Sign-ups

Jun. 26th, 2017 08:53 pm
evil_plotbunny: (Default)
[personal profile] evil_plotbunny posting in [community profile] fic_corner
Sign ups are due to end in 48 hours. What time is that for me?

I'm a little worried because we're currently under 20 sign-ups and I'm not sure if we're going to get enough to make matching possible. Hopefully everyone's waiting till the last minute. Hopefully everyone's waiting till the last minute. Tell your friends, tell your enemies. Encourage them to sign up!
[syndicated profile] badastronomy_feed

Posted by Phil Plait

Mars is smaller than Earth. It’s only half as wide, with less than a third of the surface area of our fair blue-green world. That makes it seem downright diminutive.

But don’t be fooled. It has 145 million square kilometers of surface area, a vast stretch of real estate that makes it incredibly easy to get lost in.

And that is why I do so love images like this: The Curiosity rover crawling over the surface of Mars, as seen from orbit:

The Mars Curiosity rover, seen from orbit.

[The Mars Curiosity rover, seen from orbit: It's the tiny blue dot in the center. Credit: NASA/JPL-Caltech/Univ. of Arizona]

That stunning shot was taken by the HiRISE camera on board the Mars Reconnaissance Orbiter, and in this color-enhanced image, the rover shows as a bright blue dot (right in the center) standing out against the red rocks and dust of Aeolis Mons, a mountain colloquially known as Mt. Sharp.

MRO was 271 km (170 miles) above the rover when it took that image, and it can resolve objects down to about 80 centimeters (a little over 2.5 feet) across. Curiosity is about 3 meters long, so it shows up as a barely resolved feature.

Curiosity landed on Mars on August 5, 2012, inside Gale crater. It immediately started investigating its surroundings, and over the past five years has been going up the northwestern flank of Aeolis Mons, the central peak that formed after a monstrous impact carved out the crater billions of year ago. The crater is over 150 km across, and Aeolis Mons stands over five kilometers high.

When the image from HiRISE was taken, Curiosity was on its way up the mountain to “Vera Rubin” ridge, where hematite was found using mineral mappers from orbit. Hematite can form in standing water, so the rover is investigating the area to look for other signs of the ancient lake known to have once existed surrounding the mountain (the crater is well over 3 billion years old, and sometime after it formed it filled with water, now long since gone). Vera Rubin, by the way, was an astronomer who pioneered the search for dark matter, the mysterious substance making up the vast majority of all matter in the Universe, but which is invisible to our telescopes.

After more than 1720 sols on Mars —a day on Mars is about 24.5 hours, so planetary scientists call them “sols” to distinguish them from Earth days— we’ve gotten used to images from Curiosity’s point of view. Like this one, for example, showing what Curiosity saw the day the image from orbit was taken:

 

[View of the flanks of Aeolis Mons by Curiosity. Credit: NASA/JPL-Caltech/MSSS]

Though still to my eye beautiful, sometimes exquisitely so, these images show Mars to be dry, dusty, forbidding. The barrenness is complete. There are no humans on Mars, no life at all that we know of; as a popular meme put it, Mars is the only known planet to be inhabited solely by robots.

Seeing those pictures from the surface is awe-inspiring, but they show how lonely it is there. Somehow, for me, it’s the images from orbit that drive that home for me. I’m used to seeing satellite images of Earth, and it seems that no matter where you look you see the influence of life. You have to go out of your way to find a spot with no life, no vegetation, nothing to see but rock and sand.

Yet, on Mars, that’s everywhere. That’s all you get.

... unless you happen to spot the handiwork of humans, a gleaming robot explorer traversing that barren but glorious geology sitting on a planet tens of million of kilometers away at its closest.

Look at it! It is the end product of cooperation around the globe, an aggregate of the knowledge we share with each other, from every scientist, every engineer, every person who has looked up at the stars and wondered about them. No one in the history of our species has lived there, but we go there by proxy partially in the hope that we need not make our last stand on Earth.

