A Bit More Detail

Assorted Personal Notations, Essays, and Other Jottings

Posts Tagged ‘space travel

[BLOG] Some Friday links

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  • blogTO notes an upcoming group photo of prominent Toronto musicians.
  • Centauri Dreams speculates about the sort of starship a Kardashev II civilization would build.
  • The Dragon’s Gaze has a couple of papers noting the interactions between hot Jupiters and their parent suns.
  • The Dragon’s Tales reports on Russian nuclear submarine advances.
  • Joe. My. God. notes that same-sex marriage in Slovenia is safe and observes the advance of civil unions in Italy.
  • Lawyers, Guns and Money notes how revitalizing neighbourhoods can lead to complicated politics, politely put.
  • Marginal Revolution considers ways to improve the allocation of water in drought-hit areas like California.
  • The Numerati’s Stephen Baker wonders if Apple might be able to regain its lost customers.
  • Torontoist approves of a Haitian restaurant in a Scarborough strip mall.
  • Window on Eurasia notes the complexities of language policy in the former Soviet Union, looks at the institutionalization of Islam in the Crimea, and examines the issues of self-identifying Ukrainians in the Russian Far East.

[BLOG] Some Thursday links

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  • Centauri Dreams examines different ways in which starships can decelerate.
  • The Dragon’s Gaze links to a paper examining the potential habitability of exomoons orbiting bright white main-sequence stars, between F5 and F9.5. Ultraviolet radiation is key.
  • The Dragon’s Tales notes a Chinese ASAT weapons test.
  • Joe. My. God. notes the Swedish language now has officially added the gender-neutral pronoun hen to its vocabulary.
  • Language Hat notes an ambitious new project to digitize ancient Irish-language documents.
  • The Power and the Money’s Noel Maurer is critical of the Democratic Party’s stance on abortion when it gets in the way of necessary policy, likening it to the Republican Party’s ongoing satisfaction of its base.
  • The Planetary Society Blog notes the final interesting weeks of Messenger‘s survey of Mercury, with photos.
  • Peter Rukavina remembers when in 1995 he was commissioned by the government of Prince Edward Island to set up a provincial website.
  • Torontoist reacts with humour to the impending merger of Postmedia and Sun Media.
  • Towleroad notes a lawsuit brought by a Michigan women against her former gym for being too trans-friendly.
  • Understanding Society examines the mechanisms connecting experiments with policies.
  • The Volokh Conspiracy argues against mandatory voting and mandatory jury service.
  • Window on Eurasia observes a controversial election among Moldova’s Gagauz and looks at the extent to which Islam in Russia is not under the government’s control.
  • Yorkshire Ranter Alex Harrowell goes on at length about the ridiculous Biryani project, a failed dirty tricks effort to sabotage the English Defense League and radical Muslims. Wow.

[BLOG] Some Wednesday links

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  • blogTO notes that craft brewers would like to open their own retail stores in Toronto.
  • Centauri Dreams and The Dragon’s Tales both note that we now have the ability to detect starships travelling at very high fractions of the speed of light.
  • The Dragon’s Gaze links to a paper further refining the HR 8799 system.
  • The Dragon’s Tales notes Egypt’s plan to build a new capital city.
  • The Frailest Thing comments on the philosophical problems associated with the goal of extending life expectancy.
  • Joe. My. God. and Towleroad both note the failure of a Russian bid to prevent the United Nations’ offering of benefits to its married gay staffers.
  • Language Hat notes a Sanskrit humour column.
  • Marginal Revolution links to a study examining the changing nature of the language of World Bank reports.
  • Peter Rukavina notes that on some days, wind power is enough to supply all of Prince Edward Island’s electricity needs.
  • Spacing Toronto continues an ongoing examination of visual pollution.
  • Window on Eurasia notes a Russian interest, pre-Crimea, in emigration.

[BRIEF NOTE] On the false dream of Project Orion

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At The Space Review, in the article “Starfleet was closer than you think” authored by Major Brent Ziarnick and Lt. Col. Peter Garretson, the argument is made that the Project Orion nuclear bomb-powered spacecraft of the 1960s could and should have been made, that our world would now be an enthusiastically spacefaring world.

Today, the United States is in the process of a renaissance of interstellar thought and ambition. In the popular culture, with the discovery nearly every day of potentially Earth-like exoplanets, and popular movies like Interstellar, we are seeing an increasing public interest. And in the technical community, there is new leadership when it comes to actually designing interstellar capable spacecraft, such as DARPA’s 100 Year Starship project, Icarus Interstellar, and the Tennessee Valley Interstellar Workshop.

