Posts about space

Very Low Frequency Radio Waves Protect Earth

Very Low Frequency (VLF) radio communications signals are transmitted from ground stations at huge powers to communicate with submarines deep in the ocean. While these waves are intended for communications below the surface, they also extend out beyond our atmosphere, shrouding Earth in a VLF bubble. This bubble is even seen by spacecraft high above Earth’s surface, such as NASA’s Van Allen Probes, which study electrons and ions in the near-Earth environment.

The probes have noticed an interesting coincidence — the outward extent of the VLF bubble corresponds almost exactly to the inner edge of the Van Allen radiation belts, a layer of charged particles held in place by Earth’s magnetic fields. Dan Baker, director of the University of Colorado’s Laboratory for Atmospheric and Space Physics in Boulder, coined this lower limit the “impenetrable barrier” and speculates that if there were no human VLF transmissions, the boundary would likely stretch closer to Earth. Indeed, comparisons of the modern extent of the radiation belts from Van Allen Probe data show the inner boundary to be much farther away than its recorded position in satellite data from the 1960s, when VLF transmissions were more limited.

With further study, VLF transmissions may serve as a way to remove excess radiation from the near-Earth environment. Plans are already underway to test VLF transmissions in the upper atmosphere to see if they could remove excess charged particles — which can appear during periods of intense space weather, such as when the sun erupts with giant clouds of particles and energy.

Related: NASA’s Van Allen Probes Spot Man-Made Barrier Shrouding EarthAstronaut SelfieMagnetic Portals Connect Sun and Earth (2008)Webcast of Man Landing on the MoonNASA Biocapsules Deliver Medical Interventions Based Upon What They Detect in the Body (2012)

Solar Storm Could Do $2 Trillion in Damage

I read an interesting article from NASA recently, Near Miss: The Solar Superstorm of July 2012

According to a study by the National Academy of Sciences, the total economic impact could exceed $2 trillion or 20 times greater than the costs of a Hurricane Katrina. Multi-ton transformers damaged by such a storm might take years to repair.

By extrapolating the frequency of ordinary storms to the extreme, he calculated the odds that a Carrington-class storm would hit Earth in the next ten years.

The answer: 12%.

Our high technology is far more at risk than most people appreciate. I don’t understand why the odds are so high (given that the last such event was in 1859 but I would guess there are sensible reasons for them to calculate such high odds. Others (in a quick web search) offer lower odds, but still 7 or 8% of such an event in the next 10 years.

The 2012 event would have done a great deal of damage. Luckily it was directed away from the sun in a direction away from where the earth was at the time. NASA has satellites arrayed around the sun (even where the earth isn’t) and one of those was able to capture data on the event.

There is also disagreement about how much damage such a solar storm would cause on earth. The main direct damage is expected to be done to the power system (of the USA and the rest of the world).

Related: Solar Storm (2006)photo of Solar Eruption (2006)Solar Flares May Threaten GPS (2007)Magnetic Portals Connect Sun and Earth (2008)

NASA explored this idea in a webcast:

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Female African-American Mathematicians at NASA in 1961

Hidden Figures is a film based on the experiences of female African-American mathematicians at NASA in 1961 including Katherine Johnson. It is easy to forget our history if we don’t make an effort to remember.

Popular movie adaptations are not the best source for completely accurate history but they are a great way to raise awareness when they hold somewhat close to historical events.

It is amazing to see what was accomplished and also remember how badly mistaken our society was in important ways. We have made strides as a society, but we still have significant problems we need to address. Movies like Hidden Figures are a positive reminder of what can be accomplished when we give people opportunities. We need to remember that lesson and do what we can to remove the barriers that continue today.

NASA video on Katherine Johnson’s career:

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Computer Code for NASA’s Apollo Guidance System

photo of Margaret Hamilton, NASA

Margaret Hamilton, NASA. Standing next to a printout of the source code she and her team wrote for the Apollo guidance computer that made the moon landings possible.

Meet Margaret Hamilton, the badass ’60s programmer who saved the moon landing

The software for the guidance computer was written by a team at the MIT Instrumentation Laboratory (now the Draper Laboratory), headed up by Margaret Hamilton.

The guidance computer used something known as “core rope memory“: wires were roped through metal cores in a particular way to store code in binary. “If the wire goes through the core, it represents a one,” Hamilton explained in the documentary Moon Machines. “And around the core it represents a zero.” The programs were woven together by hand in factories. And because the factory workers were mostly women, core rope memory became known by engineers as “LOL memory,” LOL standing for “little old lady.”

