C/2084 N1

21 07 2011

Eleven months after Planetfall, a bright, magnificent comet appeared between Scorpius and Ophiuchus.

Its discoverer named it not after herself but for the middle name of a grandmother left long behind on Earth. Ironically, Comet Tsumugi was discovered as a dirty smudge through a telescope only days before its nucleus began a period of intense outgassing and was visible to all, even during daylight.

It had three visible tails that stretched across forty degrees of the sky, and as it made its closest approach to Fram, it brightened up to magnitude negative eight. The two bluish tails were of ionized gases, and pointed in two directions away from Alpha A and Alpha B. There was a broader, curved tail of dust, and in this dust tail, spiral structures appeared. Tsumugi was laid like a striated carpet across the southern hemisphere of Fram’s sky.

The astronomers explained that it was a fresh comet, as unseen by Fram as it was by those who had so recently come to live upon her surface. Its first journey into the inner system from the Oort Cloud brought it whipping around Alpha B in an elliptical orbit that was deeply declined to the plane of the ecliptic. Its perihelion was a bare thirty-five million kilometres from the star; its closest approach to Fram was a hundred and twenty million kilometres.

Tsumugi’s surface was a dark, primordial crust of frozen carbon dioxide, methane, ammonia and heavy long-chain organics that protected its core of water ice. The light of two main sequence stars warmed the crust, and it absorbed this warmth, its darkness reflecting barely four percent of the light it received. Outgassing began when exposed water ice began to sublimate.

After it passed perihelion, Comet Tsumugi was visible even during those hours of daylight when both suns were in the sky. It was a commanding, inspiring sight, a vision of the beauty of the Universe, made all the more special by the bitterly cold and immense gulf between Fram and Home.

The astronomers also explained that, back Home, great comets were visible from Earth on average once a decade. They said that great comets would be much more frequent in the Alpha Centauri system – with its dense scattered disc and dispersed Oort Cloud, filled with the material that had composed the gas giants around Sol, and disturbed by the interactions of three stars. We would see many more great comets.

But never again Tsumugi. Gravitational perturbations caused by the two stars sent Comet Tsumugi slinging out into an orbital period of millions of years. The comet looped around Alpha B and sailed gracefully back out to the deep scattered disc, to be lost forever in the night…

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Closed Session

30 05 2011

ClosedSession

Lit by the white light of the projector, the faces of the Presidium remained blank. Faraday, sitting next to Stepan, crossed his arms.

“Okay,” Stepan managed awkwardly, and brought up the next slide. “From the top. This is the data that the GBM squeezed from the burst we detected three weeks ago. As you can see, it’s a short-duration spike that tails away quickly. The spike peaked at precisely 17.59 mega-electron volts. We turned the satellite on the source after the burst was detected, but were unable to detect an afterglow.”

Gina Divero, representing Alpha-2, spoke up. “And that’s unusual?”

“Oh yes. The energies involved in the events which generate gamma ray bursts are…well, almost beyond description. So powerful that we’ve detected the afterglow of GRBs across thirteen billion light years.” Stepan skipped ahead a few slides to a series of pixelated images of orange and red spheres. “We’ve never detected one in the Milky Way because, not only are they exceedingly rare, but a GRB in the Milky Way would be nothing short of an extinction event.”

“But its says here,” Charles Clarendon, representing Alpha-3, read from his tablet, “that you established the point of origin?”

“We think so.” Stepan fumbled with the slides. “Without an afterglow, we could not measure the redshift of the light, and so could only determine a direction – not a distance. But along that path we quickly find – ”

A touch of Stepan’s fingertips to the tablet, and an animation was projected onto the wall that showed Alpha A and B orbiting their mutual barycentre. There was Fram, just for a moment, a delicate bead suspended on a line tracing its orbit; but then the image quickly panned out, and a line travelled away from the twin stars, passed Sol, bounced from a red marble labelled Lalande 21185, and intersected with another binary system far to its left. The image zoomed in on a small, red dwarf and its even dimmer companion.

“FL Virginis.” Stepan froze the image on the mysterious binary. “Or Wolf 424, if you prefer. A binary system of an M5-class red dwarf and an unknown companion, probably a high-mass brown dwarf. An utterly unremarkable system, cold and dim, deficient in metals and with little hydrogen. Barely more than a dozen light years away, so the source was clearly not a gamma-ray burst.”

Figures suspended on the lines between stars suggested that Lalande 21185 was equidistant from both Alpha Centauri and FL Virginis – 8.2 light years in each direction.