But we could have been so much farther along. After the publication of George Dyson’s book Project Orion, and a few specials, a lot of people know that in the early 1960s DARPA investigated the possibility of a nuclear-pulse-detonation (that is, powered by the explosion of nuclear bombs) spacecraft.

Most assume the program was cancelled for technical problems, but that is not the case. Few know how seriously the idea was taken by the top leadership of the US Air Force.

Preceding but also concurrently developed with Apollo, this extremely ambitious project had unbelievable payload capability. Where Apollo at 3,500 tons could only put two tons on the Moon, the smaller Orion (about the same total mass, 4,000 tons) could soft-land 1,200 tons (600 times as much) on the Moon, and the larger (only three times as heavy as Apollo, or 10,000 tons) could soft-land 5,700 tons (nearly 3,000 times as much) on the Moon, or take 1,300 tons of astronauts and consumables on a three-year round-trip to Saturn and back!1 The fission powered Orion could even achieve three to five percent the speed of light, though a more advanced design using fusion might achieve eight to ten percent the speed of light.

Most assume the program was cancelled for technical problems, but that is not the case. Few know how seriously the idea was taken by the top leadership of the US Air Force.

Because internal budget discussions and internal memoranda are not generally released and some only recently declassified, almost nobody knows how close Strategic Air Command (SAC) was to building the beginning of an interstellar-capable fleet. Had the personalities of the Air Force’s civilian leadership been different in 1962, humanity might have settled a good part of the inner solar system and might be launching probes to other stars today. We might also have had the tools to deflect large asteroids and comets.

This article was dissected by commenters over at James Nicoll’s Livejournal. Leaving aside the non-trivial technical challenges discussed over there, I would add that not only would fleets of spacecraft propelled by nuclear weapons make Earth orbit unusable for commercial purposes, but simply being able to get to Mars quickly is not enough. Do the life support technologies needed to sustain crews for hundreds of days exist? Is there anything on Mars, or elsewhere, that would actually attract sustained interest even with relatively swift interplanetary travel? I’m skeptical.

Written by Randy McDonald

March 20, 2015 at 10:05 pm

[NEWS] Three links on the import of the global ocean of Ganymede

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Back on Friday, news that evidence had been found of a subsurface ocean on Ganymede, Jupiter’s largest satellite, was widely propagating. Centauri Dreams’ Paul Gilster (““Evidence Mounts for Ganymede’s Ocean”) was one of the first bloggers on my RSS feed to report this.

Yesterday’s discussion of hydrothermal activity inside Saturn’s moon Enceladus reminds us how much we can learn about what is inside an object by studying what is outside it. In Enceladus’ case, Cassini’s detection of tiny rock particles rich in silicon as the spacecraft arrived in the Saturnian system led to an investigation of how these grains were being produced inside Enceladus through interactions between water and minerals. If correctly interpreted, these data point to the first active hydrothermal system ever found beyond Earth.

Now Ganymede swings into the spotlight, with work that is just as interesting. Joachim Saur and colleagues at the University of Cologne drew their data not from a spacecraft on the scene but from the Hubble Space Telescope, using Ganymede’s own auroral activity as the investigative tool. Their work gives much greater credence to something that has been suspected since the 1970s: An ocean deep within the frozen crust of the moon.

The early work on a Ganymede ocean grew out of computer models of the interior, but the Galileo spacecraft was able to measure the moon’s magnetic field in 2002, offering enough evidence for an ocean to keep the idea in play. The problem was that the Galileo measurements were too brief to produce an overview of the field’s long-term cyclical activity.

It was Saur’s idea to look at the idea afresh. Given that Ganymede is deeply embedded in Jupiter’s magnetic field, the aurorae that are produced in its polar regions are going to be influenced by any changes to that field, changes that produce a ‘rocking’ movement in the aurorae. These movements, Saur reasoned, would be a useful marker, one that, like the silica grains near Enceladus, could tell a story about activity deep below the surface. Says Saur:

“I was always brainstorming how we could use a telescope in other ways. Is there a way you could use a telescope to look inside a planetary body? Then I thought, the aurorae! Because aurorae are controlled by the magnetic field, if you observe the aurorae in an appropriate way, you learn something about the magnetic field. If you know the magnetic field, then you know something about the moon’s interior.”

