Posted by Phil Plait

A new observation of the bright star Betelgeuse shows it's … odd.

[Credit: ALMA (ESO/NAOJ/NRAO)/E. O’Gorman/P. Kervella]

You can see it in that image (much bigger versions are available, too). The orange color isn't real; the observations were made using the Atacama Large Millimeter/Submillimeter Array (ALMA), which observes light way outside the color range our eyes can see. But the bright spot to the upper left is real, as is the gigantic lump on the left side, too. But here's the thing: That lump isn't really a lump, at least not a physical protrusion in the side of the star. It's actually a place where the star is warmer and denser, making it look like a lump.

I know, that's weird. Let me explain.

First, Betelgeuse is a red supergiant, a star much more massive than the Sun (about 20 times the Sun's mass) and nearing the end of its life. When a star like that runs out of available hydrogen in its core to fuse into helium, the core heats up. The gas above the core responds by expanding (just like a hot air balloon; when you heat a gas it expands). Furthermore, Betelgeuse is already on the next step, fusing helium into carbon and oxygen. That creates a huge amount of energy that gets dumped into the outer layers. When that happens a star's size increases hugely; depending on how you measure it Betelgeuse is about a thousand times wider than the Sun!

Normally, stars are far too small to see them as anything other than points of light. But Betelgeuse is so big that our most powerful telescopes can resolve it into a disk. The ALMA image shows it to be about 0.1 arcseconds wide. Arcseconds are an angular measure; there are 60 arcseconds to an arcminute, and 60 arcminutes to a degree. The Moon appears in the sky to be 0.5 degrees = 30 arcminutes = 1800 arcseconds across. That's 18,000 times wider than Betelgeuse!

So just seeing Betelgeuse at all as a disk in these images is pretty amazing. But it gets better.

When a massive star expands into a red supergiant, counterintuitively, despite the extra energy, the gas cools: That same energy is spread out over a lot more volume, so each cubic centimeter of the star has less energy in it. When the outer layer cools it goes from being blue-white hot to reddish, dropping to a temperature of a few thousand degrees Celsius, cooler than the Sun.

I described how this works in my episode of Crash Course Astronomy: High Mass Stars (at about the 2:30 mark):

Betelgeuse doesn't have an actual surface. It's a gas, and a pretty rarefied one at that. The density deep inside it is quite high, but by the time you get out into that outer part the density can be so low it's pretty much a hot vacuum.

So a funny thing happens when you look at it. The kind of light you see from the star depends on the density and the temperature of the gas emitting it. Deep down, it's hot and dense, and the light is bluer – a wavelength of a few hundred billionths of a meter. Up near the top, the gas is cooler and thinner, and is redder, with a wavelength twice as long. Gas farther out from the center emits even longer wavelength light, with a wavelength around a millimeter or so.

That’s the kind of light ALMA is sensitive to. So what you're seeing isn't really the surface of Betelgeuse — which it doesn't have anyway — but just the gas in it that emits at that wavelength. The size you measure for a star depends on what kind of light you're looking at!

This is where that lump comes in. At a certain distance from the center of Betelgeuse, the gas is the right temperature and density to emit the light ALMA sees. Outside of that it's cooler, and doesn't emit that light, so it looks black. There is still gas there, but we just can't see it in the ALMA image. However, for some reason, in that one spot on the edge of the star there is some gas still warm and dense enough to emit millimeter light, and so we see it in the ALMA image as a lump, a local patch of gas warmer (and/or denser) than the gas around it.

That bright spot stretching across the upper left of the star may be the same sort of phenomenon as the lump, but we see it against the disk of the star, so it looks like a bright spot.

So what's causing this? It's not clear. It may be magnetic in origin. The Sun has a pretty strong and complicated magnetic field, and that can cause all sorts of odd features we can see. Betelgeuse has strong convection — hot blobs of gas rising from the interior, like water boiling in a pan — and we know that these blobs can have their own embedded magnetic field (the Sun does the same sort of thing). It may be we're seeing the top of a strong convection cell in Betelgeuse, with the gas heated by the magnetic field it carries.

