find new planets beyond our solar system. So, as we keep exploring the universe, stellar parallax will remain a key tool for understanding how everything works out there.

In the next few decades, new missions in space and observatories on Earth will help us get even better at measuring stellar parallax. This will give us a clearer view of the universe. Every new thing we learn brings us a step closer to understanding the universe and figuring out where we fit into it.

Conclusion

Stellar parallax stands as a testament to humanity's insatiable curiosity and relentless pursuit of knowledge. From its humble beginnings in the minds of ancient philosophers to its modern-day applications in cutting-edge astrophysics, stellar parallax has reshaped our understanding of the cosmos and illuminated the vastness of space in ways previously unimaginable.

As we continue to gaze up at the stars and ponder the mysteries of the universe, let us remember the profound insights afforded to us by stellar parallax – a celestial phenomenon that has forever changed the way we perceive the cosmos and our place within it.

FAQs

What is the largest stellar parallax? Proxima Centauri is the closest star to Earth. It's about 4.3 light-years away, which is really far—nearly 300,000 times farther than the distance from Earth to the Sun! Its distance is measured using something called parallax, which is like the apparent shift in position of an object when viewed from different angles. Proxima Centauri has the biggest parallax we've seen among stars, showing how close it is compared to others in space.

What is the difference between parallax and stellar parallax? Stellar parallax is like when you hold your finger in front of your face and close one eye, then switch eyes. Your finger appears to move against the background. Similarly, when we look at stars from different positions in Earth's orbit around the Sun, nearby stars seem to shift against the backdrop of distant stars. Scientists use this shift, called stellar parallax, to figure out how far away the stars are. It's like measuring the distance by comparing angles, kind of like how you might estimate the distance to an object by looking at it with one eye, and then the other.

What are the two limits to stellar parallax? When we observe stars from Earth, we can only measure their distances accurately up to a certain point. This is because we use the Earth's orbit around the Sun as a reference, and smaller angles are harder to measure precisely. So, stars farther than about 100 parsecs away (a unit of distance in space) are difficult to measure accurately from Earth because their parallax angles (the apparent shift in position when viewed from different points) are too small to measure well.

What is the smallest parallax? Stellar parallax is a way to measure how far away stars are by looking at how they appear to shift against the background of more distant stars as the Earth moves around the Sun. Stars are incredibly far away, so this shifting is very tiny and hard to detect. The smallest shifts we can measure right now are about 0.001 arcseconds, which means the star is about 1000 parsecs away.

Read more

[oliviabutsmart]

Physics "Friday" #9 [OPINION]: Is Fahrenheit the better temperature scale?

So as the title suggests, this post is a lot less facts and logic, and a lot more opinionated. It is still physics-y I just believe it's an interesting way to delve into a subject by turning it into an opinionated peice.

Preamble: A summary of Metric vs. Imperial arguments

Education level: Primary (Y3/4)

Topic: Measuring Systems (Metrology)

Now before you throw your hands up at the title and your silly little internet brain is like "this silly impericuck is fahrenpilled!" ... I'm an astronomy student living in Australia - I use SI units (and other unit systems) on the daily.

Though ... it is pretty notorious in astronomy to use like 17 different unit systems. Here's a list of examples:

My beloved SI units

CGS Units

Whatever the fuck a Jansky is

Don't even start with natural units I can't live without big G

"Ampere in CGS units is g1/2 cm3/2 s−2"

Solar Luminosity/Mass of Sun

Angstroms (like please can we just use nanometers?)

How many Jupiters or Earths fit into this cloud of gas?

The vomit of parallax units i.e. AU, pc, Mpc, arcseconds, radians

Steradians (Solid angles can be finicky)

Logarithms, logarithms everywhere!

Hubble's constant being in km/s/Mpc but then having to turn that into Hz or per year - like can someone please acknowledged how cursed this is?

When you do Kepler's 3rd law on Mercury and realise it doesn't work (because you forgot Einstein existed) ... so no units end up working

ADUs and/or whatever you get when you deal with telescope outputs

And as an Australian, I use SI units very regularly. Only measurements of human height and cooking weights are really imperial. And I can express all of them in metric units.

Now generally, the Metric (or SI) units are better than the imperial (or USC) units. The main points in favour of SI are:

(Almost) Everybody uses it

It's basically universal in science (see exceptions above)

It fits well with our base 10 counting system, easy scaling (e.g. 1 kg = 1 000 g = 1 000 000 mg)

It's directly pinned to many natural constants and unchanging laws

Different units interact with eachother much better

Now, generally, the main arguments for imperial units involve a bunch of patriots™ screaming about how "THIS IS THE CoUNTRY OF FREEDOM AND GOD!! AND I AIN'T USING NO CHINESE UNITS!!!1!".