“But the source, this star, is a flare star, I read from your report,” Clarendon inquired.

“Yes.”

“Yes,” Clarendon repeated, but in an expectant tone.

Gina asked, “Could this be the cause of the spike you detected?”

“That’s what I thought, at first,” Stepan responded, “but my colleague Elzette Skovgaard has spent much time refuting the theory. Flare stars unpredictably and dramatically increase in brightness along visual spectra. They’re usually red dwarfs, like FL Virginis A – ”

“And Proxima, yes?”

“ – and like Proxima. And they’re usually binary or trinary systems, where another member of the system might induce contortions in the star’s magnetic field. Like a solar flare. Using Proxima for data, she’s shown that flare stars can radiate in the visual spectrum, X rays and radio waves – but don’t tend to flare gamma rays. But I don’t want to step on Konrad’s toes here.”

Stepan slid his tablet to Faraday, who cleared his throat.

“Yes. And of note here is the precise energy detected by the satellite.” Faraday changed slides, and the figure 17.59 MeV appeared on the wall. “This is the precise amount of energy – the precise amount – shared by the high-energy neutron and an alpha particle formed in a thermonuclear reaction between a tritium and deuterium nucleus.”

“Tritium,” Clarendon repeated. “Deuterium.”

“Indeed,” Faraday continued, “and tritium occurs irregularly in nature. Occasionally in atmospheres containing hydrogen and nitrogen that interact with cosmic rays.”

Stepan spoke up. “And, as I noted before, the Virginis system is deficient in hydrogen.”

“And these other possibilities you mentioned here,” Gina asked, skimming the report quickly, “you discount each?”

“I thought, maybe, that we’d detected a magnetar or a pulsar, directly behind FL Virginis, visible through gravitational lensing. But look at that spike. It’s a one-off; it hasn’t repeated in the three weeks since its first detection. For the same reason, it’s not a soft gamma repeater. We’d see oscillations related to its rotation period.  So then I thought that the red dwarf had developed an accretion disk, and that its companion was ploughing through that disk and generating pulses of gamma rays with each interaction. But we know the brown dwarf’s orbital period, just over sixteen years, and we’ve never detected a burst like this before –”

“We keep coming back to two things,” Faraday said impatiently. “First, FL Virginis is an unexceptional system. Second, the energy detected was precisely that of the fusion of deuterium and tritium.”

“And hence,” said Clarendon, in a low and foreboding voice, turning to the gathered members, “the closed session of the Presidium. You’re saying that, in a star system essentially two doors down, you’ve detected evidence of the detonation of a hydrogen bomb…”





The Mysterious and Wonderful Universe

1 06 2010

Mysterious Universe

“I’ve never seen anything like it.”

Elzette leaned over Stepan’s shoulder and stared at the line graph on the screen of his terminal. The line crept along the X axis before jumping sharply up along the Y axis, peaking at a short plateau, and then almost as quickly dropped away. The line flickered every few seconds, and its shape changed almost imperceptibly. Data was still coming down from the satellite and being uploaded through the network; Stepan’s terminal continuously updated the fields displayed by the graph.

“It’s a light curve, Stepan. You see a dozen a week.”

“But not like this,” he insisted. He ran his stylus along the crest of the line graph. “Look at this plateau. Have you ever seen a GRB that didn’t spike?”

Elzette rolled her eyes and returned to her own terminal. “You know better than anyone that light curves from gamma-ray bursts are never the same. What was the duration of the emission?”

Stepan ran his stylus along the bottom of the graph, reading the measurements on the X axis.

“Only a few microseconds.”

“Now I don’t know much about GRBs,” Elzette sardonically replied, “but that would fit just right for a short gamma-ray burst, yes? Less than two seconds?”

“Maybe. Short GRBs are usually around point three of a second in duration. But, look at the energy levels…”

Elzette smiled to herself and shook her head. She focussed on the spectroscopic data on her own screen and let Stepan talk aloud.

“…less than 20 million electron volts! I’m surprised GLAT even detected it. GRBs are of much higher energies, in the order of tens of billions of electron volts. How else could we detect such things across the observable universe?”

Stepan muttered to himself in MeV and GeV and orders of magnitude of hertz.

“And this wavelength,” he said louder. “On the far end of the gamma-ray scale, close to ten picometers. Seriously, Zet, this is strange. We need to turn the satellite on the afterglow.”

Elzette sighed, and spun in her chair to face Stepan.

“You know better than I that it’s spectacularly difficult to spot the afterglow of a short GRB – ”

“ – I don’t think it’s a GRB, Zet.”

