quarta-feira, agosto 01, 2018

Opposable Thumbs: “The Calculating Stars” by Mary Robinette Kowal




“There is nothing to see but that vast blackness. Intellectually, I know that we’ve passed into the dark side of the Earth. We slide into her shadow and then magic fills the sky. The stars come out. Millions of them in crisp, vivid splendor. These are not the stars that I remember from before the Meteor. These are clear and steady, without an atmosphere to make them twinkle. Do you remember the first time you saw the stars again? I am sitting in a capsule, on way my to the moon.”


In “The Calculating Stars” by Mary Robinette Kowal

I remember the one called "Duck and Cover". If I remember correctly, the instructions included:

1. Fill the bath with water
2. Take a door off it's hinges and prop it length-ways against an internal wall
3. Cover the door with a mattress
5. Get the family under the door.
6. Crouch down on the floor
7. Put your head between your legs
8. Kiss your arse goodbye

Even at 10 I thought that wouldn't help much...and it was bloody nonsense. How is an entire family going to take a bath before the four minute warning is up?

We're statistically overdue a large near earth object colliding with earth. Overdue in this context is wildly variable - range from 1 day to several hundred thousands of years depending on how you choose to measure. The main point is that if this does occur in the near future there is no technology available that would give a reasonable chance to even detect the damn thing. To paraphrase Doug Adams - space is big, really fucking big. We have about the same chance of seeing a significantly sized object inbound to us as a man sitting in his living room in London has of seeing a fly alighting from a randomly chosen dog turd in Moscow. Next step - assume that we manage to see this in advance and have reasonable notice. We haven't been beyond near earth orbit for 40 years. How would we get to this object and what would be brought to bear to deflect it?

I guess that educating people and getting them not to stand by a window may be advisable. In the same spirit I'm going to start training pedestrians to avoid damage from cars by hurling handfuls of peas at them from 100 yards. Knowing with certainty that a NEO will impact 30 years ahead of time, and knowing exactly how to nudge it to avoid that are unlikely in most cases -- even assuming a purely Newtonian world with perfect measurement of an object's current mass and trajectory. Except for contrived cases, the n-body motion problem in that world for n > 2 has no closed solutions. The numerical methods applied to it have some inherent and unavoidable error. Relativistic effects, although negligible, probably cannot be neglected if such precision so far ahead of time is to be achieved, further complicating the computation. And of course in the real world, measurements aren't exact. This is why this NEO work deals with probabilities, not certainties, and why (along with political difficulties) I suspect that the lead time will be shorter than 30 years and/or big bombs will be needed as opposed to little gravity tug methods. The first thing that needs sorting out, however, are the words: meteor, meteorite, meteoroid and asteroid. Meteoroids and asteroids are objects in space. Meteoroids can be bits of asteroids or bits of comets. When they are burning through Earth’s atmosphere they are, for a few seconds, called meteors. If anything survives that fiery descent, the rocks found on the ground are called meteorites. 2012DA14 was not going “too slow” for a related fragment to arrive at 17km/second: its radiant, relative velocity to the Earth before being accelerated was 5.6 km/sec. If you add to that the free-fall velocity of 11.2 km/sec (the corollary of escape velocity) you get 16.8 km/sec. Add to that the eastward rotation of the earth at 55degrees north at an Azimuth of 9 degrees south of east (0.2 km/sec) you arrive at precisely 17km/sec. This is the same calculation that Zuluaga and Ferrin (and now, NASA) must have done in reverse for their version of the reconstruction of the trajectory: I calculated the radial speed of their hypothesised orbits at the Earth’s position (r value/ radius from sun=1AU) on the day of impact (but without the Earth’s gravitational influence added) and ended up with 34.8 and 35.2 km/sec for the 2 posited orbits. That amounts to 5 and 5.4 km/sec relative to the Earth, respectively. Adding the free-fall velocity and the eastward rotation you get 16.4 and 16.8km/sec. The difference between these posited orbits and the posited 2012DA14 fragment is that they invoke the head-on trajectory solution with little or no curvature as they are pulled into the gravity well. If it’s a bulls-eye hit the curvature is zero. The Zuluaga and Ferrin video shows the meteor coming in from about 3 degrees above the solar plane. The NASA video now shows the same.