Hamilton is now 78 and runs Hamilton Technologies, the Cambridge, Massachusetts-based company she founded in 1986. She’s lived to see “software engineering” — a term she coined — grow from a relative backwater in computing into a prestigious profession.

In the early days, women were often assigned software tasks because software just wasn’t viewed as very important. “It’s not that managers of yore respected women more than they do now,” Rose Eveleth writes in a great piece on early women programmers for Smithsonian magazine. “They simply saw computer programming as an easy job. It was like typing or filing to them and the development of software was less important than the development of hardware. So women wrote software, programmed and even told their male colleagues how to make the hardware better.”

My aunt was one of those early software engineers. She wrote a chapter for a book, Programming the IBM 360, in the 1960s. My uncle was one of the first employees at NASA and rose to be one of the senior administrators there over his career.

It is great when society is able to capture the value individuals are capable of providing. We need to make sure we allow everyone opportunities to contribute. We do well in many ways but we also do lose from discrimination and also just making it uncomfortable for people to contribute in certain roles when we need not do so.

We have accomplished great things with software in the last 40 years. We could have accomplished more if we had done a better job of allowing women to contribute to the efforts in this field.

Related: The Eagle Has LandedBarbara Liskov wins Turing AwardGreat Self Portrait by Astronaut with Earth Reflected in His Visor

Why is the Sky Dark at Night?

The answer isn’t quite as simple as it seems. I find the wording in the video a bit confusing.

The point I believe, is that the sky is dark instead of light. But not that the brightness would be huge (so for example, you couldn’t necessarily read my book outside just by starlight). The light would be very faint, it is just that it would be lightish instead of blackish, due to the reasons explained (redshift etc.). At least that is my understanding.

Related: Why is it Colder at Higher Elevations?Why Does the Moon Appear Larger on the Horizon?Why is the Sky Blue?Why Wasn’t the Earth Covered in Ice 4 Billion Years Ago – When the Sun was Dimmer

Did a massive comet explode over Canada 12,900 years ago and start an ice age?

I think it is important to increase scientific literacy. One thing that is greatly misunderstood is the process for new scientific explanations being accepted by the scientific community. It is often quite a drawn out process over years (and for the explanation provided in this paper the debate is certainly still ongoing). And for issues that really shake up past explanations it can take decades and be quite contentious. I think posts tagged with “scientific inquiry” are a very interesting collection to explore.

It is important to understand the difficulty in providing evidence that satisfies the overwhelming majority of the scientific experts in any area. And it is important to understand the claims in one (or numerous papers) are not the accepted proven wisdom of the scientific community. Thankfully the process is rigorous. While mistakes can still be made, the evidence needed to substantiate a scientific hypothesis is significant. Their is still plenty of room for position to color accepted scientific wisdom. A respected professor is often able to make a claim that is more readily accepted and even more-so for to insist the new claims do not provide enough evidence in support of them to accept the new claims and have there position accepted (even when it really shouldn’t be looking just at the facts).

Topper site in middle of comet controversy

Firestone found concentrations of spherules (micro-sized balls) of metals and nano-sized diamonds in a layer of sediment dating 12,900 years ago at 10 of 12 archaeological sites that his team examined. The mix of particles is thought to be the result of an extraterrestrial object, such as a comet or meteorite, exploding in the earth’s atmosphere. Among the sites examined was USC’s Topper, one of the most pristine U.S. sites for research on Clovis, one of the earliest ancient peoples.
“This independent study is yet another example of how the Topper site with its various interdisciplinary studies has connected ancient human archaeology with significant studies of the Pleistocene,” said Goodyear, who began excavating Clovis artifacts in 1984 at the Topper site in Allendale, S.C. “It’s both exciting and gratifying.”
Younger-Dryas is what scientists refer to as the period of extreme cooling that began around 12,900 years ago and lasted 1,300 years. While that brief ice age has been well-documented – occurring during a period of progressive solar warming after the last ice age – the reasons for it have long remained unclear.

Related: Why Wasn’t the Earth Covered in Ice 4 Billion Years Ago – When the Sun was Dimmer?Unless We Take Decisive Action, Climate Change Will Ravage Our PlanetMore Evidence Supporting Einstein’s Theory of GravityAncient Whale Uncovered in Egyptian Desert

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The Eagle Has Landed

Neil Armstrong and Buzz Aldren land on the moon: July 20, 1969. As Neil Armstrong took humanity’s first step onto the Moon he said:

That’s one small step for man, one giant leap for mankind.