It’s testament to our drive to explore, to understand, a “we are here!” shouted to the cosmos. It is a vivid blue dot, illuminated by sunlight, a small player in a vast arena, but one that we know better every day because we choose to explore.

 

Top image: Curiosity self-portrait taken in August 2015. Credit: NASA/JPL-Caltech/MSSS

3

Logo Format

Light Logo

Listicle Format

No Markers

Featured Post

Featured

Article Type

News

Is News

Breaking News

Normal

Standout Article

Image icon curiosity_selfportrait_buckskin2015.jpg

Hide Related Posts & Comments

saekhwa: Crop of Harriet in the school library (inspired to do more)
[personal profile] saekhwa posting in [community profile] fandomcalendar
DCMultiversity-Promo-Multifandom
Graphic created by dungeonmarm
sign-ups on ao3 | deadlines | faq | rules | pinch hitter sign-ups | contact a mod


Link: [community profile] dcmultiversity

Description: Have you ever read a story and wondered: What an amazing story! But what if…? Well here's your chance to take a crack at that what if. This is an anonymous remix challenge for Arrow, Constantine, The Flash, Legends of Tomorrow, Supergirl, and Vixen.

Key dates:
  • present-July 15: DC Multiversity Remix is open for sign ups

  • July 16: sign ups close

  • July 22: fanworks are assigned to everyone who signed up for the challenge

  • August 5: first check-in

  • August 26: second check-in

  • September 9: remixes due (complete and posted to the DC Multiversity Remix collection on AO3)

  • September 24: DC Multiversity Remix collection goes live

  • October 1: authors revealed

I'm still here, it's getting late

Jun. 25th, 2017 09:16 pm
morbane: pohutukawa blossom and leaves (Default)
[personal profile] morbane
So, hi.

It's winter; the fire's on; the headphones I just accidentally gave a bath to are hung at a strategic distance from it, across the fire-screen, which is an irrelevant piece of furniture because the fire is gas. (It comes in handy when drying clothes, however.)

Offline, I've been settling into my new house. Our longtime friend AC moved in as a flatmate in February, and in April, another old friend, AR, moved back from Scotland and came to live with us for two months while looking for his own place.

The house has been good to us. There was one miserable and expensive week when we checked out some suddenly-blocked drains and the plumbers, while dealing with that (in a temporary fashion - the tree roots that caused the problem have yet to be worked around), alerted us to a gas leak caused by corroded pipes and then arranged for those pipes to be replaced. No hot water for five days while I was in bed with a cold and the tradesmen had to dig a trench through the reinforced concrete that forms the support for the house's front extension. In other house maintenance respects, I am yet to kick into high gear. We need a large pair of curtains downstairs to keep the heat from flowing out and away at the large French doors, and I have not enjoyed my dealings with the curtain consultants thus far. But I love having a spare room. I love being able to offer guests space with a real bed. I love having two ovens. I love the giant converted garage and the view over the valley to the western hills. I love having a bay tree and a lemon tree. I love having a house on street level. Before this, I moved out of my last street-level house in January 2006.

AC is a fantastic fit as a flatmate. She and I share the idea that although other kinds of social interaction are worthwhile, the most pleasant is to be in the same space as someone else, each with a computer, very occasionally remarking on interesting and amusing things that pass our screens. Also, she is a fandom writer and artist. Also, she and Joel have somewhat compatible tastes in games and TV. I have had really good luck in flatmates over my years in Wellington, but in my last major shared flat, my flatmates were the kind of people who are pure introverts when they get home. I respected that, but this is my ideal.

I'm already missing AR a little. Four people in the house was really nice too. AR flatted with me and Joel in 2007-2009, and then flatted with AC and two other friends in 2015, and then he went off to Scotland, and then ten months later he returned. It is a nice way to be tangled together. He's coming around for dinner and boardgames tomorrow night. I hope he brings Codenames. He introduced AC & me to the game last week and I really, really liked it: simple mechanics + word-association problem-solving & teamwork.