Saying something is a coincidence is essentially saying that they do not understand how it is connected. To accept such an answer is a fool's folly. And as for retracing its orbit, that is based on an assumption that this meteorite's orbit was stable and just happened to connect with the Earth when it did. The reason they make these claims is that they are still working on 100 year old models of our solar system that ignore its electric/ magnetic nature.

In fact we barely survived the asteroid or comet strike at the end of the younger Dryas 11500 years ago. We all watched Shoemaker Levy 9 crash into Jupiter with huge force, if that had struck the earth instead it would have been the end of humanity and yet funding for this area of science if virtually non existent. Asteroid strikes have shaped the world we live in and will do so again.. The danger is very real and unfortunately it will probably take a strike on a city to wake us up to the dangers...Its also a rare chance for us to come together as a species rather than trying to kill each other.....On the 'imagine if' subject of a 9-km wide asteroid impacting on the ocean, one wonders what the height of the tsunami wave would actually have been....Given that the deepest ocean is 11 Km (Mt. Everest is 8.8 Km by comparison), I see no reason why a tsunami wave might not exceed the height of Everest. Now that would be a surfer's paradise....The asteroid would probably vaporize a volume of water that would be hundreds of times its own mass also. By my calculation, a volume of water the size of Mt. Everest hitting the coast of California would be 250 billion cubic meters of water, enough to cover 2500 billion square meters to a depth of 10cm, which would only reach about 1600 Km in land. So dinosaurs east of Colorado would not even have got their feet wet, and given the natural barrier of the Rocky Mountains, I'm probably being conservative.

NASA didn't even send a woman into space until 1983, twenty years after the Soviets sent Valentina Tereshkova! They had female astronauts in training for the Apollo missions but they never got to fly because the men said it wouldn't be fair for men to miss out. Seriously. Meeting the requirements for astronaut selection were also very difficult for women. Men could get the test pilot training and flight hours through the military. Women couldn't. There's a huge gap in space science. It's a very tough field to be a woman in. From the attitudes of some of the men, to the constant assumptions about a woman's inability to do a job, it can be a nightmare. If you make a tiny mistake, it's because you were having a bad day and doesn't affect your ability to do your job, it'll be forgotten in a few hours. If a woman makes a mistake, it's because she's female and proof that women can't do the job, and it will be brought up repeatedly. That's just one tiny example of the problems women face in the industry. How women cope in the "tech bro" culture of Silicon Valley, I don't know.

We will all need to rush to the closest college or university to find a safe space to read "The Calculating Stars" and also twitter about our feelings on reading it until the comet is adequately shamed.


PS. My favorite dinosaur is the ornithomimus. I always goes for the underdog, me. If you had the ornithomimus card during dinosaur Top Trumps you were going home early. I bet T Rexes were all like, 'You won't be getting in the films, mate,' back then, and the ornithomimus would try and make a w with it's fingers but the arms were too short, it was just to v's. Imagine if they'd tried to film Clueless back in them days; that would mess that scene right up. Just goes to show, technology and culture basically proceeds at the speed it should. Always wondered why dinosaurs never developed technological intelligence seeing as they were around for so long. Perhaps they did and set off for the stars leaving the unintelligent lot behind? Because they laid eggs? Crocs have been around a very, very long time too, but laying eggs limits how much offspring can develop. Or because their claws got in the way of typing? Nah, opposable thumbs; it all comes down to those.

PPS. https://cneos.jpl.nasa.gov/sentry. Those clever people over at NASA put this together ready for their briefing session with Bruce Willis.

2 comentários:

Book Stooge disse...

So you are a woman at work? Does your wife know about this behavior or was this post your subtle way of letting her know?

The Book of Revelations talks about the "star" Wormwood falling from the heavens and poisoning X percentage of the seas and destroying X percentage of this and that. The 3rd, of 7, Trumpets heralding the Last Days before Christ comes back. And then things get really bad.

Sounds like a strike to me...

Manuel Antão disse...

Nope. I'm a father with two daughters who wants both of them to have the same opportunities my baby boy will have in the work market.

The biggest flaw with this story is the unspoken assumption that deniers would actually care if large parts of the world's culture disappeared under the sea; such is my level of pessimism that I'm now convinced that it is only when Wall Street, and the City of Lisbon are submerged that some people will take notice.