Related: Experiment, dropping a hammer and feather on the MoonPlanetary scientist Jennifer Heldmann discusses the MoonApply to be an AstronautOne Giant Leap For Mankind

Landing Curiosity on Mars

Touchdown on Mars will take place August 5th, 2012 (PDT or August 6th EDT and GMT).

Related: NASA’s Mars Curiosity RoverMars Opportunity Rover Continues Extended ExplorationSunset on Mars

Scientific Inquiry Process Finds More Evidence Supporting Einstein’s Theory

As scientists have been able to see farther and deeper into the universe, the laws that govern its expansion have been revealed to be under the influence of an unexplained force.

In a paper on the arXiv, Astrophysical Tests of Modified Gravity: Constraints from Distance Indicators in the Nearby Universe, are a vindication of Einstein’s theory of gravity. Having survived several decades of tests in the solar system, it has passed this new test in galaxies beyond our own as well.

In 1998, astrophysicists made an observation that turned gravity on its ear: the universe’s rate of expansion is speeding up. If gravity acts the same everywhere, stars and galaxies propelled outward by the Big Bang should continuously slow down, like objects thrown from an explosion do here on Earth.

This observation used distant supernovae to show that the expansion of the universe was speeding up rather than slowing down. This indicated that something was missing from physicists’ understanding of how the universe responds to gravity, which is described by Einstein’s theory of general relativity. Two branches of theories have sprung up, each trying to fill its gaps in a different way.

One branch — dark energy — suggests that the vacuum of space has an energy associated with it and that energy causes the observed acceleration. The other falls under the umbrella of “scalar-tensor” gravity theories, which effectively posits a fifth force (beyond gravity, electromagnetism and the strong and weak nuclear forces) that alters gravity on cosmologically large scales.

“These two possibilities are both radical in their own way,” University of Pennsylvania astrophysicist Bhuvnesh Jain said. “One is saying that general relativity is correct, but we have this strange new form of energy. The other is saying we don’t have a new form of energy, but gravity is not described by general relativity everywhere.”

Jain’s research is focused on the latter possibility; he is attempting to characterize the properties of this fifth force that disrupts the predictions general relativity makes outside our own galaxy, on cosmic length scales. Jain’s recent breakthrough came about when he and his colleagues realized they could use the troves of data on a special property of a common type of star as an exquisite test of gravity.

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Video of Young Richard Feynman Talking About Scientific Thinking

The enjoyable video above shows a young Richard Feynman discussing how scientific thinking can advance our understanding of the world.

Related: Feynman “is a second Dirac, only this time human”Science and the Excitement, the Mystery and the Awe of a FlowerClassic Feynman: All the Adventures of a Curious Character

Star Stuff: The Universe is In Us

Great statement from Neil DeGrasse Tyson on “what is the most astounding fact you can share with us about the universe.”

“The atoms that comprise life on earth, the atoms that make up the human body, are traceable to the crucibles that cooked light elements into heavy elements in their core under extreme temperatures and pressures. These stars, the high mass ones among them, went unstable in their later years. They collapsed and then exploded scattering their enriched guts across the galaxy. Guts made of carbon, nitrogen, oxygen, and all the fundamental ingredients of life itself. These ingredients become part of gas clouds that condense, collapse, form the next generation of solar systems: stars with orbiting planets. And those planets now have the ingredients for life itself. So when I look up at the night sky and I know that, yes we are part of this universe, we are in this universe, but perhaps more important than both of those facts, is that the universe is in us… my atoms came from those stars….”

I think this might well be my thought on the most astounding fact also. Ever since I learned the atoms we are made of were created inside stars it has never ceased to amaze me.

Neil DeGrasse Tyson is amazing. I would edit his statement a bit myself, though, to make it:

“The most astounding fact is that the atoms that comprise life on earth, the atoms that make up the human body, were created in the crucible of stars that cooked light elements into heavy elements. Those stars went unstable, in their later years: they collapsed and then explored scattering their enriched cores across the galaxy. Those stars made the carbon, nitrogen, oxygen, and all the fundamental ingredients of life itself. Those ingredients became part of gas clouds that condensed to form the next generation of solar systems: stars with orbiting planets. And those planets have the ingredients for life. So when I look up at the night sky, I know that my atoms came from the predecessors of the stars I see.”

Related: Scientifically Literate People See a Different WorldTen Things Everyone Should Know About ScienceGravity and the Scientific MethodThe Importance of Science Education

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