That, or how metrification is hard. Which, well, metrification can occur over the course of decades, literally teaching your kids metric helps the country adjust to a metric system.

The best arguments I've found for imperial units is as follows:

Numbers like 6, 12, 60 etc. - i.e. units based on highly composite numbers - are very easily divisible by 2, 3, and 4

Units like feet, inches, pounds, stone, etc. are of a much more human-friendly scale. Because these units are based on bodily proportions or common objects

Generally, the arguments for metric vastly outweigh the arguments for imperial. And the main reason why is that the two arguments for imperial conflict with eachother. You cannot easily subdivide your units neatly and have human units.

For example, the Roman mile is a unit that measures the usual amount of distance a footsoldier can cover before needing a short stop. An acre is the amount of land that a manual-labour farmer can cover in a day's work. An inch is about the size of your thumb.

The problem is that all three of these units, based on length, are completely off kilter. 1 acre = 43,650 square feet, 1 Roman mile = 58260 in, etc.

The only cases where I would say the human-ness and divisibility of units actually becomes a stronger argument than decimalised units are, time and temperature.

Time is obvious. 1 hour = 60 minutes = 3600 seconds. It's nice, clean and simple. And an hour or half-hour is a very human unit, the same as a second or a minute. We often operate on hour and minute schedules, and that's not just because of capitalism. 30 minutes just appears to be the amount of time we like to work before taking a short rest.

Temperature is a bit more nebulous however ...

Where (I think) Celsius fails

Of course, celsius is an understandable scale. 0 C = Water Freezes, 100 C = water boils. Pinning your scale on water makes life easy for you as you know what the bounds are.

The problem is that there are temperatures that exist outside of the 0-100 scale. And this kinda breaks the neat decimalisation of a scale.

A cold winter's day in Tasmania could drop into the negatives. And just because your in the negatives doesn't mean ocean water or rain will freeze. Temperatures below 0 C doesn't guarantee snowfall.

Similarly, say you are in a desert during the day. The temperature can get as high as 50 C - it's reasonable to say that you're unlikely to see temperatures above 50 C outside of your oven or kettle.

Do you normally see temperatures between 70 - 90 C? Unless if you're pasteurising milk, distilling alcohol, or doing chemistry, you are not going to encounter these temperatures. And do you really need your temperature numbers to be below 100 to do chemistry?

This is the downside of Celsius. Because temperature is a scale, and operates differently to other units, it doesn't really matter where you set the zero point. A boiling point of ethanol at "78" is no better than one at "173".

Celsius also doesn't account for temperatures that are very well below the freezing point of water, temperatures which are very common to experience.

So is Fahrenheit Better?

Fahrenheit solves this problem, partially. It's a more human friendly scale. 0 F is a very very cold day whereas 100 F is a very very hot day. Things beyond both numbers are relegated to the scientists, chefs, and extremophiles of the world.

If we were to completely remove all requirements of not pissing off a bunch of people, we could even create our own temperature scale to make things even better: 0 X = -50 C and 100 X = 50 C.

Even better because now the 0 and 100 of this scale becomes the absolute limit of what we could normally experience on earth, the hottest desert and the coldest tundra. It even comes with the benefit that 50 X = the freezing point of water and 150 X = the boiling point of water - it preserves our common "anchors" of the phases of water.

The problem is that there's a second hidden benefit of Fahrenheit: it's specificity. What do I mean by that?

Well, for every 1 C increase in temperature, the Fahrenheit scale increases by 1.8 F. This means that a temperature of 20 C could mean 68 F or 69 F.

For a lot of normal/casual processes, the Celsius scale may require us get past the decimal point, to express minor changes in temperature, whereas Fahrenheit would not.

For chemistry and physics, our significant figure requirements immediately become extra precise. 58.8 F is a more accurate measurement than 14.9 C, without requiring any more decimal places.

You may say "well why not we use a deci-Celsius scale where 1000 dC = boiling point of water". The issue is that too much precision may be putting it over the top. We don't measure the size of cities in centimetres.

But then what about Kelvin

Of course, the main SI unit for temperature, and the unit physicists and chemists use is the Kelvin. The reason for this is of course:

It is tied to absolute zero by setting it to 0 K

Because of this, we can apply SI order of magnitude quantifiers like milli-Kelvin, kilo-Kelvin, Giga-Kelvin without upsetting the position of our anchor points

It covers and measures cleanly low-K processes

Very hot processes end up having Celsius be approximately equal to Kelvin

It would be difficult to use Fahrenheit because 0 F ~ the freezing point of saltwater.