I know this may seem a little esoteric, but it's actually pretty important. For one thing, we know that red supergiant stars blow tremendous winds of gas, like a super solar wind (Betelgeuse has a wind a million times stronger than the Sun's!). But we don't really understand the mechanism behind it. Magnetic fields may be important there, so studying Betelgeuse's upper atmosphere could lead to insight there.

Also, stars like Betelgeuse do one more thing at the ends of their lives: They explode. Like, supernova explode, sending huge amounts of gas several times the mass of the Sun screaming outward at a significant fraction of the speed of light! Betelgeuse is about 8 million years old, and may only have about 100,000 years left before it goes bye bye. At a distance of 650 light years or so, it's probably too far from us to physically impact us, but it'll be bright when it explodes, about as bright as the full Moon. You'll be able to see it in the daytime.

These explosions create the heavy elements we need to live: The iron in our blood, for example, came from a star that blew up long before the Sun was born. Studying Betelgeuse gives us insight into this mechanism, which in turn is critical for our being here at all to study it!

Beyond that rather philosophical direction of thought, Betelgeuse is just amazing to observe. In 2013, astronomers observed that it had blown out an arc of gas as big as our solar system! It's also traveling through space, and the gas blowing away from the star will soon (well, in 5,000 years) hit a sheet of gas that will distort and interact with the star's wind. That should make for pretty pictures.

And, as you may know, Betelgeuse marks the right shoulder of the constellation Orion, and is bright enough that we can actually see its reddish color with the naked eye. I like showing it to people through my telescope when I can; the color is amazing, and it’s so bright it's like a ruddy gem in the eyepiece.

And I like knowing that as beautiful as it is by eye, what we see is just one small bit of what Betelgeuse really is. If it had a surface, we'd barely be scratching it.

[The image at the top of this post is Orion by Rogelio Bernal Andreo; Betelgeuse is the bright orange star at the upper right. This is the best image of the constellation I have ever seen, and you can buy a print of it.]

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Posted by Phil Plait

There’s beauty in science. Let me show you.

Have you ever seen a circular rainbow? It’s technically possible, though you have to have special circumstances for it, like being in an airplane, or in a tower high above the ground.

Or you can cheat. Not in an unfair way like using Photoshop, but by being at the right place at the right time, and reflecting on the scenery a bit.

Literally.

[A circular rainbow... due to a reflection in water. Credit: Göran Strand]

 

That lovely picture is by Swedish astrophotographer Göran Strand, who happened to catch the optical phenomenon in Vansbro, Sweden on June 24, 2017, just as the Sun was setting.

The timing was critical for this shot, as much so as the still water needed to reflect it. Rainbows are due to sunlight getting reflected off the backs of water droplets in the air. Due to the geometry of that reflection, you only see the rainbow light sent back to you from drops that are about 42° away from the point in the sky opposite the Sun.

 

If you have a hard time picturing that, then think of it this way: Picture the Sun low in the sky - say, 10° above the horizon (roughly the width of your fist held at arm’s length). Now. turn around so you’re facing in exactly the opposite direction. The point in the sky opposite the Sun —the anti-solar point— is now in the direction you’re facing, but 10° below the horizon.

The rainbow is centered on that point, but it makes a circle 42° in radius, roughly an eighth of the way around the horizon. If the Sun is higher in the sky, the anti-solar point is lower, and vice-versa. So if the Sun is directly on the horizon, the anti-solar point is. too.

If the area of the sky around the anti-solar point has water droplets in it —say, from a rainstorm in that direction, or due to a sprinkler or waterfall shooting water into the sky— and the Sun can shine on it. then you’ll get a rainbow that is exactly a semicircle, half a circle stretching up 42° into the sky.

And that’s what Göran did! The rainbow is very nearly a perfect semicircle, and the reflection in the water makes it a complete circle. Amazing.