The ‘rocking’ of the aurorae on Ganymede depends upon what’s inside the moon, and by the researchers’ calculations, a saltwater ocean would create a secondary magnetic field that would act against Jupiter’s field, tamping down the motion of the aurorae. The Hubble data show us that this is happening, for Saur’s models indicate the auroral activity is reduced to 2 degrees as opposed to the 6 we would expect if an ocean were not present. Ganymede thus joins Europa and Enceladus as an outer planet moon with increasing evidence for an ocean.

In “An internal ocean on Ganymede: Hooray for consistency with previous results!“, the Planetary Society Blog’s Emily Lakdawalla noted that this discovery fits with our understanding of Ganymede’s inner workings.

The Hubble results don’t precisely pin down the size and depth of an ocean at Ganymede, but the range of possible ocean thicknesses and depths is small. The observed behavior of the aurorae at Ganymede are consistent with a liquid ocean that is a relatively small fraction of Ganymede’s radius. Of course, Ganymede is a very big world, so “relatively small” in this case can mean an ocean up to about 100 kilometers deep. According to the paper, some possible oceans that are consistent with the results include, but are not limited to:
•A liquid layer from 150 to 250 kilometers depth with relatively low salinity
•A liquid layer from 190 to 210 kilometers depth with relatively high salinity
•A liquid layer below 330 kilometers depth with relatively high salinity

Water in one form or another at Ganymede goes from the surface to a depth of about 720 kilometers, at which point you reach Ganymede’s rocky outer core. So I think we can generalize these all to say: there is an ocean of less than 100 kilometers thickness located within a few hundred kilometers of the surface of Ganymede. In all possible cases, the liquid layer would be perched within the solid icy mantle, with solid ice above it of the form we have on Earth, and ice below it in a high-pressure crystalline form. [. . .]

That is a lot of liquid water, but it’s in a very different place within Ganymede than the liquid water that we think exists at Europa and Enceladus. Europa has a much higher proportion of rock to ice than Ganymede does, and is also warmer because of greater tidal friction; the same physics that predicted Ganymede’s perched-ocean-within-an-icy-mantle predicts that Europa’s liquid water ocean is in direct contact with its warm rocky core. Warm liquid water percolating among warm rocks is, by definition, hydrothermal activity. Hydrothermal zones are places that exobiologists imagine life might happen, because you have lots of energy and you have rich chemistry created in all that warm liquid water eating away at rocks. Earlier this week, one of the Cassini instrument teams announced that they had detected rock particles from just such an environment that originated within Enceladus.

At Discover‘s Out There blog, Corey S. Powell noted in “Looking for Life in All the Wrong Places?” that the existence of liquid water oceans has implications for the search for extraterrestrial life generally, and for the dispatch of space probes more specifically.

The story used to be all about Mars. Now it is clear that most of the water, most of the organic chemistry, and by extension most of the potentially habitable territory in the solar system resides on or in ice moons. If that’s true in our solar system, there’s a good chance it’s true around other stars across our galaxy and beyond.

Currently there are five orbiters and two surface robots exploring Mars. Here are the equivalent numbers for the four moons: Europa, 0. Ganymede, 0. Enceladus, 0. Titan, 0. It seems like we may have been looking for life in all the wrong places.

That’s the bad news. Now that good part. The Cassini spacecraft orbiting Saturn is performing local observations and occasional flybys of Enceladus and Titan. Archived information from NASA’s Galileo probe, along with new data from the Hubble Space Telescope, are deepening our understanding of Enceladus and Ganymede. Europe is working on a spacecraft called JUICE, which will examine Ganymede in detail. And the Obama administration is poised to approve the Europa Clipper, the first mission dedicated entirely to one of these icy moons; it could launch as early as 2022. In short, our explorations are starting to catch up with our fast-changing knowledge.

Getting to the next stage of understanding won’t be easy. The icy moons are far away, making them time-consuming and costly to reach. A trip to Mars takes about 8 months. Galileo needed 6 years to reach Jupiter, and Cassini’s voyage to Saturn was a 7-year undertaking. NASA also has a whole planetary-science bureaucracy built around the exploration of Mars. There are a lot of careers tied to the Red Planet.

