Comments by "H. de Jong" (@h.dejong2531) on "NASA Finally Shows What's Inside Jupiter's Great Red Spot" video.

NASA has published photos. Thank the clown who made this video for not using them.
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Depends. The Voyagers got to Jupiter much quicker, but a high approach speed makes it difficult to insert a spacecraft into orbit: you have to slow down by a lot, which takes a lot of fuel, which makes the mission more expensive to launch (not so much the fuel cost, but you need a bigger launcher to get all that fuel to Jupiter). So Juno was launched at a lower speed so they wouldn't have to brake as much on arrival.
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@TheHaughtyOsprey You claim there is no 'clear footage of a rocket launch'. I provided a magnificent example and disproved your claim.
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NASA has done this occasionally going as far back as the Voyagers: there's a brief video of Jupiter, taken at 1 frame per 90 seconds while the spacecraft approaches Jupiter. https://www.youtube.com/watch?v=BsQLy1ft8M4 Video is not done often because video files are very large and the amount of data they can send across such large distances is limited: 1.5 Mb/hour for Juno. So most videos you see will be timelapse rather than 24 fps. The closer to Earth, the easier this gets: Mars rover Perseverance has sent us video of Ingenuity flights, for instance.
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@natturner2681 There is a lot of evidence that we have landed on the Moon. There is no evidence that we didn't. Just a lot of half-baked arguments that are easily debunked by anyone who has studied physics.
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NASA has published plenty of images of the Red Spot. Blame the maker of this video for not including any.
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@thinkoutsidethelines8265 Juno is limited to about 1.5 Mb/hour of downlink. It has a bunch of scientific instruments that have to share that downlink, so most of the time they'll choose to create a photo instead of taking a video (=24 photos per second). .
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The same way we often deal with radiation here on Earth: don't spend too much time being exposed to it. The Apollo spacecraft spent about 1 hour in the van Allen belts, giving the astronauts a radiation dose of about 2 Rad. A dose of 300 Rad in 1 hour is lethal. For Orion, we need something better. Not because of the Van Allen belts, but because of the journey to Mars which takes several months. So NASA is looking at shielding materials, and powerful electromagnets that can create a local magnetosphere. For unmanned spacecraft, Earth's van Allen belts are not a big deal either. Jupiter has van Allen belts too, the radiation levels there are much higher. So Juno's electronics are in a shielded box, and Juno's orbit is designed to minimize the time it spends in Jupiter's van Allen belts.
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Clear footage of a rocket launch: https://www.youtube.com/watch?v=W2VygftZSCs
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@TheHaughtyOsprey Rocket launches are pretty straightforward. Clear the launch tower, then a pitch maneuver as the rocket starts to accelerate to orbital speed.
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@TheHaughtyOsprey The atmosphere rotates along with the ground. Just like a liquid in a sphere (or other container): when you start to spin the container, the liquid 'stays behind' a bit (due to inertia), but after a while, the liquid will have the same speed as the container.
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@TheHaughtyOsprey When it's in orbit, a satellite moves parallel to the Earth's surface. To get to orbit, you need 2 things: 1. enough altitude to be above the atmosphere - at least 200 km. 2. enough horizontal speed - about 8 km/s. So you launch vertically (because that's the easiest way to place a rocket on the launch pad). Then after launch, you soon start a pitch maneuver that will allow you to start building that horizontal speed while still building altitude.
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@TheHaughtyOsprey Gravity always points to the center of the Earth, including the poles. So at the pole like everywhere else, when you fire a bullet it's pulled toward the ground: it follows a parabolic trajectory. The moon is visible from a hemisphere: the half of the Earth that's closer to the moon. On the edge of that hemisphere, you see the Moon just above the horizon, in the middle of the hemisphere the Moon will be right overhead. You can visualize this: take a ball (or other spherical object), and place it in front of a lamp, a few feet away. Switch other lights in the room off. One half of the sphere will be illuminated - everyone living on this half can see the light. The other half of the sphere is dark - people living on this half can't see the light.
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@TheHaughtyOsprey it's easy to build a model and make some claims about it. The concept of gravity has been tested thousands of times and the only problem we've found is in the behavior of galaxies (which led to the idea of dark matter and the search for what that can be). At all other scales the predictions made by the theory of gravity are spot-on. If you look at falling objects on Earth, you have to take into account gravity and air resistance. This goes for many theories and models: you have to look at all factors.
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@TheHaughtyOsprey At the poles, the centrifugal force from rotation is at its lowest. It's highest at the equator: if you spin a sphere at 1 revolution per minute, the equator of that sphere has a speed of π x the diameter of the sphere, near the poles the speed is π x the local diameter which is a lot smaller. Even at the equator, centrifugal force provides an acceleration of only 0.03 m/s^2, compared to gravity's acceleration of 9.81 m/s^2. If you weigh yourself on the pole and at the equator, you'll see this difference in the measured weight.
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@TheHaughtyOsprey What kind of experiments do you want to do? I live in Europe...
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@TheHaughtyOsprey But can that same model replace gravity in other places? Humans are affected by gravity (=our weight). Even the strongest electromagnetic fields we can create don't affect our weight. I had an MRI scan a few years ago. I was not allowed to bring anything made of metal into the room, because it would be ripped from my hand and fly into the MRI machine at high speed. I could walk normally in and out of the room. If the force that pulls us down toward the ground is electromagnetic, the MRI machine would have affected me.
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We study Jupiter and other planets to learn more about our solar system: how did it form, how does it work now. We get to see what's possible when conditions are very different from Earth. We explore because we can. And sometimes we are surprised by our discoveries: we found moons around Jupiter and Saturns that have liquid water oceans underneath an ice crust. We might find life there.
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@natturner2681 This is basic physics. Kinetic energy goes up with the square of the speed. To get a spacecraft flying at Voyager's speed into orbit around Jupiter, you'd need a rocket that weighs several hundred tons. So instead of launching 800 kg on its way to Jupiter, you'd have to launch 1000 times more. We have no rockets powerful enough to do that.
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@natturner2681 It's a lot easier to land on the Moon (needs 1.5 km/s of delta-V) than to get into Jupiter orbit when you approach at 10 km/s. The amount of fuel needed is exponential. The Moon's low gravity really works in our favor.
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@natturner2681 We did land on the Moon already. There's no 'limit' we can't go beyond.
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There's nothing wrong with our technology. The maker of this video was too lazy to find the actual images.
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Because gravity pulls them into the most compact shape possible - which is a sphere.
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