But there’s more! Light bends when it enters and exits the water droplet (what we call refraction). But red light refracts less than blue, so you only see it from water droplets a little farther out from the anti-solar than blue. This spreads the colors of the sunlight out. Not only that, but sometimes. the light can get reflected inside the water droplet twice, making a secondary rainbow farther out than the primary one. You can see this a bit in Göran’s photo (to the upper right), but it’s faint. When there’s enough light the secondary is brighter, and you can see the colors are reversed! That’s because the second reflection in the droplet reverses the colors, just like looking in a mirror reflected in another mirror reverses the first mirror’s reversal.

 

One final thing to see in Göran’s shot: right in the center. you can see rays of light and shadow converging. Those are called crepuscular rays, what most people call sunbeams. They’re really just sunlight shining through clouds or past mountains, contrasted with the part of the sky shadowed by those same obstacles. They appear to diverge away from the Sun, but they converge on the anti-solar point. And this part really throws people: They’re parallel!

Yes, seriously. They only appear to converge or diverge due to perspective, the same way railroad tracks appear to converge at the vanishing point, on the horizon.

I could go on and on, taking about the supernumerary arcs, Alexander’s dark band, and more. I love the optical effects of rainbows, and I never get tired of them. And it goes to show you: When it comes to science, you’re soaking in it. It’s literally everywhere, all around you, affecting everything you see and do in life.

Sometimes, you just have to notice it. And when you do, you’ll find there’s science in beauty…and you’ll realize you’ve come full circle.

You can catch Göran and his wonderful photographs on Twitter, Instagram, or at his website.

 

[Droplet image credit: Wikipedia/KES47, adapted by Phil Plait]

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nou: The word "kake" in a white monospaced font on a black background (Default)

I only managed one attempt at the June challenge this year: a modified version of Theme II.(a): Lines.

The full version of this challenge involves starting at a railway terminal and walking outwards from the terminus, following one of the railway lines as closely as possible. I’ve been doing this in stages from West Croydon Station to London Bridge Station, and this month I did a new stage.

I was originally going to walk from Tulse Hill to East Dulwich, but my lungs were playing up so I stopped at North Dulwich; i.e. I only walked one stop. Here’s a map showing my route so far (plus the bit I intended to but didn’t walk, which will be done next time), and here’s a photoset including all stages so far.

I photographed quite a lot of railway bridge identifiers on this one, since [personal profile] secretlondon and I are collecting them, and railway line walks are a very good source. My favourite photo is the one below, showing the premises of a “Fibrous Plaster Specialists”.

A view through a square brick-lined tunnel to an open passageway and buildings at the far end.  A dilapidated sign on the left wall reads “19a / E J Harman & Co Ltd / Fibrous Plaster Specialists / 19a Birkbeck Hill SE21 8JS”.

Someone came out just after I took it and asked me why I was taking photos. They seemed a bit offended by my use of the phrase “old sign”, oops. They were very keen to make it clear that the business is still going!

sonia: Presence After Trauma cover (Presence cover)
Even if we missed out on learning how to be calm as babies, it is not too late for our nervous systems to learn about rest and regulation as adults.
Find Calm: Practice Rest and Regulation

New book response at Curious, Healing. Have you read this? Comments welcome!
Video on co-regulation
Bonnie Badenoch, psychotherapist and professor of interpersonal neurobiology, warmly explains co-regulation and polyvagal theory in her video How to Feel Safe in Your Relationship. Thanks to Donna Norfolk for the link.

Curious, Healing is a blog, and you're welcome to comment there or here about the books. The articles don't have a comment section. You're welcome to comment here or send me email with any thoughts.

If you want the monthly newsletter in your inbox, along with news about my practice, you can subscribe here.

Neither Wolf Nor Dog

Jun. 27th, 2017 06:33 pm[personal profile] sonia
sonia: Quilted wall-hanging (Default)
Went to see Neither Wolf Nor Dog at Vancouver's old time Kiggins Theater. (Summary linked, and quoted below.)

