Tag: Space

Sciency Words: Degeneracies

~ J.S. Pailly ~ 2 Comments

Today’s post is part of a special series here on Planet Pailly called Sciency Words.  Each week, we take a closer look at an interesting science or science-related term to help us expand our scientific vocabularies together. Today’s term is:

DEGENERACIES

Okay, I have to be honest with you: I really don’t understand what this term means.  It’s a statistics thing, and it gets really mathy.  But since I came across this term in a paper about the TRAPPIST-1 planets, I felt I should try to get some sense of what a degeneracy is.  What I learned, at least in relation to planets, was interesting enough that I thought it was worth sharing with you.

Imagine we’re playing a game of “Guess Who?”  You know my person has red hair, but you still don’t know my person’s age or gender, you don’t know if my person is wearing glasses, or if my person has freckles.  That one datapoint—my person has red hair—eliminates a lot of possibilities from the board, but there are still plenty of possibilities left over.

Those left over possibilities can be refered to as degeneracies (if I’m understanding the proper usage of this term).  In that paper on the TRAPPIST-1 planets, it says: “The derivation of a planetary composition from only its mass and radius is a notoriously difficult exercise because of the many degeneracies that exist.”

In other words, if you’re playing “Guess Who?” with planets, knowing a planet’s mass and volume (and thus being able to calculate its density) still leaves you with a whole lot you don’t know about that planet.

This reminds me a lot of the Earth Similarity Index and the problems with using that system to identify Earth-like planets. Venus, for example, scores rather highly on the E.S.I. because its mass and volume are so similar to Earth’s, but Venus is not at all Earth-like in the sense that most people mean when they talk about Earth-like planets.

I’d say I plan to study this concept more, but I think I’m done for now.  I tried to read this paper from 2010 which seems to have introduced the subject of degeneracies to planetary science and warned that they’d be a real problem in the study of exoplanets.  But after attempting to slog my way through that paper, I think I’ve had enough mathy stuff for a while.

TRAPPIST-1: Too Much Water to Support Life?

~ J.S. Pailly ~ 6 Comments

I’m still catching up on my research after having something of a rough start to the year.  A few months ago, I saw headlines saying that water had been discovered in the TRAPPIST-1 system.  A whole lot of water.  Too much water, in fact.  Normally where there’s water there could be life, but according to the news articles I read back in February, the TRAPPIST-1 planets have so much water that life probably could not exist there (not enough carbon, not enough minerals).

Bummer.

But now I’ve finally read the actual research, and I’m really glad I did because a lot of journalists in the popular press clearly did not.  This paper, titled “Inward Migration of the TRAPPIST-1 Planets as Inferred From Their Water-Rich Compositions,” ends thusly:

[…] while these planets may be habitable in the classical definition, any biosignature observed from these planets system may not be fully distinguishable from abiotic, purely geochemical sources.  Thus, while M-dwarfs may be the most common habitable planet-host in our Galaxy, they may be the toughest on which to detect life.

In other words, these planets very well might be able to support life, but we may not be able to detect that life if it’s there.

This reminds me of a paper Carl Sagan wrote in the 1990’s showing how difficult it is to conclusively prove there is life on Earth based solely on observations made by a passing NASA spacecraft.

Earth’s oceans in particular do an outstanding job masking the usual biosignatures we would be looking for.  As far as that NASA spacecraft could tell, Earth’s oceans appeared to be completely lifeless.

So if the planets of the TRAPPIST-1 system really are as that inward migration paper describes them—15% to 50% water, with their surfaces covered entirely by ocean—then we are going to have a really difficult time finding life there.  But that is not the same as saying there’s no life there to find!

Sciency Words: Nice Model

~ J.S. Pailly ~ 5 Comments

Today’s post is part of a special series here on Planet Pailly called Sciency Words.  Each week, we take a closer look at an interesting science or science-related term to help us expand our scientific vocabularies together.  Today’s term is:

NICE MODEL

I recently assembled Lego’s Saturn V rocket set, and I have to say it’s a really nice model.  It even has these little orange pieces to represent the floaty things for when the Apollo capsule returns to Earth and splashes down in the ocean. That, I thought, was a really nice touch!

