Summer Hits: Martian Water, Asteroid Nukes, Orbital Antimatter!

1 10 2011

Here’s a recap of some of this summer’s greatest hits in space news that you might have missed:

Water on Mars

Dark streaks as summer flow features in Newton Crater, Mars. (Credit: NASA)

In an utterly tantalizing development, scientists analyzing imagery from the Mars Reconnaissance Orbiter (MRO) have announced what appears for all the world to be direct evidence of water on Mars!

Because the MRO has been orbiting the Red Planet since 2006, it has been able to view the same portions of the world at different times of year with an eye toward spotting any potential seasonal changes.  This past August, the MRO team reviewing this growing dataset hit paydirt.

Specifically, the team identified dark streaks on the slopes of steep terrain in the southern hemisphere that are found during Martian spring and summer; these features disappear during Martian winter only to return once again the following spring.

While there are multiple possible explanations, the most likely amongst them appears to be the flow of briny (salty) groundwater that warms in the hotter months, breaches the surface, and evaporates/sublimates as it flows downhill.

Time will tell on this one, but all eyes should be on the possibility of subsurface briny Martian aquifers!

Russian “Armageddon”

Asteroid impact as depicted in the film "Deep Impact." (Credit: Paramount/Dreamworks)

This past August, Russian scientists took a note from Hollywood and seriously proposed the use of nuclear weapons as a means of asteroid mitigation.

Under the scenario, a dual-spacecraft architecture would be employed, with one spacecraft, called “Trap,” ferrying a nuclear warhead to the target while a second spacecraft, “Kaissa,” (apparently and intriguingly named after the mythical goddess of chess,) analyzes the target asteroid’s composition to determine the appropriate warhead use scenario (deflection vs. break-up).

The spacecraft would be lofted by a Soyuz-2 rocket and/or Russia’s upcoming Rus-M rocket.

While much contemporary research casts doubt on the ultimate effectiveness of a nuclear detonation in such a context, the proposers stressed that the technique would only be used on approaching objects up to 600 yards in diameter.

Orbital Antimatter Belt

Antiprotons trapped in the Earth's magnetic field (in pink). (Credit: Aaron Kaase/NASA/Goddard)

Also this past August, researchers published a stunning (but in retrospect, sensible) discovery in Astrophysical Journal Letters: Earth possess a natural orbiting belt of concentrated antiprotons.

Succinctly, the interactions of high-energy cosmic radiation with the Earth’s atmosphere can produce infinitesimal and ordinarily short-lived bursts of antimatter.  These antiparticles normally react with standard matter present around the Earth and annihilate.

However, in the near-vacuum of space beyond the bulk of the Earth’s atmosphere, some of these antimatter particles are spared immediate destruction.  Many of these antiprotons are then herded by the Earth’s magnetic field into bands or belts, which were recently discovered by the antimatter-hunting satellite PAMELA.

Aside from the “gee-whiz” factor, there are certain technical and economic reasons to get excited about the finding.  For starters, the energy density of antiprotons is on the order of a billion times greater than conventional chemical batteries.  However, at a current production cost on Earth of nearly $63 trillion per gram, antiprotons are a bit hard to come by and even less practical to use for anything other than research; Identifying a natural reservoir such as, say, a naturally-produced orbiting belt could open up additional avenues of use for antimatter as well as be immensely lucrative… if only one could solve the lightning-in-a-bottle problem of antimatter storage.

In any case, this is definitely something to keep an eye on.  For the less techno-jargon-inclined, news reports on the find may be found from the BBC as well as Science Magazine.

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“Planet X” lost in space?

29 09 2010

Where is Planet X? It may have escaped the solar system or may not exist at all, say fossil researchers. (Credit: Ben McGee)

Researchers at the University of Kansas and the Smithsonian Institute have performed one of the most extensive analyses of Earth’s past extinction patterns to date.  So, what did researchers Adrian Melott and Richard Bambach conclude?  Planet X cannot exist.

Planet X, also known as Nemesis, is a proposed “dark” (i.e. dim) companion star to the sun, such as a red dwarf or brown dwarf, that sits at an extreme distance and orbits once every 26-million years or so (see other related Planet X blogs here and here).  Conventional Nemesis theory holds that as Nemesis is knocked around by the gravity of nearby stars in the galactic plane, the dark star perturbs the Solar System’s Oort cloud, a shell of icy fragments surrounding the solar system, and sends a shower of comets into the solar system, causing impacts and ultimately – extinctions.