Can't remember the last time I saw a movie, in a theater or out of it. This one was sparsely attended, and therefore fragrance-free enough for me, yay.

This movie is worth seeing. It is much more up close and personal than the summary implies. The Native Americans are saying, "Look at me! Look at us! We are PEOPLE. These atrocities happened to me, to my family. See us!" The white guy is saying "privilegeprivilegeprivilege oh wait maybe I'll see you a little bit."

I'm so glad the Native American folks got to tell their stories and show their lives and landscapes. I hate that the story centers on the white guy's narrative. He's the one who changes as the Native Americans instruct him.

The cinematography and secondary part acting are bare-bones. For me, that emphasized that these are real people, this really happened, this is the landscape where it happened.

Summary )

what a time to be alive

Jun. 27th, 2017 06:11 pm[personal profile] waketosleep posting in [community profile] 2017revival
waketosleep: Buster Bluth with a watermelon under his shirt, posed seductively (AD - busty buster)
*walks in late* Hello, new neighbours! Please be my friend! Wait, don't leave!

Name: Mer/waketosleep (my old LJ was stripedpetunia)
Age: 29 (for three years now)
Location: Canada
Tumblr/Goodreads/IG/etc: IG is alarmingllamas and a great place to see pointless photos of my cat; I'm active on twitter as @alarmallama and my AO3 handle is waketosleep.

Describe yourself in five sentences or less: I'm a cis bi woman going into my second year of law school, because my last career decision was very regrettable, and I was diagnosed with ADHD a year and a half ago so that's been an exciting combination. I've been writing in fandom for ~15 years but between the ADHD and the law school and how much of your life can be swallowed up by trying to pay bills, I don't write as often as I used to. My other interests include TV shows, knitting and crochet, the CFL (I'm a Stamps fan), Canadian politics, cola bottle gummy candy, linguistics (that's the bachelor's degree--syntax and SLA what uppp) and video games, but of course that list is far from exhaustive because my interest is easily captured by new and shiny things. I'm on tenterhooks waiting to see who the new Chief Justice of the SCC will be (I'm hoping Justice Abella). That's what law school does to you; don't go to law school.

Top 5 Fandoms:
When it comes to creative contributions such as fic, in no specific order:
- Star Wars
- GenKill
- Marvel
- Star Trek AOS -- I'm not super engaged with this fandom anymore but I think it's the one I'm most associated with, fic-wise
- Mass Effect

I am enthusiastic and will talk your face off about a lot of other TV/games/books/etc, but my actual online fandom engagement is more limited to the above things and whatever else I've written fic for in the last 3-4 years.

I mostly post about: I've been on DW since it launched and spurred one of the first major LJ emigrations but haven't posted much since Tumblr killed journaling and my circle turned to crickets. I'd like to try and get back into it. Expect AO3 shares of new fic I write and random posts about whatever media I'm watching, with less frequent, slightly more personal posts about things like life updates/craft projects/complaining about law school and law students and the law. Some of those I lock, depending on their content. I'm also open to discussing my adventures with ADHD.

My last three posts were about: *checks* ...A Star Wars fic, a Six of Crows fic and a roundup of good things that happened to me in 2016.

How often do you post? How about commenting? I've never been a daily poster but I'm going to try to up the ante from twice a year. I'll set a goal for weekly. I respond to comments on my posts and I like to comment on your posts when I have something to say. Comment-thread conversations are one of the things I miss most about journaling.

Posted by Phil Plait

I was recently contacted by a radio show called “Texas Standard” for an interview. Not long before, astronomers announced they had found an additional 200 exoplanets, worlds orbiting other stars, including 10 that were about the size of Earth, adding to the more than 2,000 known exoplanets already discovered. The host of the radio show, David Brown, wanted to look past the specific news a bit and ask a less proximate question: Why should we care?