But as nice as that Lego model is, that’s not the model we’re talking about today.  Nope, today we’re talking about the Nice model, with a capital N.

In May of 2005, three papers were published in the journal Nature which did a nice job explaining some of the big mysteries of our Solar System.

  • First (in order of page number) was a paper on the anomalous orbital eccentricities and inclinations of the four gas giant planets.
  • Next came a paper on the Trojan asteroids which hang out around Jupiter’s Lagrange points, 60º ahead and 60º behind Jupiter in its orbital path.
  • And lastly, there was a paper on the Late Heavy Bombardment, a period of time when the Moon (and also the four inner planets) got pummeled with asteroids.

All three of these papers share a common idea: that the four gas giants of our Solar System must have started out much closer together, with a broad disk of rocky and icy debris beyond them, like a super-sized Kuiper belt.  Then, approximately 700 million years after their initial formation, three of those gas giants (Saturn, Uranus, and Neptune) started drifting farther and farther away from the Sun and away from each other.

Jupiter seems to have drifted slightly closer to the Sun, but stopped short of entering and demolishing the inner Solar System thanks to a last minute gravitational interaction with Saturn (thanks, Saturn!).

As the gas giants spread out, they threw that super Kuiper belt into chaos.  Some of that rocky and icy debris was hurled toward the inner planets, causing the Late Heavy Bombardment.  Some of the debris got stuck around Jupiter’s Lagrange points, becoming the Trojan asteroids.  And with so many complicated gravitational interactions happening at once, it’s no wonder the four gas giants ended up with some anomalies in their orbital paths.

This one idea—that the gas giants drifted apart after they formed—does a pretty nice job explaining three of the biggest mysteries about our Solar System.  But sadly, that’s not why it’s called the Nice model.  The name actually isn’t pronounced like the English word “nice” but rather like the French city of Nice (which rhymes with geese or fleece).  That’s because the model was originally formulated at an observatory in Nice, France.

Unfortunately, I didn’t find that out until I’d already sprinkled a bunch of nice puns into this post, and I don’t feel like taking them out.

The End for Juno?

~ J.S. Pailly ~ 6 Comments

We’ve always known the Juno Mission to Jupiter would be a short one.  Often times planetary science missions like Juno will get extra funding for extended missions, because it costs less to keep using a spacecraft you already have than it does to design, build, and launch a new one.  But as I wrote two years ago, this really wouldn’t be an option for Juno.

The reason is that Jupiter has at least one moon (Europa) and perhaps two others (Ganymede and Callisto) which may be home to alien life.  Based on everything I’ve read about Europa in particular, I think it would be a bigger surprise if we didn’t find life there; that’s how promising the place looks.

NASA absolutely cannot risk letting Juno crash into and contaminate any of those moons (especially Europa).  So after completing its scheduled mission, which was meant to take about two years, Juno would do a suicide run into Jupiter’s atmosphere, destroying itself to ensure there are no future accidents, and also collecting a little extra atmospheric data in the process.

Except shortly after Juno arrived in Jupiter orbit, it ran into some engine trouble, something to do with a pressure valve opening too slowly. As a result, Juno wound up stuck in a much wider and much longer orbit than originally planned.  Rather than getting a science pass every 14 days, we’re getting them every 53 days, which has dramatically slowed down Juno’s progress.

Juno’s two years are almost up, but because of that pressure valve malfunction its mission is only half complete.  So now Juno needs that mission extension that it was never supposed to get.  A planetary scientist working on the Juno Mission was recently quoted as saying: “I think for sure the continuation mission will go on.”  He then added: “I’m hopeful but nervous.”