“Solar flare? There are three stars nearby, two of which are thermonuclear furnaces pouring out gamma rays.”

Stepan shook his head. “Alpha B has set, and there’s been no surface activity on Alpha A.”

“Well, what else? A neutron star? Blazar? Seyfert galaxy? It might well be the cosmic microwave background.”

“No. No, the wavelength and duration and energy levels are all wrong.” He checked the data still coming down through the network. “17.59MeV. About the same amount of energy released when tritium and deuterium nuclei fuse to form alpha particles and high-energy neutrons.”

Stepan’s terminal announced that it had completed downloading the information from the satellite. The line graph froze in place, and more information scrolled through the margins of the graph. Stepan trawled through this data.

“What is it?” Elzette asked.

“The GLAT didn’t detect this incident,” Stepan explained. “Like I thought, the pulse wasn’t powerful enough. The Large Area Telescope is designed for bursts in the range of 30 MeV to 300 GeV. The Gamma-ray Burst Monitor package picked it up. GBM has banks of silicone detectors, organised in successive layers; from the data each of these detectors gives us, we can work out where the burst came from…wow.”

Elzette stood and again leaned over Stepan’s shoulder. On the graph, lost among the other marginalia, the computer calculated the origin:

288.7827 +71.3917

“That’s FL Virginis B. That’s practically next-door.”

Elzette held Stepan’s eyes for a moment, and then threw her hands up in defeat.

“Alright! Fine. Realign the satellite for the afterglow. That’s what GLAT is there for, right?”





Across the Sea of Stars

21 08 2009

CA-772 Grape OS

"The CA-772 Grape orbital utility pods were plentiful around the space facilities above Fram, proving to be of great use during the Texas crisis.  Pilots found their versatility in their relative simplicity; a primary computer-simulation projected itself upon the inside of the iconic domed cockpit, giving a stark vector-driven interpretation of the outside vacuum and objects.  Pilots appreciated this Spartan representation, with the ability to toggle target rendering of objects via distance in varying levels of overlay.  The Grape itself was powered via solar panels, which fed into the small ion propulsion engine and life support systems.  While not the most comfortable of vehicles, they offered a level of reliability and ruggedness unparalleled over Fram."

It had been almost a month since Mayflower had arrived.

It was a slow process to bring the material down from Wilbur to Charlotte. The ribbon that connected the two was much shorter than those which had been built on Earth; Fram was a smaller world, with less gravity and thus a lesser exit velocity, and possessed a longer rotational period. This meant that it took less than a day for a climber to run the length of the ribbon, compared to the week it took to run the length of the Earth elevators.

We wanted to bring down as much material as we could with our limited number of climbers. This meant that we had to intersperse the payload-laden climbers so as not to stress the cable: the closer our laden climbers were to the Wilbur counterweight, the greater the lean in the cable as coriolis force produced by Fram’s rotation acted upon the mass of the climber. We joked that one day we would not have to worry ourselves with this effect – as with each of our shuttle launches, the ascent of a climber robbed Fram of a fraction of its rotational momentum. At some indeterminate point billions of years in Fram’s future, assuming the space elevator continued to run, Fram’s orbit would slow to a halt.

We were powering the climbers by using the solar farm on the surface, which was not the most efficient method and reduced our capabilities further. Eventually we hoped to power the cable itself, using the conductivity of the carbon nanotube. Plans were drawn up in which the Quoqasi’s fusion plant, now useless, would be moved down to the surface and installed at Charlotte Station.

And so we unpacked Mayflower, day by day shuffling more material down to the surface.

Already Charlotte had grown into a bustling hive of activity, spread over hectares of carbon sheeting. KOVTARs worked at unloading the climbers during the night. In the marshalling yards were pallets filled with new equipment: fixed-wing cargo planes and their associated launch loops, a new generation of integrated tracked-biped walkers, over the horizon radars, hydroponic domes, mining lasers, and more. Most important were the tanks of consumables, twice as tall as a KOVTAR. These were painted according to their contents: blue for oxygen, green for nitrogen, red for deuterium, purple for iodine. Their edges were stencilled with checkers and their faces with the chemical symbol of their contents. These would open up of closed-loop life support systems and give us a redundancy we hadn’t enjoyed since leaving Jupiter, or power the fusion plants for years to come.

While the crew of Port Mayflower worked to unload our supply ship and send this material down to the surface, the Grapes went to work disconnecting components of the Mayflower’s payload. A pair of probes were nestled in the lee of the May’s cargo modules, fore of the drive stack. It had taken a fortnight to safely cut through the remains of its protective sheath of ice and disconnect them from the Mayflower, and another fortnight to perform diagnostic checks of their hardware.

