Comments by "H. de Jong" (@h.dejong2531) on "The Final Images We Will Ever See of Pluto and Arrokoth" video.

  1. That's not a viable concept. A relay halfway between us and Pluto would orbit the Sun, so the relay would be out of place most of the time. It's much easier and cheaper just to build a larger antenna on Earth. The next step is probably laser communications, which would require a receiver satellite in Earth orbit.
    2
  2. That depends on the size of the planet. Everything with a diameter of about 1000 km and up has enough gravity that it pulls itself into a sphere. Anything smaller has random shapes.
    2
  3. Yes, the thrusters were used for attitude control. It's the best method we have for really long missions. We can use electricity (to power reaction wheels), but reaction wheels tend to wear out. Hydrazine is a monopropellant: pass it over a catalyst, and it decomposes, creating lots of hot gas.
    2
  4. Natural satellites of other planets are generally called moons.
    2
  5.  @1legend517  I should have explained. For telescopes, it's useful to specify the resolution as an angle. The angle remains the same for all distances, but if you said "the resolution is 1 meter/pixel" that's only valid for one distance.  The smaller the angle, the better the resolution. 1 arcsecond is 1/3600 of 1 degree. Let's look at the Moon. That is about 0.5 degrees, or 1800 arcseconds wide. So Hubble can see details that are 1800/50 or 1/36 the diameter of the moon. That's about 95 km per pixel. JWST can see details 1800/31, that's 1/58 the diameter of the moon, or 58 km per pixel.
    2
  6. Yes. It wasn't possible at all in 2006. The New Horizons team has been thinking about an orbiter: "The mission ... put a New Horizons-scale spacecraft with new instruments into Pluto orbit. It requires one of the massive new, Saturn V-class launch vehicles now in development, a Jupiter gravity assist, and a nuclear electric stage augmented by a chemical propulsion braking stage to reach Pluto orbit."
    2
  7. Cell service (and wifi) is short-range radio, with a tiny antenna and a $3 receiver in your phone. These systems are built deliberately to have short range, because the shorter the range, the more cell towers you can install without them interfering with each other, and the more users you can serve. Radio waves don't travel well through solid obstacles, so each wall between you and the cell tower reduces your signal. NASA uses a giant dish to receive signals from New Horizons, builds the best receiver electronics money can buy ($100 million each, the receiver is cooled to cryogenic temperatures to reduce noise), and they have a clear line of sight without obstacles between transmitter and receiver. At these distances, communication is slow: NH sends data at 1000 bits/s. See, when you investigate instead of going straight to "I can't believe", you might learn something.
    2
  8. pretty good. The gaps between objects are hundreds of millions of km.
    2
  9. He does a pretty good job of labeling enhanced images. 3:54 is an unmodified image.
    2
  10. Voyager 1 is headed North out of the ecliptic plane, Voyager 2 is headed South, and New Horizons is staying in the ecliptic plane. Their trajectories were dictated by the positions of the planets they visited.
    2
  11. No, it's too small for that.
    1
  12. Ultima Thule was a preliminary choice by the team. When that was published, it turned out that name is tainted by the Nazis, so they chose a different name.
    1
  13. You're assuming something that isn't true.
    1
  14. Yes.
    1
  15. Yes.
    1
  16. Ultima Thule was a preliminary choice by the team. When that was published, it turned out that name is tainted by the Nazis, so they chose a different name.
    1
  17. You got so close, and then instead of finishing the calculation you gave up and succumbed to nonsense. You forgot about the gain of the antenna on New Horizons, and the gain of the receiving antenna on Earth, and the sensitivity of the receiver. This receiver can detect signals as low as -170 dBm. The data rate is only 1 kbit/s, so it took 18 months do download all the data of the Pluto encounter.
    1
  18. Ultima Thule was a preliminary choice by the team. When that was published, it turned out that name is tainted by the Nazis, so they chose a different name.
    1
  19.  @1legend517  No, JWST's resolution is similar to Hubble's.
    1
  20.  @1legend517  Hubble has a resolution of 50 milliarcseconds/pixel. JWST is 31 mas/px at its shortest wavelengths.
    1
  21. 1. Galaxies are very large compared to Pluto. A galaxy one billion lightyears away takes up a larger patch of sky than Pluto. 2. Stars are only visible because they're very bright: they're smaller than a single pixel.
    1
  22. Because that would have required a much larger spacecraft, to carry enough fuel to brake. We didn't have a large-enough rocket for such a mission.
    1
  23. The light level on Pluto is comparable to dusk on Earth. With long exposures, you can get excellent photos.
    1
  24. on hte order of femtowatts.
    1
  25.  @lunamaria1048  Edgeworth and Kuiper theorized that there would be a large number of small objects outside of Neptune's orbit. They also thought some of those might become short-period comet. We found thousands of small objects, confirming that part of their hypothesis. Since then we've gathered more data about comets, and found that the short-period comets originate from the scattered disk instead. That's actual science, not religion.
    1
  26. the name 'Ultima Thule' has been coopted by the Nazis.
    1
  27. 0:15 shows what Hubble sees of Pluto. The only way to improve that is by using a larger telescope. Composite images can be made via interferometry; unfortunately it's difficult to do that for visible light.
    1
  28. Galaxies are very large compared to Pluto. A galaxy one billion lightyears away takes up a larger patch of sky than Pluto.
    1
  29. That's not what the change in definition was about though. Nobody's saying dwarf planets are dead rocks.
    1
  30. JWST continues to operate normally.
    1
  31. Rockets travel at a few km/s. Light and radio waves travel at 300,000 km/s. Can you see the difference?
    1
  32. Yes, they are moons.
    1
  33. The used long exposure times to get well-lit images.
    1
  34. Stellardrone.
    1
  35. Incorrect.
    1