Funding for the Juno mission (for ground operations, mission control stuff, etc) will run out in July of this year. Given the circumstances, I have to assume NASA will grant Juno an extension, but as of this writing they have not done so.  Navigating the bureaucracy here on Earth can be just as nerve-wracking as all the hazards of space.

I’m not sure how much Congress is involved in the decision making process here, so maybe that’s what’s holding things up. Or maybe Juno has run into other technical issues which NASA hasn’t made public yet.  I don’t know, but if anything else went wrong with the spacecraft during its extended mission, we might lose control of it, and we really, really do not want it crashing into those icy-on-the-outside, watery-on-the-inside moons.

So fingers crossed.  Hopefully everything works out okay and Juno can get its extended mission.

Sciency Words: Voorwerp

~ J.S. Pailly ~ 5 Comments

Today’s post is part of a special series here on Planet Pailly called Sciency Words.  Each week, we take a closer look at an interesting science or science-related term to help us expand our scientific vocabularies together. Today’s term is:

VOORWERP

In 2007, Dutch schoolteacher and citizen scientist Hanny van Arkel was participating in the Galaxy Zoo project.  She was sorting through photos of galaxies (there are so many galaxies out there, scientists need help sorting through them all) when she came upon the image of a weird, green, blob-like object.

This mysterious object came to be known as Hanny’s Voorwerp, because voorwerp is the Dutch word for object.

Image courtesy of Wikipedia.

It’s hypothesized that the spiral galaxy in the upper part of the image had a quasar flare up at some point.  The resulting super accelerated jets of radiation must have hit a giant dust cloud, which we now see glowing green.

The quasar has since stopped, or at least calmed down for now, but that distinctive green glow can persist for tens of thousands of years. The color is almost certainly caused by ionized oxygen atoms.

Hanny’s Voorwerp is enormous, roughly the same size as our own Milky Way Galaxy.  We now know of several other glowing green blobs hanging around other suspected former quasers.  This paper identifies nineteen of them, and this collage from Wikipedia shows eight.

Image courtesy of Wikipedia.

These are commonly known as voorwerpjes. I have to admit I don’t know anything about Dutch (my linguistic education focused on Latin and Greek), but according to Wiktionary.org the j-part creates a diminutive form.  So Hanny’s Voorwerp is the big “object” and the others are like cute, little “objectlings.”  Well, little on the astronomical scale, at least.

Future research on Hanny’s Voorwerp and those voorwerpjes may tell us more about how quasar activity fluctuates over time. Also, it seems that getting zapped by a quasar may have triggered star formation inside Hanny’s Voorwerp. So we may be witnessing the very, very earliest beginnings of a brand new galaxy.

New Horizons: The Road Goes Ever On

~ J.S. Pailly ~ 9 Comments

The New Horizons mission has been on my mind recently, in part because of my post last week on Ultima Thule, but also because I just started reading Chasing New Horizons: Inside the Epic First Mission to Pluto by Alan Stern and David Grinspoon.

New Horizons has already visited the most distant “planet” in the Solar System (Pluto was still considered a planet when New Horizons launched), and now it’s going to explore an object even more distant than that. And after that?  Onwards to interstellar space, just like Voyager I and Voyager II, to continue exploring the universe for us.

But as I said, all this has got me thinking about travel and exploration and discovery, and also strangely (or perhaps not so strangely) about J.R.R. Tolkien.  So today I’d like to share a piece of Tolkien’s poetry, something that fit nicely into The Lord of the Rings but also fits nicely (I think) into the ongoing saga of the New Horizons mission.

Sciency Words: Ultima Thule

~ J.S. Pailly ~ 7 Comments

Today’s post is part of a special series here on Planet Pailly called Sciency Words.  Each week, we take a closer look at an interesting science or science-related term to help us expand our scientific vocabularies together. Today’s term is:

ULTIMA THULE

It just so happens that the New Horizons space probe, which flew by Pluto in 2015, will pass near another Kuiper Belt Object at the start of 2019—on New Year’s Day, in fact!  And that Kuiper Belt Object is called Ultima Thule (pronounced thoo-lee).

