You might find it hard to imagine gravity as a weak force, but consider that a small magnet can hold up a paper clip, even though the entire earth is pulling down on it.
Read this from chels (my comments are below):
Because we don’t all have the education or knowledge to be able to imagine ourselves in space the way a cinematic masterpiece can place us there. It’s not that mysterious, you pretentious windbag.
I have so many problems with Neil deGrasse Tyson’s approach to science communication, and usually I just pass it off as “eh, this guy ain’t for me,” but this tweet really makes me angry. Sometimes he knows how to spin a soundbite, but more often than not, he comes off as condescending and pedantic. So why do we enjoy this “make-believe space” more than the reality of manned space missions?
How about this: how about the notion that film has the capability to show us realities outside our own, to take us places most people will never go.
How about the fact that our government and our public education system place little emphasis on the importance of science and the endeavor of spaceflight, making it hard for people to really understand what it takes to put humans on the International Space Station.
How about the idea that a filmmaker can say more in 90 minutes than NASA can say in 10 years of press releases.
Or how about this: art is the lens through which science transforms into wonder. We can do all the most amazing science in the world, but if we don’t have eloquent, engaging, inclusive science communicators (even if they happen to be film directors in disguise) then the work will remain a mystery to the public.
I’ve heard there are scientific inaccuracies in this movie, and I hardly care. If the most talked about movie of the season is one that centers on astronauts, a spacewalk, and satellites, I’d say we’re on the right track. I’m seeing the film on Tuesday and I can’t wait to be wowed.
(See also: the best response to this tweet)
In general, I like NdT a lot. Certainly more than Chelsea does. But I have to agree with her here. I’m pretty sure that Neil was really just trying to fire up support for our manned space program in a time of epic governmental nincompoopery, this is kind of a clumsy way to do it, and he sounds like a bit of an ass.
Someone’s love for a sci-fi movie that is set in space does not preclude them from also loving actual people in space, and Chels lays out some excellent reasons (I particularly like the “art is the lens through science…” part). Especially when the director of that movie goes to such great lengths to get things scientifically right. Plus there’s that response tweet at the bottom, which is the sickest burn.
There’s also the fact that NdT is just plain wrong. Gravity set a record for October movies with a $55.6 million opening weekend haul. With an average national ticket price approaching $9, this means that a hair under 6.2 million people went to see Gravity this weekend. That’s way more people than would ever watch real people in space right?
Wrong. To date, more than 9.1 million people have watched Chris Hadfield wring out a washcloth from the ISS. And that’s just one video. I’m not an astrophysicist, only a humble biologist, but I am pretty sure that 9 million is more than 6 million.
I’ll forgive NdT for this, because I sense that his heart was in the right place, but loving Gravity does not a space-hater make. To me, the fact that this movie exists at all is proof of how many people are looking up.
If you want another way to fire up support for our space program, maybe this is a good time for me to plug my YouTube video about that?
Great reminder that you can find amazing moments of “A-ha-ness” in everyday places. Like when your legs buckle on an elevator.
When Einstein looked at those little gravity jolts, he saw into the very heart of the cosmos. They were the key to his “ah-ha” moment. He realized that gravity isn’t about forces, it’s about falling.
Gravity, Einstein saw, is what happens when you take away forces and let things go with the flow — the flow of space. Cut the cables on your elevator and what happens (other than a lot of yelling and panic)? Inside, everything appears to go weightless. During the fall you’d float like an astronaut in a space capsule.
That was how Einstein realized that apples don’t fall because of forces; they fall because that is what space wants them to do. Gravity is space bending and stretching like taffy. Even though you can never touch space you can see it has a shape just by watching how things fall.
Misconceptions About Falling Objects
We know from physics that two objects dropped from the same height should hit the ground at exactly the same time, assuming they don’t get held back by air resistance. But do you remember exactly why that is?
Derek Muller from Veritasium helps explain how two differently-weighted balls can have completely different gravitational forces acting upon them, but still hit the ground at the same time. Now you will never forget it again, right?
Buzzing the Moon
NASA’s twin GRAIL spacecraft, Ebb and Flow, crashed into the Moon recently. Their fuel was exhausted, their mission to map lunar gravity complete. Fare thee well, fine ships. The video above is a view of their final days, skimming a mere 6 miles above the gorgeous lunar surface. I’m jealous.
"You are go for fly-by, GRAIL. The pattern is not full."
The two spacecraft orbited our rocky satellite, one lagging behind the other, sensing slight fluctuations in each other’s orbits caused by slight differences in the Moon’s gravity. For instance one passed over a spot with slightly stronger pull, it would dip ever so slightly. Communicating via microwaves, the other spacecraft would sense that dip. And so they flew, bobbing and weaving and mapping.
Technically, the Earth and the Moon aren’t perfect spheres. However, for all intents and purposes we can pretend they are, as they are certainly more perfectly round than a billiard ball. The Earth actually bulges slightly in the middle from the tug of the Moon’s gravity, like a tectonic high tide.
We know that everything with mass exerts gravity. Even the coffee cup currently next to me is pulling me toward it, and I’m pulling it toward me, however infinitesimally imperceptible that pull may be. Actually, that tug might be because I need coffee, but you get the idea. What most people don’t realize is that objects like the Earth and Moon don’t have evenly distributed mass, and likewise don’t have completely even gravity.
Everywhere on the Moon that there’s slightly denser, heavier rock, there’s slightly more gravity exerted above that spot. The GRAIL mission mapped the Moon’s blips and bulges in the greatest detail ever, giving us this abstract-art-like map:
If you want to read more about Earth’s lumpy gravity, check out this post by Phil Plait.
Can plants grow leaves up, roots down … in space?
Some new space science is helping to answer that. A plant experiment recently done on the International Space Station showed that plants do not need gravity in order to grow normal root patterns and send their leaves up toward the light. They grow more slowly, but as long as they have a light source above them, they are able to orient their direction of growth just fine (contrary to previous research).
We’ve all seen a houseplant grow toward the light, right? This is a phenomenon called positive phototropism. The microgravity experiment showed that when a plant senses light, it not only grows toward it but sends its roots the other way. The root effect is called negative phototropism, and it seems to be enough to get a normal looking plant in space.
Of course it’s not that simple, right? Nope. On Earth, it turns out that gravity does help, and plant roots have these dense little “molecular weights” that are pulled down by gravity and help a new seed orient the roots downward. They’re really cool. So it looks like, for now, that Earth plants use a combination of gravity and light to orient upleaves from downroots, and space plants can do almost as gooda job with light alone.
Bring on the space gardens! Whole Foods Lunar Base by 2020!! Would that count as organic?
(if you want to dig deep into the space plant biology, here’s the original paper)
Let’s put 2,000 ping pong balls and 30 teachers inside the vomit comet and see what happens!
Best science done with ping pong balls since these guys put 1,500 of them in a trashcan with a liquid nitrogen bomb.
NASA’s Grail Paints the Moon Abstract
It looks like some sort of modern art piece, but this actually represents the most high-resolution gravity map of the Moon ever created. Wait, scratch that. The highest resolution gravity map of anything in space, including Earth. The Earth, Moon and other celestial bodies look round, but they (and their gravity) aren’t perfectly even and spherical.
The GRAIL mission uses a pair of satellites orbiting the Moon who sense the slight bumps and blips in gravity by watching how their position relative to one another changes. We’ve looked at how that works before. The colors in the photo represent tiny fluctuations in the Moon’s gravity, just like we see on Earth.