These probes were themselves larger than an orbiter, each the size of a naval cruiser. They were of a similar dark grey to the hull of the orbiters and the Grapes, although sections of the engine were the lighter white-gray of beryllium. The nose of each probe was a cluster of instruments, spectroscopes, enormous optical and radio telescopes, and repeller fields like those which shielded the Quoqasi and Mayflower from the interstellar medium. Buried in the hull behind these were the probes’ central computers, replete with communications systems. Just behind the bulbous nose was a ring of a dozen small spheres, situated at points of the hour on a clock around the probe’s nose. These were sub-probes which would launch from the mother probe once targets had been identified.

The defining feature of each of these probes was the payload stage. Around the midsection of each probe were six spheres, each a hundred and fifty meters in diameter, clustered around the fusion engine like berries on a stalk. Here was the reaction mass which powered the fusion rocket that spurted from the aft of each probe. Three tanks carried deuterium while another three carried helium-3, mined from Europa and Luna respectively.

These probes were designed to travel on from Alpha Centauri, to two more points of light in our sky.

Their targets had been selected long ago, after the decision had been made to colonise Alpha Centauri. Their targets were closer to Fram than they were to Earth, but only just so; sending them to us with the Mayflower hadn’t saved them a great distance. Rather, carried by the Mayflower, they saved reaction mass that could otherwise be spent travelling to their targets faster.

Their targets were a pair of M1 class red dwarfs about three to four times as far from Alpha Centauri as Alpha Centauri was from Earth. We had a number of designations for these stars, depending on whether one ascribed to the Gliese catalogue of nearby stars, or the Bonner Durchmusterung catalogue, or the Draper, or the Hipparchos… Despite these various catalogue designations, we had no names for these stars.

One probe was to be sent to BD +15° 2620, otherwise known as Gl 526; the other to Gl 832, itself also known as HD 204961. These stars were respectively just under seventeen and a half light years and fourteen light years from Fram.

RigelKent03

The probes would cover the distance at much greater speed than had the Quoqasi. Unencumbered by fragile humans and with a bounty of reaction mass upon which to draw, their fusion rockets would propel them at twenty-five gees of acceleration for four weeks. This would take each probe up to .90c – nine tenths the speed of light – a speed at which each would cruise before decelerating by a similar force and for a similar period at the conclusion of its interstellar flight.

At .90c, the probe to BD +15° 2620 would take nineteen years and two months to reach its destination; the probe to Gl 832 would take fifteen years and six months.

These stars were the next closest to Alpha Centauri on the road to a cluster of stars, coreward and trailing of Sol, which showed a good prospect for habitable planets. Surveys conducted from Sol using gravitational microlensing, observations of planetary transits of each star and variations in that star’s spectral lines had detected numerous orbiting gas giants. We knew, for instance, that Gl 832 had a gas giant named Bailey orbiting it at a distance of 3.4 AUs (we had named the planet but not yet its parent star). But our detection methods were limited by distance; the best way to determine if there were habitable, terrestrial planets around BD +15° 2620 and Gl 832  would be to get closer, or better yet, to visit the systems themselves.

The instruments buried in the nose of each probe would make observations of each system throughout its unpowered glide. These observations would be limited once each probe flipped end over end and decelerated; once this manoeuvre was complete, the probe would insert itself in an orbit that would bring it looping into the inner system. At this point the sub-probes would detach, and fire off to orbit and explore points of interest. They would send telemetry back to the mother probe, which would in turn tightbeam its findings back to Fram and to Earth. The most comprehensive of these findings, made while the probes orbited the target stars, wouldn’t reach us for thirty to forty years.

And so, as we continued to unload the materials sent to our colony by Earth, we prepared to send automated probes further on, across the sea of stars.

The Grapes transferred the probes to the orbiters, and the orbiters moved the probes half an AU from Fram before we sent the go order for the onboard computers to light the fusion torches. The workers unloading the latest material sent down from Port Mayflower noticed a new spark in the sky – at length this spark separated into two smaller points, one rushing toward a point eleven degrees down, the other seventeen degrees up, from the plane of the ecliptic…

 

 

A note on the use of the map in this post: this map was created by Winchell Chung of Project Rho, who kindly gave permission for its use to the authors of Orbital Shipyards. Copies of this map are available from Mr. Chung’s Project Rho Productions, and we highly recommend the quality of his work and direct our readers to his website and his store.