The problem that Melott and Bambach found is that:

  1. According to galactic gravity fields, Nemesis cannot have an exceedingly stable orbit,
  2. The extinction patterns in the fossil record are too regular to be caused by something orbiting the way Nemesis would.

The Solar System moves up and down through the galactic plane as it orbits the Milky Way, carrying the Earth and other planets, (and Nemesis if it is there) along with it.  Well, this up-and-down motion can be roughly measured and tells us that the Solar System passes through the galaxy’s plane less than twice every 54-million years.  If true, that means a perturbation of the Oort cloud because of Nemesis interacting with the galactic plane once every 27-million years doesn’t line up quite right.

This difference was brought into sharp relief by Melott and Bambach, who measured the regularity of fossil record extinctions with meticulous detail using multiple methods, and they found that the period of extinctions is too sharp.  They suggest looking for alternate mechanisms to explain these surprisingly regular apocalyptic events.

So, is Planet X gone?  Another possibility is that we lost it.

If Nemesis’s orbit were too unstable, being perturbed by nearby stars as the Solar System passes through the galactic plane, (think having someone push you regularly on a swingset,) eventually it achieves an escape trajectory and becomes “unbound” – a rogue star in the galaxy no longer gravitationally-linked to us.

In that case, we’d never know – a free dwarf star in the interstellar medium is extremely difficult for astronomers to find.  (i.e., currently impossible.)

So, in an ironic twist, has the Nemesis theory been destroyed by the extinction record that engendered it?

Only time will tell.





Humanity’s outpost in the sky

8 09 2010

ISS and Atlantis (docked) visible in front of the Sun as seen from Earth. 05/22/2010. (Credit: Thierry Legault)

A short note this morning on humanity in the cosmos.  In the above image, an outstanding French photographer managed to capture what otherwise would have whipped by in the blink of an eye.

Crop of the ISS and Atlantis (docked) in front of the Sun. (Credit: Thierry Legault)

For an instant on May 22nd, the International Space Station (ISS) and the docked Atlantis orbiter (space shuttle) moved between Earth and the Sun as they screamed past at colossal orbital speed (16,500 miles per hour).  Rapid photography, meticulous planning, and much skill managed to catch the fleeting moment.

(The ISS and shuttle are visible to the left of the Sun’s center, with the station’s long pairs of solar panels bracketing the shuttle on the left-hand side, its nose angled away.)

My point in posting this morning, aside from sharing the epic “gee-whiz” factor implicit in this photograph, is to try and bring home something about scale, the cosmos, and our place in it.

While looking at the awe-inspiring photo, try to realize that the point of view of the photo -the Earth’s surface- is nearly 250 miles away from the ISS, but the Sun’s backdrop is a full 93 million miles behind it.

Think about that for a moment.  Another way of looking at it is that the ISS is nearly 360 feet wide.  The sun behind it is 4,567,200,000 feet wide, (or 865,000 miles in width, more than 100 Earths across.)  How big is that?  How far away does that have to be?

-That’s like holding out a matchbox car at arm’s length in California and having it be dwarfed by something sitting in Russia.

The ISS, taken from Atlantis as it undocked on May 23, 2010. (Credit: NASA)

When looking at the photo and realizing this immense reality of scale, the ISS’s cosmic ranking starts to come into perspective.  Even considering that the ISS is likely the most ambitious international effort ever attempted, (and by logical extension, arguably humanity’s most collectively ambitious project to date,) it is still clearly just the beginning of humanity’s toe-hold on the rest of the cosmos.

Space is big. You just won’t believe how vastly, hugely, mind-bogglingly big it is.  (Thanks, Douglas…)  Ahem..

But seriously, maybe by looking at images like the above transit image by Theirry Legault and forcing your brain to accept what it knows to be true – that the station and all of its habitable space (roughly comparable to a 3,000 square-foot house) is just a speck, our entire Earth could be swallowed whole by the Sun without it even noticing, and our Sun is just a mediocre star amongst billions of burning brothers in the cosmos – we’ll all come to realize that we should really start moving out into the rest of the universe… just for safety’s sake.

We’re obviously really significant to ourselves.  Yet, to 99.999% of the rest of the universe, we haven’t even gotten into little league.  Metaphorically, no one knows we exist yet, and minor league players out there like asteroids and comets, (not to mention major league events like nearby supernovas,) can still easily wipe us out.

So, if we want a shot at winning the world series someday, (interpret the cosmic meaning of this increasingly threadbare analogy as you will,) we’d better start playing ball.