There are, of course, also politics going around me and other offline updates, but perhaps another time when I'm not trying to dust this journal off after months of silence. (Joel, btw, is currently in Las Vegas, in the 'holiday' part of a North American business trip.)


Online, I've been struggling to catch up after Yuletide. Here's what's caught my interest:

  • Night on Fic Mountain went live a few days ago, at a solstice. This is a fic and art fandom exchange for rare fandoms - basically, mini-Yuletide on the far side of the year. I used to co-mod it, but nowadays dhampyresa does all the work and only calls on me occasionally. *waves pompoms* I did write a pinch hit, and enjoyed several pieces of art and fiction. Have a look.

  • Alternate Universe Exchange is a new project from Rosencrantz, whom I also team up with when Once Upon Fic comes around (see below). This is a fandom exchange (fic-only) for alternate universe ideas - whether they're of the "but what if Bob didn't die" or the "everyone works in a coffee shop" variety. Tag approving is.... interesting. If you think you might want to nominate, get in quick.

  • Speaking of Once Upon a Fic, that went live in May, and I still have stories to comment on. This is a challenge for interpretations of fairy tales and similar canons, and I love it so much. I was really disappointed in myself that I did not complete a work this year, and I would like one day to make it up to my recipient. Meanwhile, however, the works that were created are brilliant. [livejournal.com profile] bleodswean, I think you in particular would appreciate Children of wild, legends round our neck, must shatter, a 30,000-word celebration of the stories of Baba Yaga and Koschei and Vasilisa and Ivan(s).

  • The other exchange that I delight in the most is Jukebox, which went live earlier this month (again, I'm still browsing and commenting). I love seeing all the different directions in which people take song lyrics and music videos. Again, I recommend the works. They are fantastic. I am, of course, biased. Even so.

  • After Yuletide, I made two poor fandom decisions, the first of which was to sign up to Worldbuilding Ex despite already feeling burned out & having a tonne of Yuletide admin to catch up on. I can't entirely blame myself because this is a concept I get really excited about, and I had a blast discussing ideas with the mod, and there were amazing works and I got amazing gifts.... It's just that it was unwise for me at that time. I hope next year I manage to be in a better shape after Yuletide.

  • The second poor fandom decision was to take on a pinch hit for Fandom5k, a fic exchange for all fandoms and works of 5k+. I mean, I can sincerely say that it was a fun prompt and I felt I was on my recipient's wavelength, that it offered me the challenge of something I rarely do (write for a TV canon), and that it was satisfying to know I could confidently sketch out a plot that would be long and dense enough and then bring it to fruition. But it was also bad timing and I stressed myself out for a continuous month over the thing.

  • Now I look at my AO3 assignments page and there are NO OPEN ASSIGNMENTS and it is beautiful. Beautiful.

  • ... and while I will not finish a NYR before Crossovering starts, I can at least work on one, and so I will begin to feel on top of things. (Crossovering is awesome! Come play with me! Get your fandom crossovers here! Ahem.)




And in my silence, the song I keep coming back to is Crowded House's How Will You Go, because on their album Woodface, this track ends in over a minute of silence and then a sudden refrain... I'm still here, of course. Looking it up just now, I see it is labelled a bonus track, which makes sense yet never occurred to me before now. I just thought it was .... all the same track. With silence in the middle.



[personal profile] seekingferret, thanks again for the playlist - I really liked "Mah Yedidus" and I grinned to hear it, and the rest comes in shades of appreciative interest. More later.

I also have some gifts from all these exchanges I've taken part in lately. I shall post later about my recent gifts.
genusshrike: Cameron & John from Sarah Connor Chronicles icon (gun)
[personal profile] genusshrike
The first Cyborg movie featured a cyborg, but was not really interested in cyborgs. You could have replaced the cyborg with an ordinary human and it would not have made a difference. She was not even a main character, more of a McGuffin.