This is, in fact, an excellent question. We are inundated with news of all kinds, and science news can get lost in the noise, especially when it’s incremental news, not a major new discovery but something that just adds to and reinforces what’s already known.

You can listen to the interview at the “Texas Standard” site; it’s relatively brief.

I want to talk about this a little more, because the interview was abbreviated and this is an important topic.

Why should we care about this news, or indeed any science news? As I said in the interview, it’s because we’re not automatons, trudging along our dreary lives, counting the gray minutes until we die. We are multidimensional beings, capable of seeing and doing so much more, wanting to experience wonder and joy, and curious about the Universe around us.

When we find a new collection of exoplanets, for example, it’s more than just tossing a handful of dusty old data onto a now-slightly-bigger pile. You have to get past the hype and understand what we’re doing here: Kepler is designed to look at a small patch of the sky, one you could easily cover with your thumb held at arm’s length. It looks at 150,000 stars in that patch, and over four years has found well over 2,000 planets. But there are hundreds of billions of stars in the galaxy, a million times as many as Kepler is studying.

Statistically speaking, for every planet Kepler finds, there are a million more in the galaxy waiting to be discovered.

This is profound knowledge, the sort of thing that fills the soul, opens the mind, makes us crave to understand more. This alone is reason enough to study the heavens. It stirs our passion and is no different than the drive that motivates us to create great works of art, or to ponder the deepest of philosophical questions.

There is a part of us that seeks to know more about what’s outside of us. When we gaze upward, when we train the results of our centuries-long technological and scientific ambition on the heavens, we can find those answers. It satisfies, at least in part, that itch to know more.

But there’s more to it than that. These philosophies, these desires, do not exist in a vacuum. For some, this sort of exploration demands a more materialistic impetus.

For them, note then that motivated self-interest plays into this as well. We are to the best of our knowledge the first technological civilization on this planet, and we’ve spread to every place on it, and even, in a limited sense, above it. The technology we developed to allow this is interacting with the Earth, changing its surface and atmosphere and oceans, and some of these changes are not necessarily to our benefit. We’re running a massive global experiment with no control groups.

By sending up satellites to look down on Earth we’ve discovered these changes and have been able to deal with some of them. But we don’t fully understand the way our planet works. We study it intensely, but it is the only sample of a planet like ours we can study. It would be extremely useful to have more, so that we can compare and contrast our home world’s behavior with theirs. By looking outward we can find these other planets, see how they work, and then learn more about our own.

These aren’t just words. These are actual deeds, things that we really and truly are doing and learning by studying other worlds. We’re trying to answer the biggest questions there are. Why are things this way and not another way? Why are we here? What lies ahead? But we are also hoping to answer more immediate questions: How are we changing our planet? How quickly are we changing it? What can we do to prevent these changes becoming toxic?

Certainly not all these issues will be solved, by searching for exoplanets or otherwise. But the same desire and the same means to do so —science— are by far the best paths we can take to lead to the answers we seek.

By looking outward, we look inward.

One more thing. In the interview, the host then said an interesting thing with respect to this new exoplanet finding: If you find a grain of sand, and then even another hundred grains of sand ... if you know there are billions out there, then who cares?

Ironically, this analogy does not show how these discoveries inure us to this news. It shows the exact opposite.

Imagine you’ve lived somewhere isolated, say deep in a forest. You’ve never seen a grain of sand, but you’ve wondered if they exist. Then you find one. Sand is real! That’s a terribly important discovery, and has profound implications. And then you find another one, and the next one, and the next one, and a new revelation dawns: Sand is common. And as you make a pile of them you find some are clear, some translucent, some green, some yellow, some black. They come in different sizes and shapes, and are composed of different materials. What is this telling you?

So you go exploring, and find more sand the more you look. You see more, and more, and then, breaking through the trees, you see to your utter amazement a beach stretching out before you, something you could only dream of before.