But let me introduce you to the Rankine Scale. What Kelvin is to Celsius is what Rankine is to Fahrenheit.

Rankine takes all of the benefits of Fahrenheit with it (aside from the human-ness of the scale - but that's not the purpose of the Rankine and Fahrenheit scales), but it also takes the benefits that Kelvin gets.

We can too, have milli-Rankine and Giga-Rankine. And the best part is that it is twice as precise as Fahrenheit.

Even better is that the Rankine Scale is very easily convertible to the Kelvin Scale. 1 K = 1.8 R; 1 K⁻¹ = 0.556 R⁻¹. This means I can very easily re-formulate some fundamental constants:

Boltzmann constant = 1.381 × 10⁻²³ J K⁻¹ = 7.672 × 10⁻²⁴ J R⁻¹

Stefan-Boltzmann c. = 5.67 × 10⁻⁸ W m⁻² K⁻⁴ = 5.40 × 10⁻⁹ W m⁻² R⁻⁴

Ideal gas constant = 8.315 J mol⁻¹ K⁻¹ = 4.619 J mol⁻¹ R⁻¹

Wein's constant = 2.898 × 10⁻³ m K = 5.216 × 10⁻³ m R

Let's hope I converted it correctly, idk my Saturday brain no thinky.

Conclusion: So is it actually better?

Short Answer: In my opinion, yes. But I'm not switching to it.

Of course, when talking about subjective opinions, people can point out the flaws in each others' opinions. I've made it clear that the imperial vs. metric debate very solidly falls to the metric side with only a few exceptions.

Temperature is one of those scales that are more up-to-debate over the usefulness of certain units of choice. Especially because the alternative unit system is still commonly used.

I could've made the same arguments about the meter, and said that we should use a decimalised inch or foot with kilofeet or millifeet. Or invent a completely new unit system that is technically "superior". But that's obviously much more ambitious.

Of course, the likelihood of the global Fahrenheit revolution is almost non-existent, and this is more of a series of "well, technically speaking" arguments that are more for the point of exploring an idea than implementing one.

Regardless I'd like to hear YOUR arguments over why I'm a stupid poo poo head or I'm actually the mother of the next great napoleonic French empire.

I tried to add a bit of colour in this post, specifically with the quotes. I just didn't want it to be a bland wall of text.

Again, feedback that may be unrelated to the specific "you're right/you're wrong" debate like my writing style etc. is also appreciated.

I don't really know what I will do next week. Because technically I was supposed to do philosophy and ethics in science ... but I might not have that time given my university study.

Currently I'm doing three courses in QFT, GR, and Cosmology. And they are all very big and hefty. Thankfully, I think there's a bit of a break period coming as we're now moving to canonical quantisation (which I've found easier than Feynman diagrams), and the measurement of gravitational waves.

Now don't worry that last paragraph is not a flex, it's more an indication that I'm learning a lot of this stuff as I make these posts. More an excuse as to why I might in the future delay posts and such. Like I mentioned the Higgs mechanism in the last post at the same time I was actually learning about the Higgs mechanism.

Anyways, I'm going to go and scarf down some chocolate now.

[saint-vagrant]

I. BIRTH OF THE SUN

II. ONE ARCSECOND

III. ■■■

(redacted until later) my piece for the Shortbox Comic Fair

since december, i've been been focused on what's become 3 new comics ☉ born from 1 core thought and exploded in different, discrete directions... if you've read SUPERPOSE, you may find some themes familiar, but explored in all-new ways.

something something queer trans military intrigue magical realism scifi. you can see more pages and development material (sketches and supplementary illustrations, process, inspirations, thoughts, etc.) for these comics and for SUPERPOSE, from which i've necessarily taken a break to get this work done, at our patreon. it directly supports the creation of these projects. and please check out the SBCF in October!

[gay-victorian-astronomer]

so we’re at the stage where I’m testing my neural network on actual data to see if it finds any promising gravitational lens candidates, and we’re expecting it to also find some amount of galaxies where there’s just two really close together because it’s hard to differentiate those from lenses in spectra.

well, in the most recent round, it found this:

that is four (?!?) galaxies all trying to squeeze themselves into a spectroscopic fiber about one arcsecond in diameter

absolute clown car behavior

[kaiasky]

