Archive for the 'Astronomy' Category

Mar 27 2015

Dark Matter Collisions

Published by under Astronomy

The existence of dark matter is one of the coolest science stories of my lifetime. When I was growing up I was in love with pretty much every field of science, but particularly with astronomy, and at that time we had no idea that 85% of the matter in the universe even existed. We now know that the astronomy I was so fascinated with was actually the study of 15% of the matter in the universe. If you count dark energy, which makes up 68% of the universe, then dark matter makes up 27%, and everything that we thought was the entire universe is actually only 5% of the universe.

This story dramatically contradicts every crank and pseudoscientist who tries to tell you that scientists only support the status quo. In my lifetime we discovered 95% of the universe, without any prior theory telling us to expect this result. (Dark matter was hinted at in observations of galaxy rotation, but not generally accepted.) The discoveries were based on unexpected observations, that broke our models of how we thought the universe worked. Scientists met these new ideas with skepticism, but explored them further, and were slowly convinced by mounting evidence. Now dark matter and dark energy are generally accepted – because the evidence convinced the scientists. That is how science works, kids, so don’t believe the cranks.

Dark matter is a powerful idea, even though we currently don’t know what it is, because it not only explains observations that otherwise don’t make sense, it makes predictions. Predictions are the key to scientific progress. They provide the opportunity to test ideas against reality. If an idea does not make any testable predictions, right or wrong it’s just worthless. (Not even wrong.)

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Mar 20 2015

Titius-Bode Law and Exoplanets

Published by under Astronomy

A recent Washington Post headline reads: Most stars in the galaxy have planets in the habitable zone, according to new research. Some version of this headline was attached to every mainstream media reporting on this story. Not just the headlines were this hyped – most of the time the reporting presented this new research as if this is an accepted conclusion.

I have been following our exoplanet explorations since they began. Like many astronomy enthusiasts, I am particular interested in a few questions – how many planets do stars have on average, what are the typical arrangements of those planets, how typical or atypical is our own system, and how many earth-like planets are out there? We are starting to get a good idea of how many exoplanets are out there – most stars likely have multiple planets.

The other questions are still open at this time. While we are gathering more and more data points, with hundreds of systems now known to have planets, and currently 1,821 confirmed exoplanets. There are a couple thousand more possible exoplanets awaiting confirmation.

This may sound like a lot, but it really isn’t nearly enough data points to answer the remaining questions above. One problem is that we don’t have a thorough survey of each system. We are finding planets that are the easiest to find – those close to their parent stars, and larger planets. Small planets far from their stars would be almost impossible to find given current methods. They would not have a significant gravitational effect on their parent star, and even if they happened to transit their star they would probably have an undetectable effect on the light from that star. Also, with periods of hundreds of years, it would take hundreds of years to confirm them by the transit method.

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Feb 02 2015

Gravity Waves and Science Self-Correction

Published by under Astronomy

In 2011 scientists tentatively reported that they may have detected neutrinos traveling faster than the speed of light in apparent contradiction to the theory of relativity. By early 2012 the technical error that led to the apparent discovery was revealed.

Also in 2012 scientists reported that, using the Large Hadron Collider, they probably found the Higgs boson, the particle responsible for mass. However they were still not completely sure so they kept testing, and then last year they announced that indeed they did identify the Higgs as predicted by the standard model of particle physics.

In March of 2014, in what was definitely the biggest science news story of the year scientists reported detected gravity waves from the Big Bang, confirming the theory called the “inflationary universe.” The discovery was hailed as a “smoking gun.” Space.com at the time wrote:

If it holds up, the landmark discovery — which also confirms the existence of hypothesized ripples in space-time known as gravitational waves — would give researchers a much better understanding of the Big Bang and its immediate aftermath.

In those four little words, “if it holds up,” lies the essence of science. This is just a sample of recent big science news stories that reveal the process of science – skeptical questioning of all claims and testing those claims against objective evidence.

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Jan 16 2015

Trans-Neptunian Objects

Published by under Astronomy

My mental map of our solar system has evolved over the years, as I have learned more about astronomy and as astronomers have learned more about our solar system. When I was younger that mental map ended with Pluto, the ninth and outermost planet of our system. I then learned that Pluto’s orbit takes it within the orbit of Neptune, and from 1979 to 1999 Neptune was actually the furthest planet.

My mental map expanded greatly when I learned about the Kuiper belt and the Oort cloud (I can’t remember now which one I learned about first). The Kuiper belt is a doughnut shaped region of space beyond Neptune that contains many small icy worlds. The Oort cloud is a spherical shell farther out still that contains small chunks of dirty ice and is likely the source of many long period comets that sometimes fall into the inner solar system. Short period comets likely come from the Kuiper belt.