Cyborg 2, on the other hand, delivers on the cyborg front, while offering no continuity of characters or world-building with the first movie.

A young Angelina Jolie plays a cyborg intended as a weapon in corporate warfare: the company that built her wants to send her to a meet-up with their competitors, where the bomb inside her will be detonated. A mysterious man who communicates only through screens helps her to escape – along with her combat instructor, who has been looking up the penalties for sexual contact between humans and cyborgs. Together, they must escape to the one place in the world where unlicensed cyborgs can live freely.

Other cyborgs are sent in pursuit, including my favourite character, a vain cyborg assassin whose main concern is preserving his very expensive reconstructed face. There is a sort of robot underground, and a shantytown for those who have been junked. The people involved in this movie were clearly interested in robots! They ask the question, 'can there be love between man and machine?' and they answer, 'hell yes!'

I wouldn't say it's a good movie, or even a consistently entertaining one, but I can definitely appreciate what they were trying to do, and I'm glad we watched it.

(The third movie looks terrible but apparently involves ~cyborg pregnancy~ and also Malcolm McDowell so I think we'll be watching that one as well.)

06/22/17 PHD comic: 'Technically'

Jun. 24th, 2017 08:34 am
[syndicated profile] phd_comics_feed
Piled Higher & Deeper by Jorge Cham
www.phdcomics.com
Click on the title below to read the comic
title: "Technically" - originally published 6/22/2017

For the latest news in PHD Comics, CLICK HERE!

Tumblr "Safe Mode" question

Jun. 24th, 2017 09:01 pm
criticalkink: (Default)
[personal profile] criticalkink
So with the Tumblr "safe mode" thing, criticalkink is listed as NSFW, so you do need to be logged in and have safe mode turned off to see it. Is that going to be an issue for anyone here or does anyone know anyone for whom it would be an issue? My kneejerk workaround is unlisting it as NSFW, but then we get people from the "kink critical" tag complaining, and they're likely to try to get the Tumblr shut down considering how much at least one of them overreacted previously.

All posts on there originate here anyway, and DW certainly doesn't hide things from people (thanks, DW!), but if not being able to access the Tumblr is in any way an issue for anyone, let's talk it through and see if we can find a solution.

Sign ups & mod afk

Jun. 23rd, 2017 03:19 pm
evil_plotbunny: (Default)
[personal profile] evil_plotbunny posting in [community profile] fic_corner
Just a reminder that sign-ups are open. I'll be camping this weekend and may be slow to respond to queries.

Sign-up on AO3. You will need an AO3 account, but their queue is down to less than a day. Please note that you must be logged in to sign-up. Sign-ups will close on June 28th

Fic Corner Tag Set.

Dear Fic Corner Scribbler letters can be found here.

Requests

You must request at least three fandoms, and can request up to ten. You may request between 0 (any) and 10 characters. The exchange is set up to match ANY, not ALL to increase odds of matching. You may not be matched on ALL the characters you request.

By requesting Any, a participant is requesting Any characters on the fandom's nomination list. Do not be that person who requests Any in Fandom F, but writes about specifically wanting Character Z from Fandom F who wasn't nominated.

You may also request Any if you want fics focused on worldbuilding instead of a specific character(s).

Prompt URL: If you want to leave a Dear Fic Corner Scribbler letter for your writer, this is the place to do so.

Description: Optional details are optional, however, if you want to give your writer ideas, this is the place to do it, whether you write a letter or not.

Offers

You must offer a minimum of 3 fandoms, maximum of 10. You may offer up to 10 characters or offer Any.

The bucket list is enabled, so you can offer more than 10 fandoms, but any fandoms in the bucket list default to ANY characters, ANY ratings. More information about making a bucketlist offer (including a lovely diagram) can be found in the Yuletide sign-up instructions.