I first heard this name on a podcast called Are We There Yet? (click here, it’s about 20 minutes long), and I was initially confused.  I had thought New Horizons was heading toward an object named MU69; what the heck in an Ultima Thule?  Turns out they’re one in the same.  “(486958) 2014 MU69” is the official name approved by our old friends, the International Astronomy Union (I.A.U.), but NASA recently held a contest to see if the public could come up with something better.

The New Horizons mission team selected “Ultima Thule” as the winner, making it the official unofficial name, if that makes sense. And it’s a good name, a name with a long history going back to medieval times.  Thule was the name for a mythical island that was said to be as far north as you could possibly go, somewhere right at the edge of the world as Mankind knew it.  So Ultima Thule was an even more mythical land somewhere beyond that, beyond the limits of the known world!

The metaphor, I think, is that Pluto is Thule: the most distant planet (sort of) in the Solar System, and now we’re going to a place even farther than that.  Ultima Thule will be the most distant object ever visited by one of our space probes, and it will stretch the boundaries of human knowledge.  So yeah, the name seems appropriate.

But it’s interesting to me that NASA and the New Horizons mission seem to have picked this name without consulting with the I.A.U. first. They’ve done this sort of thing before, assigning a whole bunch of names to surface features on Pluto, and putting those names into official, scientific documents without asking for the I.A.U.’s permission first.  This reportedly annoyed the I.A.U.  And some of the scientists from New Horizons are still fighting to get Pluto’s planet status back, which I’m sure also annoys the I.A.U.

According to this press release from NASA, the New Horizons mission will submit an official naming proposal to the I.A.U. after the New Year’s Day flyby, once they know exactly what it is they’re naming. I’m guessing the I.A.U. will accept Ultima Thule, but if there does end up being a bit of a spat over this between the I.A.U. and New Horizons team, it wouldn’t surprise me.

Correction: I spent much of New Year’s Eve watching NASA TV, and everyone there pronounced the name as Ultima Too-lee rather than Thoo-lee. So I guess that’s how you say it.

Hooray for Citizen Scientists!

~ J.S. Pailly ~ 6 Comments

In last week’s episode of Sciency Words, we met “Steve” and learned how this strange and unexpected aurora-like phenomenon ended up with such a friendly, normal-sounding name.  But there’s another important aspect of Steve’s story that I didn’t really touch on: the role of citizen scientists.

Photo of “Steve” by Elfie Hall, courtesy of Wikipedia.

Toward the end of this paper from Science Advances, the same paper which linked Steve to another aurora-related phenomenon known as S.A.I.D., I found a paragraph that I feel is interesting enough and important enough to quote in full:

STEVE has highlighted the importance of citizen science.  Although independently observed previously by auroral photographers both amateur and professional, citizen science has proven to be a bridge between amateur observers and traditional aurora scientists.  This bridge has facilitated the advancement of our understanding of both the night sky and magnetosphere-ionosphere coupling.  We emphasize that this collaboration with the citizen scientists was not simply through crowdsourcing and image analysis of a large data set. Citizen scientists discovered a new category of auroral observation by synthesizing complex information and asked the scientific community for input on these observations.  This example can help change the nature of scientific engagement between the scientific community and citizen scientists and move communication from one way to two way, with curiosity transitioning to participation and finally to stewardship.

Citizen science is often portrayed as something new, something that’s only become possible thanks to computers, the Internet, and technology in general.  And I think that’s fair.  The mystery of Steve might not have been investigated as thoroughly as it has been, or it might not have been investigated at all, if not for Facebook.

For most of the 20th and early 21st Centuries, cutting edge science has required a lot of extremely powerful, extremely sensitive, and extremely expensive equipment.  If modern science is seen as inaccessible to the average person, that might be in part because the average person could not afford to perform science him or herself.

But it wasn’t always so.  Most of the great scientists of the 17th, 18th, and 19th Centuries were essentially hobbyists, people who indulged their curiosity using the kind of tools they either bought off the shelf or built with their own hands.