But even that is nothing compared to what lies beyond: an ocean, something you could not have even conceived of. It is beautiful, dark, vast, sweeping, its motion beguiling and enthralling. And even as you see it, you realize you’re only seeing the surface. What lies beneath?

All this because you found a grain of sand, and decided to look for more.

That is why we look for exoplanets. And that is why we do science.

[Top image: Hubble's view toward the center of our galaxy. 150,000 stars are visible here. How many have planets? Credit: NASA, ESA, K. Sahu (STScI) and the SWEEPS science team]

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no totoro

Jun. 26th, 2017 08:35 pm[personal profile] sasha_feather
sasha_feather: horses grazing on a hill with thunderheads (horses and lightning)
Jesse and I went to go see "My Neighbor Totoro" at the theater. We get there and it's very nearly sold out; we get the last two tickets that someone was refunding. Neither of us are quite trained into the new system where you are supposed to always buy your tickets ahead of time, having lived our whole lives as spontaneous movie-goers.

I get some snacks and we settle into our seats. The movie starts, the cute song and the little girl walking. Soon we realize, we are seeing the Japanese version with no subtitles. Someone alerts the staff and the movie plays on. I'm happy to watch it this way-- the story is very simple and to me, not understanding the words only plays into the dream-like quality of Miyazaki movies. But not long into it, the movie pauses and the manager comes in, to apologize. He says that they got the wrong version, and they will be playing the English dubbed version. Some people in the audience object. My friend a row below us calls out for people to clap if they want the dubbed version vs. if they want the Japanese version. It's about evenly split.

Well, they must have decided to do the dubbed version because they stopped the film. We decided to leave and get our refund.

Anyways, that is our Totoro story!

More Plans Than Events

Jun. 26th, 2017 09:01 pm[personal profile] l33tminion
l33tminion: (Overwork)
Last week was pretty quiet. This past weekend, too. Though we did go out for soup dumplings with Ingress friends on Sunday.

Julie's startup-founding work continues to progress.

It's the turn of the quarter, so a lot of reflection and planning at work. Things ebb and flow. First quarter was pretty great, this quarter was all right. But I'm excited about the next. For some reason, I'm at least briefly in charge of planning the quarterly goals for my group, which is an interesting opportunity (though I wish some of the related deadlines had been a little better communicated).

I want to get back to writing on my essay blog at some point, but my writing is very slow even for lighter stuff like this.

What else? My parents will be in Boston later this week, and we're going up to Sandy Island Camp next week. That should be fun. Haven't picked out which books I'll bring yet, but I certainly have a lot on my queue.

(no subject)

Jun. 26th, 2017 09:25 am[personal profile] seekingferret
seekingferret: Photo of me with my 2012 Purim beard, with stripes shaven into it. (Default)
At the end of the story of Korach ben Itzhar, the cousin of Moses who leads a strange rebellion in Numbers 16, Moses says

Numbers 16:29-30If these men die the common death of all men, and be visited after the visitation of all men, then the LORD hath not sent Me. But if the LORD make a new thing, and the ground open her mouth, and swallow them up, with all that appertain unto them, and they go down alive into the pit, then ye shall understand that these men have despised the LORD.


'Make a new thing' is a doubled use of the same Hebrew root letters, and that root is the root used in Genesis 1 to describe God's Creation of the world, so trying to preserve some of the sense of the Hebrew we might render it 'Create a creation'. Which is terribly infelicitous, so.

There is a debate among the more philosophical commentators about the nature of miracles. Rambam holds that God set in motion the natural laws of the world- physics, in a nut shell, and then because God is the Unity at the center of creation, God is able to alter those natural laws to effectuate something outside of them. Ramban, instead, holds that all of creation is constantly and miraculously being instantiated by God and that what seem to be miraculous violations of the natural laws of physics are just naturally within God's power. Both Rambam and Ramban are incredibly subtle and complicated thinkers and it's hard to say what either meant. It's possible this is not a debate and that they're truly in agreement. I do not claim to understand their teachings, which is why this post. But let's assume this is a debate as at least a starting axiom.