Don't forget to request/offer fandoms you want. If you're lukewarm about a fandom, don't request it or offer it. Chances are this will be the fandom you receive/are assigned.

Once at least five people have signed up, you'll be able to keep track of current request/offer numbers via the signup summary.

You may edit your sign up form until sign ups close on June 28th.
[syndicated profile] badastronomy_feed

Posted by Phil Plait

Chad Cowan is a storm chaser, and takes astonishing photographs and video of the magnificent weather systems we get here in the middle of the United States.

In late June of 2016, he took time-lapse footage of a supercell forming and growing over Nebraska. It's stunning. Watch:

 

Storm chaser Chad Cowan shot this time-lapse video of a supercell forming and merging with another huge storm system behind it.

 

So what's going on here? The details can be quite complicated — we're talking fluid hydrodynamics here, which is fiendishly complex— but conditions have to be just right for this sort of storm to form.

The video starts with cumulonimbus clouds, the big, puffy, cauliflower clouds that occur when warm, water-laden air rises (called convection). As it does the water condenses to form the visible cloud, and the various updrafts punch upward to form the numerous bumps and bulges.

Then an important event occurs: Underneath the cloud base, the wind shears. This is when a layer of air is moving faster or slower than a layer next to or beneath it. If a layer of air above another is moving faster, it can start a slow horizontal roll or cylinder of air, like a barrel rolling on the ground. But there are also strong updrafts, air moving upward. This can lift one end of the horizontal roll and make it vertical, generating a huge, rotating wall cloud. You can see that under the main part of the cloud.

That's called a mesocyclone, and the whole system is called a supercell. In this case, it's what's called a "low precipitation" or "dry" supercell, because there's not much rainfall from it. Sometimes these dissipate, but not this time: In Cowan's video it merged with another line of storms you can see behind it and to the left, and strengthened.

The intense aquamarine color is not uncommon in these storms, and the exact cause is still unknown. It's likely due to the presence of hail, with red light getting absorbed by the ice so that more green and blue lights gets to us. But it's not clear that's all that's going on.

I've seen a few big systems similar to this, though a very well-organized rotating mesocyclonic wall cloud is still on my "to see" list. They tend to form farther east of where I live; it helps to have wide plains so the wind shear can get picked up by those updrafts. In a sense I'm glad; while weather like this is mind-blowing to see, it's also extremely dangerous to be in.

I asked my friend Marshall Shepherd —who happens to be a meteorologist and in fact was president of the American Meteorological Society in 2013 — about the video, and his thoughts mirrored my own:

The beauty of this storm merger masks the inherent danger it also brings. One of our biggest challenges in meteorology is to developing an observational and modeling understanding of all the physical processes happening at this scale. Such understanding will move the needle further in possibly predicting tornadoes ...

It's sometimes easy to forget, while watching the spellbinding beauty of these systems, how dangerous they can be. This one was reported to spawn a tornado after the merger, but all by themselves the high winds, lightning and torrential rain are threatening enough. Understanding these storms is critical to life in the U.S. Midwest, and I'm glad scientists like Marshall dedicate their careers to doing so.

Tip o' the lens cap to Maksim Kakitsev. You can follow Chad's work on Vimeo, Facebook, and Twitter.

2

Logo Format

Light Logo

Listicle Format

No Markers

Featured Post

Featured

Article Type

News

Is News

Breaking News

Normal

Standout Article

Cover Image Treatment

Image icon chadcowan_supercell.jpg

Hide Related Posts & Comments

[syndicated profile] badastronomy_feed

Posted by Phil Plait

Astronomers have just announced the discovery of a pretty unusual binary system: A white dwarf and a brown dwarf orbiting each other. That's pretty rare, so as cool as that is — and I'll explain why in a sec — even better is how ridiculously close together they orbit: They're separated by a mere 310,000 kilometers, closer than the Moon is to the Earth! And that means they move around each other fast: The intense gravity of the white dwarf tosses the brown dwarf around it at a speed in excess of 100 kilometers per second. That's rapid enough that they make a complete pass around each other every 71 minutes! Yes, minutes.

