Wonder if there is a immediate reason they're practicing this.
Astronomy & Space Exploration
- Thread starter MrMarcello
- Start date
There isn't, but it is statistically certain that such a reason will be detected at some point in the future.
The people on the astronomy podcast I listen to (Walkabout the Galaxy) have been a bit perplexed at what exactly they're going to figure out with DART. To hear them tell it, the physics are pretty much already determined, so if you know what kind of surface you're hitting (solid or not) you can perfectly predict the result. Maybe this is just a case of putting theories to the test, just to be absolutely sure.
Lots of theories have been disproven in space, or more accurately turned out to be based on wrong assumptions. Happened all the time at Redstone and in the early days of NASA.
Sure, but aren't we talking pretty basic physics here? You hit something of a known mass going a known speed at a known distance to the Earth (or rather a distance from where the Earth is going to be), with something of a known mass at a known speed. It will impart a known amount of energy, which is going to affect the trajectory in a predictable way... seemingly. That's the argument they've been making, anyway, though they've still been following it with interest.
That's exactly what I've been thinking as well. It's collisions from classical mechanics.
Yeah but actually being able to hit it is not so easy. A lot of the demonstration was focused on the target acquisition system and how to hit an object travelling at enormous speeds. We still struggle to reliably hit ballistic missiles, let alone something many magnitudes faster and further away.
You also have to hit the right bit. We might know the mass of an asteroid but we don't know the internal structure of it, some parts may have low density or some other property that makes it a bad place to strike.
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Probably the one we crashed into, after knocking it onto a course for us.
That and presumably when you hit it you eject stuff into space. How that fractures, what it is and all that jazz presumably affects your classical mechanics - it's not just 2 snooker balls bouncing off each other.
I did get the feeling it was a relatively cheap mission with some scientific value, not a lot that could go wrong and a lot of expected publicity value for NASA. For example...
"We showed the world that NASA is serious as a defender of this planet," Bill Nelson, NASA's administrator, said in a briefing on Tuesday. "This is a watershed moment for planetary defense and all of humanity."
Beautiful...
Very cool. The proto planet was called Theia and was on a similar orbit until it collided with earth.
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If one day they announced there was a giant meteor heading for earth. And they said don't worry were sending a craft to collide with it charging its trajectory and saving life on earth. But that they'd never tried it before..
If I'm going to be nitpicky (and I am; it's in my contract), this didn't tell us anything at all about changing the trajectory of a giant meteor since it was an asteroid. But I'm sticking to my general point, that this wasn't anything groundbreaking. It's neat, sure, and it's very cool that we managed to actually hit it, but I really doubt we learned a lot from it.
Edit: I see it more as a proof of concept. NASA sort of going "look what we're capable of".
Wonder if this is the only Moon in the Solar System which formed in this way.
As you say not ground breaking. But nonetheless it was a worthwhile experiment, mainly as a proof of concept.
Yeah, definitely worth doing.
We don't know for sure. But there are suggestions that satellites like Phobos, Deimos, Charon et cetera were formed through similar-ish impactor processes. Interestingly, Phobos is also expected to collide with Mars in roughly 50 million years (or get fragmented into a ring system once it reaches the Roche limit).
New Mars Model Details the Violent Birth of Phobos and Deimos
It perhads wasn't meant to be a scientific learning excersize from the outset. But more of a practise excersize in the event the killer asteroid comes our way..
Brilliant question that Mars vid looks a must watch
50m from now
Speaking of things that are happening in a surprisingly short time, the rings of Saturn might very well be completely gone in a hundred million years. They might also be less than a hundred million years old, so this extremely characteristic feature might be actually be just a blip in the life of the planet.
Ok. Thanks for that.
That picture is stunning.
In 4K
Not gonna lie, I was hoping Webb would do a lot more than just clearer images of what we’ve already seen from Hubble.
I’m sure it will, but I want it now dammit.
I’m sure it will, but I want it now dammit.
Looks like a chicken or duck head in the bottom right.
Nimic breaking the page again.
OK, not this time, but figured it was time to remind you anyway.
In case anyone else has the question...
"Why do all the stars have 8 points in the James Webb images? An astronomer explains"
"Why do all the stars have 8 points in the James Webb images? An astronomer explains"
A real life, calibration test maybe? Books are perfects, engineering is not.
Pretty much this. DART was pretty useless as a scientific mission, but one should essentially see it as a first test firing of our planetary defense.
What if it wasn't a practice?
It was. The orbit of the target was well known and it was and still is harmless.
If it wasn't, we really messed up the targeting. It's really interesting, actually. They knew that it would be a lot more difficult to change the orbit of a large asteroid, not to mention more difficult to spot the change, so they hit the "moon" of an asteroid instead and then measured the change in its orbit around the main asteroid. It was still 160-170 meters in diameter, so not tiny.
Two massive halos of dark matter merging together...?
https://www.esa.int/Science_Explora...overs_dense_cosmic_knot_in_the_early_Universe
" The three confirmed galaxies are orbiting each other at incredibly high speeds, an indication that a great deal of mass is present. When combined with how closely they are packed into the region around this quasar, the team believes this marks one of the densest known areas of galaxy formation in the early Universe. “Even a dense knot of dark matter isn’t sufficient to explain it,” Wylezalek says. “We think we could be seeing a region where two massive halos of dark matter are merging together.” "
https://www.esa.int/Science_Explora...overs_dense_cosmic_knot_in_the_early_Universe
" The three confirmed galaxies are orbiting each other at incredibly high speeds, an indication that a great deal of mass is present. When combined with how closely they are packed into the region around this quasar, the team believes this marks one of the densest known areas of galaxy formation in the early Universe. “Even a dense knot of dark matter isn’t sufficient to explain it,” Wylezalek says. “We think we could be seeing a region where two massive halos of dark matter are merging together.” "
Cool! One of the most interesting things about galaxies is that most of their gravity isn't from matter, but from a dark matter halo which is probably responsible for bringing the galaxy together in the first place. And it even extends beyond the galaxy.
The Universe is wild.
It boggles my mind how we are conscious of our existence and capable of querying the Universe, only to find out how unfathomably complex it is. If we don't understand the largest scale (dark matter), the smallest scale (quantum) or the individual scale (our brain/mind), what do we actually understand?
"There is a theory which states that if ever anyone discovers exactly what the Universe is for and why it is here, it will instantly disappear and be replaced by something even more bizarre and inexplicable. There is another theory which states that this has already happened." (Douglas Adams)
I wonder if it happens in real-time, as each layer is understood another appears...