At the same time, it’s hard to ignore the contrast. This past week, a group of researchers reported that the Red Planet probably had a vast ocean covering its northern hemisphere. It was an encouraging discovery, one that got quite a bit of news coverage. That ocean on Mars dried up about 4 billion years ago, however. The oceans of Enceladus and Europa are calling to us right now. If we want answers—if we want to find life, or the processes leading up to life—those are the places where we have to go.

Written by Randy McDonald

March 16, 2015 at 7:13 pm

[BLOG] Some Monday links

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  • blogTO takes a look at the reasons for the failure of the Toronto Sushi Festival, a failure that included the blog’s own misrepresentation of the event’s success.
  • The Broadside Blog’s Caitlin Kelly argues that, in our media-saturated environment, paying attention to everything is exhausting.
  • Centauri Dreams and D-Brief react to Dawn’s arrival at Ceres.
  • The Crux notes that Enceladus’ seas appear to be driven by tectonic activity, suggesting they may support life.
  • The Dragon’s Gaze looks at the remarkably eccentric orbit of exoplanet HD 8673Ab, links to a paper suggesting that hot Jupiters disrupt their planetary systems as they migrate inwards, and suggests that planetary systems discovered by Kepler with only one or two planets are the remnants of much denser systems.
  • The Dragon’s Tales and The Power and the Money discuss the idea of military unity in the European Union.
  • A Fistful of Euros compares the recent trajectories of Greece and Iceland following their
  • Joe. My. God. notes an Irish bishop who made an odd comparison of gay people to people with Down’s syndrome.
  • Language Hat notes that the Parisian journals of Russian exiles from the Soviet Union are online and notes the South Arabian language of the Yemeni island of Socotra.
  • Lawyers, Guns and Money considers if rudeness can be a firing offense.
  • Marginal Revolution criticizes the Greek government, and argues that Krugman’s criticism of the Trans-Pacific Partnership is misfounded.
  • The Planetary Society Blog calls for a return to Venus.
  • Otto Pohl observes that just over 62 years after his death, Stalin remains a popular figure in Russia.
  • The Power and the Money’s Noel Maurer notes worsening American-Venezuelan relations and argues that Venezuela’s PetroCaribe scheme hasn’t achieved its geopolitical goals.
  • Registan considers the controversy surrounding the disappearance of Vladimir Putin.
  • Peter Rukavina notes how, by tweaking an inexpensive Raspberry Pi computer, he can detect aircraft incoming to Charlottetown.
  • Spacing Toronto notes gendered violence on mass transit.
  • Towleroad observes the conviction of a California man on charges of intentionally trying to infect others with HIV.
  • The Volokh Conspiracy considers the legal issues surrounding an Indian state’s ban on beef, by comparison to California’s horse meat ban.
  • Window on Eurasia notes one Russian’s call to partition Ukraine, observes Russian irredentism towards the Baltics, considers the consequences of Russia’s statements about Crimea, looks at Hungarian irredentism towards western Ukraine, argues that a new Yalta is impossible, and compares the position of Vladimir Putin to that of Khrushchev afte the humiliating Cuban Missile Crisis.

[BLOG] Some Wednesday links

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  • blogTO and Torontoist both report on the remarkable Honest Ed’s plan. (More than a thousand residential units, all rental? That’s rare.)
  • The Dragon’s Gaze notes the confirmation of a hard-to-find hot Jupiter orbiting BD-20 1790.
  • The Dragon’s Tales reports on the mysterious explosion of an American military satellite.
  • The Everyday Sociology Blog observes that raw talent is not nearly enough to ensure, that capital of all kinds is needed.
  • Joe. My. God. celebrates Slovenia’s legalization of same-sex marriage and notes Russia’s effort to block benefits for the same-sex partners of United Nations employees.
  • Language Hat is apparently not fond of National Grammar Day.
  • Language Log is critical of the BBC claim that a southern African group cannot see blue.
  • Lawyers, Guns and Money starts a discussion about India’s new aircraft carrier.
  • Marginal Revolution suggests that the Greeks are badly overstretched as individuals.
  • The Planetary Society Blog’s Emily Lakdawalla considers Ceres.
  • Towleroad notes the Russian government’s revenge on an lesbian couple who embarrassed an anti-gay politician.
  • Transit Toronto notes that the TTC now has a fourth super-long streetcar.
  • The Understanding Society Blog looks at how knowledge is reproduced globally.
  • Window on Eurasia criticizes the geopolitics of Eurasianism and warns of Russian involvement in Latvia.
  • The Financial Times‘ World blog notes the many issues with the Greek job market.
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