I am away this week, visiting the Kennedy Space Center and hoping to see the launch of MAVEN. I was kindly invited, along with my family, by Elliot Goldman, an SGU listener who works for Lockheed Martin, the company who built the MAVEN craft. At the mission briefing yesterday they said there is a 60% chance of launch – scattered lightening storms are predicted which may interfere with the launch. The skies look pretty good this morning, so I am keeping positive.
MAVEN stands for Mars Atmosphere Volatiles EvolutioN. The probe will insert into Mars orbit (no lander) in a highly eccentric orbit in order to study the atmosphere of Mars. The craft will also do double duty as a communications relay to the current rovers on Mars, Opportunity and Curiosity.
The atmosphere on Mars is 0.6% that of Earth, barely a wisp. We know, however, that Mars once had a much thicker atmosphere. There are clear signs of rivers and bodies of water on the surface of Mars. This would require not only that the temperature was above freezing, but that there was enough atmospheric pressure to keep the water from just bubbling away.
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Just a quick post today as I am busy covering the inpatient service. The Lunar Reconnaissance Orbiter (LRO) has taken another stunning picture of an Apollo landing site, this one from Apollo 16. The photo shows a clear shadow from the American flag that was planting during that mission. The LRO has taken the highest resolution photos of the lunar surface from moon orbit, showing great detail of the Apollo missions. You can see the foot trails of the astronauts and all the equipment they left behind.
Because there is only extremely slow erosion of the moon’s surface, from micrometeorites, the lunar surface is essentially frozen in time, recording the activities of the astronauts who visited.
The flags have apparently lasted well. The only Apollo flag that is not visible is from Apollo 11, because that flag was knocked over by the exhaust when the lander blasted off the moon’s surface.
Of course I have to point out that these LRO photos are the nail in the coffin of absurd moon landing conspiracy theories (as if that were needed). For years conspiracy theorists asked why telescopes have not pictured the Apollo landing sites. That is a common strategy of conspiracy theorists – throw out questions about evidence that appears to be missing in order to make it seem curious or sinister, and without putting it into proper context or truly searching for an answer to their question. In this case telescopes are not suited to close up images of the moon. We needed to get a probe close to the moon’s surface. Now that we have, the asked for pictures are coming back.
Of course, no evidence will convince a die-hard conspiracy theorists. The evidence just becomes part of the conspiracy.
NASA has recently announced that their Cassini mission to Saturn has detected a thin layer of oxygen around the small moon Dione. The layer is so thin they are not calling it an atmosphere, but an exosphere. This is an interesting new piece to a picture that has been developing over the past few years – the chemistry of the Saturn system and how the moons influence the planet and each other.
One reason this is interesting is because oxygen is often thought of as a chemical signature for life. Free gaseous oxygen is highly chemically reactive, which means it won’t hang around for very long. It will react with other substances and be chemically bound. If there is gaseous oxygen in the atmosphere of a planet, therefore, there must be a source of new oxygen being made. On earth the source of oxygen is plant life – plankton and other plants make energy from the sun, take CO2 from the air as a source of carbon, combine it with water and release O2.
This further means that if we find oxygen in the atmosphere of a planet, either in our own solar system or an exoplanet in another solar system, this would be a clue that the planet might harbor life. The other possibility is that there is some chemical reaction going on that is producing the oxygen. That is likely the case with Dione.
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Perhaps you have heard that the world of astrology is “in a crisis.” Some are calling it the “Zodiac crisis” – because “Zodiac” is a cool-sounding word that starts with “z”. This is all really a manufactured non-event by Minnesota astronomer Parke Kunkle, who decided to send out a press release informing astrologers and the public that their signs are all wrong.
This is all, of course, old news. Sun-sign astrology is supposed to be based on the constellation that the sun is in at the time of birth. The Babylonians made the 12 signs 2000 years ago. They left out a 13th constellation, Ophiucus, because they wanted there to be only 12. But worse, astrologers at the time did not know about precession.
The earth rotates like a spinning top – the earth spins and has an axis tilted to its rotation about the sun and for the same reason a top will rotate its axis, so does the earth. The earth goes through one precession cycle every 26,000 years. That means in the 2,000 years since the Babylonians locked in their dates for the astrological signs, the dates that the sun is actually in those signs have shifted by 1/13 – or one sign.
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Here we go again – in an article that would make Deepak Chopra proud, Robert Lanza over at the HuffPo has written a mystery-mongering piece about biocentrism. Lanza asks the question – Why are you here? This is one of those cosmological questions that borders on metaphysics, like why is there something rather than nothing? These are interesting questions, but one needs to tread carefully along a tightrope of logic amid a chasm of philosophy and ideology. Lanza dives right off the cliff into the chasm. He sets up the question:
Even setting aside the issue of being here and now, the probability of random physical laws and events leading to this point is less than 1 out of 100,000,000,000,000,000, 000,000,000,000,000,000,000,000,000,000,000, equivalent to winning every lottery there ever was.
The lottery reference is appropriate, because Lanza is committing the lottery fallacy. In fact, his entire article is one giant lottery fallacy. This fallacy comes from reasoning backwards about probability and asking the wrong question. If John Smith wins the superball lottery with odds of 100 million to one against, this should not be considered a cosmically unlikely event that requires a special explanation. The wrong question to ask is – what were the odds of John Smith winning? The correct question is – what were the odds of anyone winning (pretty good, it turns out).
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Dark matter is cool – not necessarily its actual temperature, but as a scientific concept. It is one of the scientific mysteries of our generation, and it’s a fascinating story that is unfolding before our eyes with each new discovery. It’s just a good science story. A recent observation has just added to the drama, perhaps calling into question dark matter’s existence.
Dark matter is a helpful example of how the scientific process sometimes works. Scientists first proposed the notion of dark matter to explain anomalies in the rotation of galaxies – they rotate faster than they should, indicating that they have more mass than is visible. It’s as if they have lots of matter that is not visible – dark matter.
Dark matter became a working hypothesis to explain our observations about the universe, especially how galaxies move. But all scientific theories, in order to be of any value, must not only have explanatory power, they also need predictive power – they must make predictions that allow the theory to be tested.
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There has been much talk in recent years about the ongoing discovery of exoplanets – planets around suns other than our own. The technology to detect these distant objects has been increasing recently. There are two primary methods for detecting exoplanets: One method is to look for the wobble in the parent star caused by the gravity of the planet. The planet and its star revolve around their center of gravity, which will not be in the dead center of the star itself, but off center, causing a wobble.
The second method is called the transit method in which we look for alterations in the amount of light we can see from a star because of a planet that moves in front of it. This requires that the view of this system from the earth is roughly in the plane the planet is orbiting – the planet has to move in front of (transit) the star from our perspective. The new Kepler telescope is designed to detect light from many stars with sufficient sensitivity that it can find small (earth-size) planetary transits.
With all the talk about exoplanets, there has been, until now, little talk of exomoons – moons around planets around other stars. Until Kepler it has simply not been possible to detect exomoons. David Kipping of University College London has now published a paper in which he says that this is feasible.
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