Activity for Jarred Allen‭

Type	On...	Excerpt	Status	Date
Question	—	How would people conceivably escape a planet too large for chemical rockets? I was reading this article from NASA about chemical rockets and they argue that, with a planet 50% larger than the Earth (assuming similar density, about 1.5G surface gravity), it would be impossible for chemical rockets to escape. Note that I don't care specifically about those exact values, just as... (more)	—	about 6 years ago
Question	—	How can I have a habitable world on which life can not develop? For my story, I need there to be a planet close to the home world of my species (in the same star system) that the species could easily get to and easily colonize, but that does not have its own life already on it. Assume that this species is very similar to humans. I figured that the easiest way t... (more)	—	about 7 years ago
Question	—	What would make scientists realize that they are on a toroidal world? In my story, a portal is opened from the Earth to an alternate world. However, this world is toroidal in shape and has a surface gravity equal to that of Earth. It rotates around an axis that goes through the center of the circle perpendicular to all major radii, and its day/night cycle (assuming tha... (more)	—	over 7 years ago
Question	—	How would gravity work in this alternate universe? In my universe, gravity varies with the inverse of the distance (instead of the inverse square of the distance). I already know that this means that all circular orbits around the same object will have the same speed, and no true escape trajectories can exist, but there are some facts that I can't fi... (more)	—	over 7 years ago
Question	—	Effects of an Asteroid Aerocapture on Earth? As a follow-up to this question: Could an asteroid aerocapture around Earth? The answers seem to indicate that it would be possible for such a thing to happen (an asteroid aerocapturing using the Earth's atmosphere, and then getting a gravity assist from the moon to stabilize the orbit), even though... (more)	—	almost 8 years ago
Question	—	Could an asteroid aerocapture around Earth? Would it be possible for an asteroid in solar orbit to go near enough to the Earth that the Earth's atmosphere slows it down into an orbit that is, aside from its low perigee, stable without using a third object (such as the moon) to slow down? Or would the necessary forces destroy the asteroid? If ... (more)	—	almost 8 years ago
Question	—	Natural Kessler Syndrome Is there a way that, on an Earth-like planet (similar size, mass, composition, resources, moon, climate, star orbit, etc.) some natural process could create and continually renew a Kessler Syndrome that would render any mission to low earth orbit (or higher) impossible, and for it to replenish itself... (more)	—	almost 8 years ago
Question	—	Ecosystem that never touches ground Would it be possible for a planet to have an ecosystem where life lives without ever touching the ground? By this, I mean that the producers (whether by photosynthesis, chemosynthesis, or other methods) float (or fly, etc.) above the ground, with the consumers also doing this, with none of those ever... (more)	—	almost 8 years ago