Well, it’s the end of another week. I’ll save the bigger posts I have planned for next week and instead end with this little astronomy/geometry gem from xkcd. It takes a look at Saturn’s polar storm that takes the shape of a hexagon, not a circle or anything else.
Of course the inside threat are those little bodies of coronavirus causing Covid-19. We cover them a lot here. But there are also threats from little bodies outside, way outside. Like asteroids impacting us. And that was the news yesterday when NASA announced improved data from a mission to the asteroid Bennu allowed it to refine its orbital model.
And we have reason to ever just so very slightly worry. Because there is a very slight chance that Bennu will impact Earth. In 2182. The New York Timesarticle where I read the news included a motion graphic produced by NASA to explain that the determining factor will be a near pass in 2135.
Essentially, the exact course Bennu takes as it passes Earth in 2135 will determine its path in 2182. But just a few slight variations could send it colliding into Earth. Though, to be clear, it’s only a 1-in-1750 chance.
NASA used the metaphor of keyholes to explain the concept. The potential orbits in 2135 function as keyholes and should Bennu pass into the right keyhole, it will setup a collision with Earth in 2182. Hence the use of little keyholes in the motion graphic that accompanied the article.
But who knows, if we’re lucky the United Federation of Planets will still be formed in 2161 and the starship Enterprise will gently nudge Bennu back into a non-threatening orbit.
Yesterday I mentioned more about revolutions, well today we’re talking about Mars, a planet that revolves around the Sun. Late last week scientists working with the InSight lander on the Red Planet published their findings. Turns out we need to rethink what we know about Mars.
First, the planet is probably much older than Earth. Mars’ composition also differs from Earth in some significant ways. InSight mapped the interior of Mars by studying the seismic waves (think like sound waves but through the inside of planets) of marsquakes.
The Wall Street Journal published a great article spelling out the findings in detail that is well worth the read. It also included some nice graphics helping to support the piece. The one I wanted to highlight, however, was a brilliant comparison of Mars to Earth.
Conceptually this is important, because many diagrams and graphics I’ve seen about these findings only detail the interior of Mars. But what makes Mars important is how it differs from Earth, and let’s be honest, how many of us remember our Earth science classes at school and can diagram out the interior of Earth?
And right here the designer compares the smaller—and now older—brother of Earth. Again, read the article for the details, but in short, some of the key findings are that the core is larger, but also lighter, than we thought. Our planet’s core differs because Earth has two parts: a solid and heavy ball of iron and nickel surrounded by a liquid core that spins. That spinning core creates the magnetic fields that protect our planet from the Sun and have kept our atmosphere intact. Mars doesn’t have that. And that’s in part because, given the core is larger than we thought, the mantle is smaller.
A smaller mantle means that certain materials couldn’t form that insulate the Earth’s core. So while Earth’s core has been prevented from cooling and slowing down, Mars was not. And so while it did have a magnetic field at one point, that slowing, cooling core slowly dissipated the magnetic field. That may be why the planet, once rich in water, now is a barren rock exposed to the Sun.
Again, this is a big deal in terms of planetary science. Consider that Earth and Mars are broadly made of the same materials that orbited the Sun billions of years ago. But Mars took those same ingredients and made itself into a very different planet. And now we know quite a good deal more about the Red Planet.
One last point to make about the graphic above. Again, many illustrations will increase the size of the crust to make it more visible. Here the designer chose to keep it more in proportion to the scale of the planets’ interiors. (Even though Mars’ crust is quite a bit thicker than Earth’s.) I think that’s important because it puts us into perspective. We can build monuments like the Pyramids that last thousands of years and dig bore holes miles deep and tunnel out connections through mountain ranges, but that also just scratches the surface of the crust. But that crust is the thinnest of shells over the mantle and cores of these planets.
That life began and took hold on Earth, on that thinnest of shells protected by a magnetic field because of a spinning molten core buried at the centre of the planet…something to think about sometimes.
Last week we ended the week with a Friday post looking at Covid-19 cases. And they are not trending in the right direction, to put it mildly. Now I’m not sure I like the Covid post being on Friday, but it also doesn’t make sense on Mondays any longer given the lack of data updates from Virginia and Illinois at the weekend.
I figured this week we could at least begin with a lighthearted post to balance out last week’s ending. And we have a great piece from Indexed that tackles two of my favourite subjects, astronomy and history. She titled the piece brilliantly, “Regarding both astrophysics and and the popularity of guillotines”.
And hopefully later this week I will address one of those two topics a little more in depth. But for now, begin your week with mirth because I will update you all with the new Covid data later this week. Spoiler: it’s not getting any better.
If you didn’t hear the news, scientists have discovered a compound in the atmosphere of Venus. They’ve also ruled out a number of the normal ways the compound is created, and we’re left with two possibilities: some kind of unknown chemistry/chemical process or…aliens.
It’s got to be aliens. Because it’s Friday.
And because it’s Friday, we can turn to xkcd, who covered this news brilliantly.
It’s Friday, everyone, and we’ve made it to the end of the week. And with the successful launch of Perseverance yesterday, this post from xkcd made a lot of sense. For those that don’t enjoy astronomy, basically stars have habitable zones, or sometimes the Goldilocks zone, around the star where planets would likely be neither too hot nor too cold for liquid water to form on the surface of orbiting planets. And since life as we presently know it requires water, it makes sense that these zones are where we focus our attention in studies of exoplanets.
Yesterday in the early hours of the morning was technically the latest full moon. And so since today is Friday and we all made it to the end of the week, it seems like a good time to let xkcd educate us all on lunar periodicity.
In science news, we turn to graphics about planets and things. Specifically we are talking about exoplanets, i.e. planets that exist outside our solar system. Keep in mind that we have only been able to detect exoplanets since the 1990s. Prior to then, how rare was our system with all our planets? It could have been very rare. Now we know, probably not so much.
But, in all of that discovery, we are missing entire types of planets. This article published by Forbes does a nice job explaining why. But one of the key types of planets that we have been unable to discover heretofore have been: intermediately distant, giant planets. Think the Jupiters and Saturns of our system. Prior to now we could detect massive Jupiter-like planets orbiting super near to their distant stars. Or, we could detect super massive planets orbiting very far away. The in-betweeners? Not so much.
The above screenshot does a good job of showing where new detection methods have allowed scientists to begin to fill in the gaps. It shows how there is an enormous gap between what we have discovered and how they have been discovered. And the article does a nice job explaining how the science works in that only now with our longer periods of observation will help resolve certain issues.
From a design standpoint, this isn’t a super complicated graphic. It does rely upon a logarithmic scale, which isn’t common in non-scientific or academic papers. But this graphic comes from that environment, so it makes a lot of sense. The article is full of graphics from third-party sources, but I found this the most informative because of that very gap it highlights and how the new work (the stars) begin to fill it in.
Credit for the screenshotted piece goes to E. L. Rickman et al.