Yegads.

There are a few really nifty things about this system, so let's take a closer look. But not too close, because you'll get fried. Let me explain.

First, the white dwarf: It's called WD 1202-024, and it was first discovered in a survey of the sky in 2006. At 2700 light-years from Earth, it's pretty faint; the faintest star you can see with your naked eye is 150,000 times brighter!

Like all white dwarfs, it's the remains of a star that was once much like the Sun but ran out of usable hydrogen fuel in its core. It takes billions of years for a star to get to that point, but in this case WD 1202 reached this stage not too long ago, just 50 million years or so in the past. Normally, when a star like that is all by its lonesome, it responds to losing its fuel by expanding its outer layers, swelling to enormous size and cooling down. We call that a red giant. Over time, the outer layers of the star get blown away, exposing the hot core to space. This core is small (around the size of the Earth) and terribly hot, shining a painful white. That's a white dwarf (and you can find out lots more about them in my episode of Crash Course Astronomy about them).

WD 1202

WD1202-024 just looks like a white dwarf sitting out there in space, alone and dim. But it harbors a surprising secret. Credit: Rappaport et al., SDSS

[WD1202-024 just looks like a white dwarf sitting out there in space, alone and dim. But it harbors a surprising secret. Credit: Rappaport et al., SDSS]

But WD 1202 is different. In this new study, the astronomers discovered it's a variable star, changing its brightness in regular, predictable cycles that take a little over an hour. It slowly and subtly brightens and dims, then, for a few minutes each cycle, the light from the star drops precipitously. That's pretty unusual behavior for a white dwarf, and the astronomers quickly figured out what's going: WD 1202 isn't all by its lonesome. It has a companion: a brown dwarf.

Although the names are similar, they couldn't be more different. Brown dwarfs are objects that are too massive to be planets, but not massive enough to ignite fusion in their cores and become proper stars*. In this case, WD 1202's brown dwarf companion has a mass of about 6.6% of the Sun, which is definitely too low for fusion. It's about 67 times Jupiter's mass, so it's way beefier than a planet, too.

Even though it's far more massive than Jupiter, it's not much bigger (brown dwarfs are weird that way; their cores are very dense and take on odd properties, such that as you add mass to them they actually shrink). But it's still much larger then WD 1202, probably 4 or 5 times wider.

And that's why the brightness of the system changes. Get this: The subtle variations are caused by the brown dwarf itself as it goes around the smaller dwarf. We're seeing its phases!

[The WD 1202-024 light curve is caused by the phases we see of the brown dwarf orbiting the white dwarf, plus a bonus eclipse. Credit: Rappaport, et al. / Bishop's University]

This is just like the Moon, where we see it go through its phase of new (when we only see the dark half), first quarter, full (when we see it fully lit by the Sun), then last quarter, then new again.

But in the case of the brown dwarf we're seeing phases, not because it's reflecting light from WD 1202, but because it's heated to incandescence by it!

The white dwarf is small, but it's furiously hot, about 22,400° C. The side of the brown dwarf facing the white dwarf is heated to glowing. When it's on the other side of the WD 1202 from us we see it full. A quarter of an orbit (about 69 minutes) later it's half full, then another quarter of an orbit after that the unlit side is facing us, so the system is dimmer. After that we start to see the lit side again until it's full, and the cycle repeats.

But there's more. Because the brown dwarf is so much bigger, when it's "new" it actually gets in the way of the white dwarf and blocks its light from us. That's why the brightness drops so much every 71 minutes!

