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posted by janrinok on Monday June 11 2018, @04:47PM   Printer-friendly
from the anthropogenic-lost-records dept.

Science Alert has a story about a long running Lunar temperature measurement that apparently was lost and forgotten for decades.

Between 1971 and 1977, Apollo scientists conducting experiments on the Moon discovered that the surface of our li'l satellite buddy got mysteriously warmer. But the data from 1974 onwards went missing, and the strange warming phenomenon remained an enigma. The experiment was called the heat flow experiment, and it was designed to determine the rate at which the interior of the Moon loses heat.

Astronauts with Apollo 15 and 17 drilled holes into the lunar surface, up to depths of 2.3 metres, and probes measured the temperature at several depths in the holes.

These were long-term experiments, left in place after the astronauts departed, and transmitting data back to Earth.

The measurements revealed that the temperature of the moon at all measured depths got warmer from the date the experiment started in 1971 all the way till measurements ended in 1977.
That's a relatively short period of time on a planetary time frame. A rate of warming that rapid would have the moon surface incandescent well before we were began squabbling over who got to live in the best caves.

Various theories were put forth, but in the end people pretty much agreed it must be our fault.

In typical NASA fashion, the data was archived on tape, filed in the tape vault, and promptly forgotten, lost, moved, etc. Decades later, someone went looking for it. Some 440 tapes were found, (less than 10%) badly degraded over time. Some were recovered, Logs (written ones on that old unreliable medium: Paper) were found and when combined these sources recovered significant portions of the long lost data.

After 8 years of analysis, the data showed that the warming continued, all the way through until the end of observations in 1977. It also showed that, closer to the surface, the warming was more pronounced; and the warmth reached the shallower depths sooner, suggesting that the warming was occurring from the surface down, rather than radiating out from the Moon's interior.

So were the astronauts doing that? The researchers believe that their movements were disturbing the dirt on the lunar surface.

"Recently acquired images of the Lunar Reconnaissance Orbiter Camera over the two landing sites show that the regolith on the paths of the astronauts turned darker, lowering the albedo," they wrote in their paper.

"We suggest that, as a result of the astronauts' activities, solar heat intake by the regolith increased slightly on average, and that resulted in the observed warming."

In other words, when they stomped about and drove lunar rovers all over the landing sites, the Apollo astronauts overturned the topsoil, exposing darker regolith underneath. Darker surfaces don't reflect as much light; instead, they absorb it.

So this darker lunar surface at the Apollo sites absorbed more of the Sun's heat, raising the Moon's surface temperature by a few degrees.


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  • (Score: 0) by Anonymous Coward on Monday June 11 2018, @06:15PM (4 children)

    by Anonymous Coward on Monday June 11 2018, @06:15PM (#691520)

    we can demonstrate that more CO2 in air causes it to warm up in fairly simple lab experiments [acs.org].

    The link (https://www.acs.org/content/dam/AACT/middle-school/gases/.../lab-greenhousegas.pdf) doesn't work:

    We're Sorry :(

    We aren’t able to complete your request.

    Anyway we can guess what was there, I bet it measured the temperature of something in an enclosed insulated container. I would not extrapolate from that to a gravitating gas that can expand (eg troposphere height varies a lot between the poles and equator) and is in equilibrium with a high heat capacity liquid.

  • (Score: 2) by Thexalon on Monday June 11 2018, @08:36PM (3 children)

    by Thexalon (636) on Monday June 11 2018, @08:36PM (#691592)

    Sorry about that: correct link [acs.org]. This targets middle-schoolers.

    --
    The only thing that stops a bad guy with a compiler is a good guy with a compiler.
    • (Score: 0) by Anonymous Coward on Monday June 11 2018, @09:35PM (2 children)

      by Anonymous Coward on Monday June 11 2018, @09:35PM (#691626)

      Ok, the experiment is filling two 2 liters halfway with water stoppering the top and shining a heat lamp on them. Then you drop 3 alka-seltzer tablets into one, restopper it, and measure the temperature of the air in the upper half of both. Then at the end you use your chromebook to explain "How have humans contributed to an increase in carbon dioxide levels in the past 100 years?"

      So what are we looking at here? Overall: NaHCO3(aq) + H20 -> NaOH(aq) + H2C03 -> NaOH(aq) + H20 + CO2(g)

      The sodium bicarbonate is going to dissolve in the water and produce carbon dioxide gas which is net endothermic. This gas then effervesces into the air pocket in the upper half of the two liter and increases the pressure. So the water temperature will decrease due to a chemical reaction while the air temperature increases due to increased pressure. What does this have to do with the proposed "greenhouse effect"?

      • (Score: 0) by Anonymous Coward on Tuesday June 12 2018, @12:12AM (1 child)

        by Anonymous Coward on Tuesday June 12 2018, @12:12AM (#691675)

        What does this have to do with the proposed "greenhouse effect"?

        If you can't work out a solution by yourself, you have no standing in criticizing the experiment.
        (just in case you can't: just wait a bit before shining the light again for the temperature to become equal in the two recipients).

        • (Score: 0) by Anonymous Coward on Tuesday June 12 2018, @01:35AM

          by Anonymous Coward on Tuesday June 12 2018, @01:35AM (#691729)

          Where is "wait a bit before shining the light again" in the procedure? It just has them "turn on the light" (step 6) and then leave it on for 40 minutes.