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Jul 22 2014

Aliens are Sinners

To paraphrase Carl Sagan: in one unremarkable galaxy among hundreds of billions, there is an unremarkable star among hundreds of billions of stars in that one galaxy. Around that star revolves a world with life. Some people who live on that world believe they are the center of the universe.

Sagan nicely puts into perspective how absurd it is to believe, given our current knowledge of the cosmos, that we are the center of all things, either physically at the literal center, or metaphorically as in, we are the most important things in the universe. This is a childish view, held by our ancestors because they couldn’t know any better. Science, as Stephen Gould noted, is partly a process of smashing pillars of human narcissism. Neither the earth, nor our sun, nor our galaxy are at the center of the universe. The universe, it turns out, has no center. Neither are humans at the pinnacle of the evolutionary tree – we are just one twig, and every other twig has just as much evolutionary history behind it as we do.

Humans are certainly the most encephalized species on the planet, with by far the most advanced culture and technology, so we are special in that sense. Every time, however, scientists believe they have nailed down something that is unique about humans, some researcher finds that chimps (our closest cousins), or even other species, can do it too. We are part of the animal kingdom, part of this physical world, the result of natural processes that seem ubiquitous throughout the universe.

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Jun 20 2014

Inflation Evidence Questioned

Published by under Astronomy

A critical part of skeptical outreach is teaching the public about how science works. Surveys of scientific literacy generally have dismal outcomes, but they also generally focus on knowledge about the findings of science, and not so much on the process of science. My personal experience from engaging with the public in multiple venues over decades is that those who are critical or suspicious of science generally are laboring under a gross misunderstanding of how science operates.

Actually it’s not quite accurate to talk about “science,” and that is not how I think about or evaluate scientific claims. Rather, the global scientific community has a certain culture and norms of acceptable behavior. Each country, however, has their own subculture and may have problems or failings specific to them. China, for example, apparently can only publish positive studies about acupuncture, betraying a national bias that calls into question any acupuncture study originating from that country.

Each scientific discipline also has its own subculture. Some professions and specialties are more rigorous than others. Further, each institution, lab, and researcher has their own culture and behavior.

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Jun 09 2014

Origins of the Moon

Published by under Astronomy

What do Theia, Vulcan, Nibiru, Phaëton, and Antichthon have in common? They are all hypothetical planets that do not currently exist. Antichthon is the “counter-Earth” – a planet claimed to be in the same orbit as the Earth but always on the opposite side of the sun, so we can’t see it.  We know Antichthon does not exist because its gravity would be apparent.

Phaëton was the hypothetical planet between Mars and Jupiter that broke apart to form the asteroid belt. Phaëton likely never existed, and the asteroid belt simply failed to ever form a single planet. Nibiru is the planet, not taken seriously by any scientists, that some believe will collide with the Earth sometime this century (predictions have already failed multiple times). Vulcan was hypothesized to orbit within the orbit of Mercury, invented to explain anomalies in the orbit of Mercury that were later explained by general relativity.

Theia is unique among this list of hypothetical planets in that it probably actually existed. It was the Mars-sized planet that struck the proto-Earth 4.5 billion years ago, creating the current Earth-Moon system. This is, at least, the currently most accepted theory of the origin of the moon. It is supported by computer models, and explains many observations about the moon.

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Mar 21 2014

A Scientific Black Hole

Published by under Astronomy

I only have time for a quick post today, so I am going to pig pile on what is likely the most scientifically illiterate thing uttered on television this week.

CNN’s Don Lemon asked his panel of experts if it is preposterous to speculate that a black hole might have sucked in Malaysian flight 370. Let that sink in for a moment.

He actually started out OK, saying it is preposterous, but then felt it was necessary to ask his panel for confirmation. Many will point out that this kind of mindless banter is a symptom of 24 hour news shows that have to fill air time with talking heads.

Shockingly, this was not the most scientifically illiterate thing uttered on CNN this week. The response from Mary Schiavo, I think, wins the award. She is a former Inspector General for the U.S. Department of Transportation. Her response was that even a small black hole would suck in the entire universe, so we know it wasn’t that.

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Feb 21 2014

Pareidolia Watch – Mercury Edition

I only have time for a quick entry today, so here is any easy one - another example of pareidolia unrestrained by reality testing. Pareidolia is the tendency for our brains to match known patterns to random sensory noise, most commonly applied to images. The most familiar image to the human brain is the human face, and so perhaps the most common experience of pareidolia is the seeing of a face in the clouds, in a rust stain, tree bark, tortilla shell, a hillside, or on NASA photos of other worlds.

The Face on Mars is a famous example. Low resolution images of the Cydonia region of Mars showed an apparent face, although the image was lit from the side so half the “face” was missing, and the nostril (which added to the overall illusion) was just data loss from the image. Later higher resolution images showed the face for what it was, just another natural formation.

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Nov 18 2013

MAVEN

Published by under Astronomy

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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