WD 1202 light curve

[The light curve of the binary (the change in brightness over time). The red line is a model that includes the phases of the brown dwarf and the eclipse; the black line is the observations (exposure times are about 30 minutes, so the eclipse isn't seen), and the blue line is the model mathematically fit to the observations (including the exposure time fuzzing out the eclipse). Credit: Rappaport et al. / Bishop's University]

I love just this part of the story. That brown dwarf is far too faint and close to WD 1202 to see it separately, but we can infer its existence because of its phases even though it's 27 quadrillion kilometers away. How about that?

But there's more, and it's also wondrous. Get this: The brown dwarf was, for quite some time, literally inside WD 1202!

Let's rewind the clock back to when WD 1202 was a regular star, about to run out of hydrogen fuel in its core. Back then, the brown dwarf was farther out, probably something like 50 million kilometers out (or half the distance from the Earth to the Sun), well separated.

But then WD 1202 expanded into a red giant. These kinds of stars get really big, easily spanning a hundred million kilometers across, sometimes more than twice that. That's bigger than the orbital distance of the brown dwarf, so when the primary expanded, it engulfed the brown dwarf.

Yet it persisted. That's because when it expands, the density of the gas in the red giant's outer layers dropped hugely. The lower density is what saved the brown dwarf from destruction. It would've been heated a lot by the star around it, and the drag from plowing through the material would have shrunk its orbit. As it got closer it would have orbited faster than the red giant rotated, too, so the companion acted like an egg beater, stirring up the primaries outer layers.

That can give the gas so much energy that they are expelled even more rapidly. When this violent period in the binary's life was over, what was left was the white dwarf with the companion brown dwarf in its tight orbit. Judging from what we know about the physics of such events, and the temperature of the white dwarf (they cool over time, giving us a measure of their age) this happened about 50 million years ago.

That's seriously cool. And yet there's one more thing.

[Artist's drawing of the RS Ophiuchi system, a similar one to what WD 1202 will be like in a couple of hundred million years. Credit: David Hardy & PPARC]

The gravity of the white dwarf is impressive. When you squeeze half the mass of the Sun into a ball about twice the size of the Earth, it's phenomenally dense. The surface gravity is tens of thousands times stronger than Earth's. If you stood on its surface, you'd weigh thousands of tons. Oof.

As it happens, the brown dwarf is orbiting so close to WD 1202 that its gravity is felt very strongly indeed. Over time, even now, the brown dwarf is slowly spiraling in, getting closer to the white dwarf as they emit gravitational radiation (for more about that, read this article about gravitational waves). The astronomers who observed the system calculate that in about 250 million years, the brown dwarf will get so close to the primary that the white dwarf's gravity will start to draw material off the companion!

This material will pile up on the white dwarf and get squeezed excruciatingly hard by the intense gravity. When there's enough, it will undergo sudden and catastrophic hydrogen fusion, exploding literally like a thermonuclear bomb. This explosion is very energetic, and the system will dramatically flare in brightness. Then it will fade as the material blown off cools and blows away … and then the cycle will star again.

This kind of object is called a cataclysmic variable, or CV, and we know of quite a few. We also know of a few pre-CV systems, but this one has the shortest period of any known, which means it's the closest we know of that will become a proper CV in the future.

So, as amazing as this system's history is, and is now, its future will still hold plenty of wonder. As long as you stand a bit back from it. Cataclysmic variable are given that name for a very good reason.

This is one of those science stories where I dig every piece of it. It's got quite a bit of the stuff I love: stellar evolution, weird objects, cool geometry, and it ends quite literally with a bang.

The Universe is a pretty interesting and astonishing place, if you look at it carefully enough.

*Some people call them "failed stars", which is a term I don't like, for two reasons: They aren't stars at all, they're their own class of object; and why call them that when you could be more positive and call them really overachieving planets?