 

Artificial gravity and large-scale settlement space station designed by Wernher Von Braun. (Credit: Courtesy NASA/MSFC Historical Archives)





Two small asteroids bulls-eye between Earth and Moon tomorrow!

7 09 2010

Asteroids 2010 RF12 and 2010 RX30 to narrowly miss Earth. (Credit: Ben McGee)

Note: Two asteroids, roughly 30-feet-across and 60-feet-across, will zing between the Earth and the Moon sometime tomorrow, as reported by AstronomyNow.  Nothing to be alarmed about, as these guys are small enough that if they hit Earth, they’d burn up and become a “shooting star.”  However, it is noteworthy that the two ancient rocks, named “2010 RF12,” and, “2010 RX30,” both pass within the distance separating the Earth and Moon.

Fun to know what’s going on in our neighborhood.





Astrowright Academy and the Classroom of Tomorrow

23 08 2010

Well, just a quick note this morning.  Today is my first day of class as a graduate student in the University of North Dakota’s School of Aerospace Sciences Department of Space Studies program.

So, you could say that my advanced academic push toward becoming an astrowright has begun.  -And in true 21st Century form, as I commute to work, I’ll actually be “attending” a lecture.

University of North Dakota SpSt 541 class lecture #2. Credit: Me.

Here goes nothing.





Titan eclipses Mars

22 08 2010

Cassini spacecraft view of Saturn's 3200-mile-wide moon, Titan, with the smaller, 698-mile-wide moon Dione actually 600,000 miles behind it. Credit: NASA/JPL/Space Science Institute

Titan has eclipsed Mars.  Not literally, mind you, but conceptually.  With active surficial geology the likes of which are known only to Earth, and considering the recent discovery of possible biochemical signatures of alien life, to me Titan has become the most interesting exploration destination in the solar system.

Take the above image, for starters.  Whereas most other rocky worlds in our solar system offer an unbridled view of craters, mountains, and ancient plains, Titan’s dynamic, hazy atmosphere betrays little.  Truly, the giant moon, which is larger than the planet Mercury itself, is a world shrouded in mystery.

-And, the more we learn about Titan, the more we have reason to believe it is the most Earth-like world this side of a few trillion miles.

(As an aside: My hat is off to the CICLOPS Cassini spacecraft imaging team for giving us real-life pictures like this.  Thanks to them, images from our science today trump the science fiction special effects of a decade ago.)

Unlike Mars, Titan offers us lakes, rivers, clouds, and rain – A full, living hydrologic cycle that is active not billions of years ago, but today.  (Yes, “hydrologic cycle” is perhaps a slight misnomer, because on Titan the active fluid is methane/ethane, not H2O, but the process appears to be the same.)  -And, perhaps most excitingly, scientists have recently discovered evidence that may indicate methane-based alien biochemistry at work.

Specifically, a flux of hydrogen molecules toward Titan’s surface, (rather than away as would be expected,) may indicate the consumption of the gas on Titan (as aerobic life on Earth consumes oxygen); A distinct lack of the hydrocarbon acetylene, one of the most potent chemical energy sources on Titan, may betray that hydrogen-breathing, methane-based life is consuming acetylene as food.

And at least hypothetically, all of the potential chemistry checks out.

If all of this together doesn’t spell impetus for further investigation, I can’t imagine what does.  To boot, because it is so cold out at Saturn’s distance from the Sun and despite Titan’s weaker gravity, the condensed atmospheric pressure on Titan is practically identical to what we experience on Earth, making human exploration all the more feasible.

Have spacesuit, will travel.  Titan or bust.





Differences between SETI, Astrobiology, UFOlogy

17 08 2010

Based on some recent feedback, I’m tempted to pose a question to the cyberverse:

  • What differences do you see, if any, between SETI (the Search for Extraterrestrial Intelligence), Astrobiology (study of locations and potential biochemistry of extraterrestrial life), and UFOlogy (study of UFOs)?

I ask this as a general point of discussion because some have expressed concern that working toward a preconceived methodology for xenoarchaeology, like I’ve been working on, will confuse Astrobiology, SETI, and the more pseudoscientific UFOlogy in the public mind.

So, what do you think?  Just how different is your perception of SETI, Astrobiology, and UFOlogy?  How legitimate a scientific pursuit are each?  How illegitimate?

Clearly, all three concepts are related.  Without Astrobiology, SETI and UFOlogy cannot logically exist.  UFOlogy implies “ETI,” but it makes some pretty incredible assumptions that in my mind remove it from the realm of hard science, or even speculative science, for that matter.

So, have at it.  Comments welcome.








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