KAIA YOU FUCKING NUMSKULL WHY WOULD YOU CALL THAT A CHASEPURR WHEN YOU COULD CALL THAT A PURRCHASER IT WAS RIGHT THERE TWO ARCSECONDS TO YOUR LEFT AND YOU DIDNT SEE IT DO I HAVE TO DO EVERYTHNIG MYSELF HERE

whats the pun here? purchaser? what is halimede for catboys purchasing? i mean i guess catboys and catboy accessories but like. standard halimede isn't purchasing luna-terras from the luna terra store she is Fumbling Them. im not sure I understand purrchaser

[stay-with-wonder]

Rigel: Orion's Brightest Star

Rigel is a star you can easily spot in the night sky. It is the brightest star in the constellation Orion (the hunter) and the seventh brightest star in the night sky. But did you know that Rigel is not just one star but a system of four stars? And that is a blue supergiant, one of the most massive and luminous stars in our galaxy? I will be focusing on Rigel and its companions in this post.

What is Rigel?

What are Rigel’s Companions?

Rigel is not alone in its orbit around the center mass of the system. It has three companions: Rigel Ba, Rigel Bb, and Rigel C. These are all main-sequence stars, which means they still burn hydrogen in their cores. They are also blue-white, with spectral types of B9 V. They have similar masses and radii, ranging from 2.94 to 3.84 times that of the Sun and from 2.5 to 3 times that of the Sun respectively.

Rigel Ba and Rigel Bb form a close pair that orbits each other every 9.86 days. They are so close that they cannot be seen separately, even with powerful telescopes. They are called a spectroscopic binary because their orbital motion can be detected by measuring the Doppler shifts in their spectral lines.

Rigel A and Rigel Bc form an even wider pair that orbits each other every 24,000 years. This pair can be seen with binoculars or small telescopes under good conditions.

There is also a fifth star that may be part of the system, but it is not confirmed yet. It is a faint red dwarf star of magnitude 15.3 that lies about 220 arcseconds* away from Rigel A. 

*(Arcseconds, also known as arc-seconds or arc seconds, are a unit of angular measurement used in various fields, including astronomy, geodesy, and navigation. They are a subdivision of an arcminute, a unit of angular measurement equal to 1/60th of a degree.)

How Did Rigel Form and Evolve?

Rigel started as a massive main sequence star that burned the hydrogen in its core very quickly. As the hydrogen was depleted, the star began to contract and heat up, while its outer layers expanded and cooled down. As a result, Rigel became a supergiant star.

Rigel will continue to fuse heavier elements until it reaches iron, which cannot release any more energy by fusion. (Stars undergo fusion reactions in their cores, where lighter elements combine to form heavier elements, releasing energy in the process of fusion. A fusion process continues until the core contains predominantly iron. At this point, the process of fusing iron requires more energy than it releases, slowing down. This process poses a problem because fusion reactions provide the outward pressure that counteracts the inward pull of gravity, supporting the star against collapse. Without the energy generated by fusion, the star loses its means of support and can eventually collapse under its gravity.) At this point, Rigel will collapse and explode into a supernova. But this won’t happen for another million years or so.

The supernova explosion will destroy most of Rigel’s mass and eject it into space as gas and dust. The training core will either become either a neutron star or a black hole, depending on how massive it is.

The fate of Rigel's companions will depend on how close they are to Rigel when it explodes. If they are too close, they will be destroyed or disrupted by the shock wave and radiation from the supernova. If they are far enough, they will survive but may be affected by the change in gravity and radiation from the remnant.

Rigel is important for several reasons. First, it is a prominent star that helps us identify the constellation of Orion and find other stars in the sky. Second, it is a bright and nearby example of a supergiant star, which helps us understand the evolution and fate of massive stars. Third, it is a complex star that challenges our ability to observe and measure its components and interactions. Fourth, it is a potential supernova progenitor that may explode in the near future (in astronomical terms, of course) and provide us with a spectacular show and valuable data.

Rigel is also important for cultural reasons. It has been known and named by many civilizations throughout history, and it has been associated with various myths and legends. In ancient China, Rigel was called Shang Zuo, meaning "the left-hand seat of the king," and it was part of the Three Stars asterism that represented the emperor's throne. In Arabic, Rigel was called Rijl al-Jawza', meaning "the foot of the central one," referring to Orion as a giant. In modern times, Rigel has been featured in many works of science fiction and fantasy, such as Star Trek, The Hitchhiker's Guide to the Galaxy, and The Chronicles of Narnia.

Rigel is a fascinating star that deserves our attention and admiration. It is not only a beautiful sight in the night sky, but also a rich source of scientific information and cultural inspiration. I hope you enjoyed learning about Rigel and its companions, and I encourage you to look for them the next time you gaze at the stars. And as always, this blogger has to sign out, Stay With Wonder!