[N.B.: In the title of this post, I refer to the brown dwarf as a star. As I describe in the text, technically it isn't. But in a title I have to be brief, and if I said, "... one of the components..." it would read oddly, and distract from the main point. I struggled with this, to be honest, trying to figure out a good way to say this while still be being accurate. It was surprisingly difficult (note that I never refer to this as a "binary star" in the text, but instead call it a system or a binary system). Being scrupulously accurate in terminology can make things harder on the reader sometimes, and in this case I decided to ease up on the pedantry to allow an easier understanding. If you agree or disagree, I'd be curious to hear your opinion. There's probably an interesting article all by istelf on this topic!]

10

Logo Format

Light Logo

Listicle Format

No Markers

Featured Post

Featured

Article Type

News

Is News

Breaking News

Normal

Standout Article

Cover Image Treatment

Image icon whitedwarf_planet.jpg

Hide Related Posts & Comments

[personal profile] sabotabby is focused

Jun. 22nd, 2017 09:01 am
rydra_wong: dreamsheep with spork and "SheepSpork" logo; no, it wouldn't make any more sense if you saw it  (dreamwidth -- sheepspork)
[personal profile] rydra_wong posting in [community profile] metaquotes
Possums and communism are basically my whole life.


Context is locked; QWP.

(no subject)

Jun. 21st, 2017 08:12 pm
[syndicated profile] yarn_harlot_feed

Posted by Stephanie Pearl-McPhee

Monday was a stinking slag heap of a day. Monday’s scene was scrambled, it couldn’t get itself together, and despite noble, persistent and good-natured attempts by yours truly to bring it around and call it to its higher self, Monday didn’t even try to work things out with me. I tried with Monday, I really did. I tried going for a training ride – it’s been so hard to find the time and energy, only to get a stinking flat tire. (Which I changed, with no amount of struggling for good humour.)  I trudged through it, attempting to charm it into submission, but Monday proved too much for me, and after spending the evening’s knitting time trying to untangle a ball of yarn that had contorted itself into something that looked like it had been in a toddler’s toy chest for a week,  I fell into bed that night thinking the best thing an optimistic person can after a day that’s clearly out to get them, which was “well, at least it’s over.”

Tuesday? Tuesday wasn’t as bad as Monday, but let’s be clear, it lacked the joie de vivre and decent good sense that any day attempting to follow a train-wreck of a Monday should have had. Tuesday didn’t even try.  I gave up on Tuesday last night when it rained on me last night and the porch roof leaked.

Today? Today is, rather literally, sunshine and roses.  I went for a training ride by myself, and it was nothing short of lovely. Not too hot, not too cold, very sunny but I didn’t get a sunburn, my inbox is almost sorta kinda under control, and I am finally ready to start the edging on this baby blanket.

blanketlight2 2017-06-21

The chart I devised even works, and I have a clever idea for the corners that I think will work, though I’m not far enough off from Monday and Tuesday’s pale curse to go so far as to say I’m confident. My jeans fit just right, and tonight I’m having dinner (it’s Joe’s turn to arrange it) and a cuddle with Elliot Tupper, and he has learned to smile and has the beginnings of a clumsy laugh,  and does his best to pretend he likes me best. (Joe will argue and say it’s him that’s the favourite, and even that charms me.)

Happy Summer Solstice, my friends (except for Cameron and other knitters in the Southern hemisphere – for them it’s one of my favourite days, the Winter Solstice. Light a candle. As of today, the light is on it’s way back to you.) Tonight we’ll sit in the garden, ignore the weeds, and marvel at how long it stays light.

How’s your day?

Profile

labellementeuse: a girl sits at a desk in front of a window, chewing a pencil (Default)
worryingly jolly batman

February 2017

S M T W T F S
   1234
567891011
12131415161718
1920212223 2425
262728    

Most Popular Tags

Style Credit

Expand Cut Tags

No cut tags
Page generated Jun. 27th, 2017 05:12 am
Powered by Dreamwidth Studios