Activity for J.D. Ray
| Type | On... | Excerpt | Status | Date |
|---|---|---|---|---|
| Question | — |
Would a water-bearing, Earth-sized moon orbiting a gas giant have tides? I ran across this article today about how moons might have moons. In Daniel Keys Moran's universe, an Earth-sized planet named November orbits a gas giant named Prometheus. November is inhabited, colonized by humans. ... The next time humans will make an attempt similar to this one is in the mi... (more) |
— | over 5 years ago |
| Question | — |
Chemical propulsion for first stage of a light sail deployment? A Russian billionaire wants to send postage stamp-sized probes off to Alpha Centauri using meter-square light sails. Regardless of the practicality of such an attempt, is there a lot to be gained by using a small chemical rocket to boost a deployment mechanism out of LEO up to some speed before depl... (more) |
— | about 8 years ago |
| Question | — |
Will moons orbiting gas giants always be tidally locked? Inspired by this article about the Kepler-enabled search for life-supporting moons, I came over here to learn more about the concept. I found this very complicated answer to a very complicated question on the subject, part of which says: Tidal locking will occur at some point in time. You can't ... (more) |
— | about 8 years ago |
| Question | — |
Metal foam for stopping meteorites? I just spotted this article about a metal foam that stops armor-piercing bullets as well as radiation. It's a press article, not a scholarly paper, so it may be complete bunk. And rifle bullets are amazingly slow relative to just about any object wandering around in orbit. However, metal foam seem... (more) |
— | about 8 years ago |
| Question | — |
61 Virginis Mission Design: Solar System-sized Rail Gun for Ship Acceleration? In this answer to another question, solar system-scale rail gun acceleration (and deceleration) was brought up as an alternative, and I found this intriguing. It's worth another question at least. Basic Idea In a mass accelerator (rail gun), an object is drawn through a ring using an electromagnet... (more) |
— | about 8 years ago |
| Question | — |
61 Virginis Mission Design: Long Term High Gee Acceleration and the Human Body I'm designing a mission to a planet orbiting 61 Virginis (27.9 ly distant), and want to stay within physics that we're aware of (e.g. no warp drive). I've asked questions here and here, and the answers to those tell me that it's a tall order. For one, getting up to a reasonable fraction of the spee... (more) |
— | about 8 years ago |
| Question | — |
61 Virginis Mission Design: Ship Mass I'm continuing questions rooted in the same idea: a manned mission to a planet around 61 Virginis. The first set of related questions was asked here. We're sending a crew of twelve. They'll be in mild stasis for most of the mission, though will have to wake up and move around in a gravity environm... (more) |
— | about 8 years ago |
| Question | — |
Laser-boosted Solar Sails to 61 Virginis? I've just read this article and watched the accompanying video. Heady stuff, for sure. I'm particularly intrigued by the concept of a "solar gravitational lens telescope" somewhere out near the heliopause. I'm surprised this isn't bigger news. I don't know how to effectively read the charts, nor ... (more) |
— | about 8 years ago |
| Question | — |
What happens when one planet "lands" on another? Imagine, if you will, an Earth-like planet orbiting a Sol-like star. Now imagine that, from somewhere outside the solar system, a rogue planet, rocky and of roughly the same size and mass of the first planet, enters the solar system on a trajectory that eventually takes it so close to the first plan... (more) |
— | about 8 years ago |