So in a way, I think of citizen science as science returning to its roots, with ordinary men and women contributing once more to the important discoveries of our time (like the discovery of Steve).

Sciency Words: Steve

~ J.S. Pailly ~ 2 Comments

Today’s post is part of a special series here on Planet Pailly called Sciency Words.  Each week, we take a closer look at an interesting science or science-related term to help us expand our scientific vocabularies together. Today’s term is:

STEVE

In 2014, photographer, citizen scientist, and weather enthusiast Chris Ratzlaff was out looking for the aurora borealis when he saw something weird in the sky.  Something that looked like an aurora but could not possibly be an aurora.

For one thing, it was in the wrong part of the sky.  It was too far south, well outside the auroral oval, the region encircling the pole where, on any given night, aurorae are predicted to occur.

And for another thing, this mysterious something was the wrong color.  It was purple. Now I was a bit confused about this part at first, because I thought purple was one of the normal colors in an aurora (along with green).  But aurora purple is more of a reddish or magenta-ish purple, whereas this new phenomenon was a true purple.  A purplish purple, so to speak.

According to this interview with Canadian Geographic, Chris shared pictures of the whatever-it-was on a Facebook group called Alberta Aurora Chasers.  Other members of the group then went out and got more photos.  Hundreds of photos.  And time-lapse sequences.

But still, nobody knew what this purple thing was.  An early guess that it was something called a proton arc got shot down by an expert, at which point Chris wrote “[…] until we know what it is, let’s call it Steve.”  This was a reference to the DreamWorks Animated film Over the Hedge.

In the film, a group of animals are confused and alarmed by the appearance of a neatly-trimmed hedge.  One of the animals says, “I would be a lot less afraid of it if I just knew what it was called,” to which another animal replies, “Let’s call it Steve!”


This bit about being less afraid of a thing simply because you know its name is, in my view, a profoundly true statement about the power of language.  But I digress.

According to this research paper from Science Advances, we now know, thanks to all those photos and time lapses from the ground, combined with satellite observations from orbit, what “Steve” is.  Or at least we know that it’s associated with another phenomenon called an S.A.I.D. (SubAuroral Ion Drift). Thanks to Steve, we now have a new way to observe and study S.A.I.D.s and learn more about the interaction between the solar wind and Earth’s magnetic field.

As such, Steve has been assigned a more proper-sounding scientific name: Strong Thermal Emission Velocity Enhancement (or S.T.E.V.E. for short).

Didymos, Didymoon, and Didy-me

~ J.S. Pailly ~ 13 Comments

I’m a huge space enthusiast and science enthusiast, but I am not an actual scientist.  I’m an outsider looking in, drooling a little as I watch all those real scientists doing all that real science.  But even as an outsider, I still sometimes get the chance to contribute in my own small way to the cause of science and space exploration.

Coming up in June of 2018, the Didymos Observer Workshop will be held in Prague, Czeck Republic.  For those of you who don’t recognize the name, Didymos is a large asteroid with an orbit that sometimes brings it alarmingly close to Earth.  It’s also one of those asteroids that has its own tiny moon, a moon which is informally known as “Didymoon.”

The Didymos Observer Workshop will be discussing the upcoming AIDA mission, a joint venture between NASA and ESA.  According to the workshop’s website, “AIDA will be the first space experiment to demonstrate asteroid impact hazard mitigation by using a kinetic impactor to deflect an asteroid.”  In other words, we’re going to whack Didymoon really hard to see how much we can change its orbit around Didymos.

Honestly, I feel a little bad for Didymoon, but the results of this experiment will help us prepare for the day when we need to smack an incoming asteroid off of a collision course with Earth. This is important for science, and someday it may save a whole lot of lives.

And I am really, really proud to say that one of my drawings is being used (with permission, of course) in the Didymos Observer Workshop’s promotional material.  Click here to check it out!