There's a third position, one which is at the same time even more naturalistic than Rambam and less, or which may be what Rambam is actually saying, I'm not sure. And it derives from this moment in the story of Korach.

Pirkei Avot 5:6 : Ten things were created on the eve of the [first] Shabbat at twilight. And these are they: The mouth of the earth [that swallowed Korach in Numbers 16:32]; and the mouth of the well [that accompanied the Israelites in the wilderness in Numbers 21:17]; and the mouth of the donkey [that spoke to Bilaam in Numbers 22:28–30]; and the rainbow [that served as a covenant after the flood in Genesis 9:13]; and the manna [that God provided the Israelites in the wilderness in Exodus 16:4–21]; and the staff [of Moshe]; and the shamir (the worm that helped build the Temple without metal tools); and the letters; and the writing; and the tablets [all of the latter three, of the Ten Commandments]. And some say, also the destructive spirits, and the burial place of Moshe, our teacher, and the ram of Abraham, our father. And some say, also the [first human-made] tongs, made with [Divine] tongs.



This is a really complicated Mishna that I don't understand at all, but it seems clear from the fact that the first item on the list is the mouth of the Earth that it's the phrase "Create a creation" that is the source for this logic. (I don't have the sources for all of the other things in this Mishna. I think the fact that the other two mouths are mentioned sbusequently suggests that the Earth-mouth is the source for all three of those. And I'm pretty sure there's no Torah source for the bit at the end about tongs, which is why it's just part of the 'and some say'... all that is purely Midrash Aggada) The Mishna is saying that Moses asked God to invoke a miracle of creation and this mouth that had been created at Creation and set up to swallow Korach swallowed up Korach. And it raises a lot of questions. It seems to be a response to this question of the nature of miracles, and its answer is in one sense more naturalistic than the Rambam: Not only is the world run according to natural laws set in motion at creation, but even things that apparently work outside of the laws of nature are actually naturally set in motion at creation as part of a special step in creation that took place Bein Hashmashot of Erev Shabbat.

Yet this is a hugely problematic theory for Jews because it seems to propose a completely deterministic universe where an intervention like the Earth swallowing up Korach for sinning against Moses and God can be preprogrammed as part of creation. If this is the case, where is free will? Where is Korach's ability to choose on his own whether or not to sin, if this preprogrammed miracle Earth-mouth was created as part of the Creation of the World?

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

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Thought for the Day

Jun. 25th, 2017 10:57 pm[personal profile] bcholmes
bcholmes: I was just a brain in a jar (brain thoughts)

Lately I’ve found myself spending too much time arguing with “allies.” Whether it’s explaining to them, as a black gay man, why racism in the Gayborhood is a serious issue or why nondiscrimination laws should be statewide, it feels as though I’m having to defend myself to those who should be advocating by my side. What I have realized is that too many allies conduct themselves as service providers: They show up only when there’s an immediate need, they require me to explain the problem again and again, and they may or may not actually fix anything.

In other words, allies are more trouble than they’re worth.

— Ernest Owens, “Why I’m Giving Up on ‘Allies'”

Mirrored from Under the Beret.

Flaneurs bus challenge I. (c) - 2017-06-22

Jun. 25th, 2017 07:37 pm[personal profile] bob posting in [community profile] flaneurs
bob: (beard)
Hello,
As is customary I did Flaneurs bus challenge I. (c) from the same stop as before with an unchanging n of 6.
In exciting news I managed to finally cross the river and in fact ended up at Tottenham Hale. I covered about 30 miles on buses on the hottest day of the year. The routemasters were hellish.


* Map
* Google Photos or Flick Photos depending on what you prefer. Includes lots of video.
* Twitter thread


I'm currently uploading the videos to youtube and may make a longer video of them.
Talking of which I often post videos of my bus journeys on my youtube channel

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