The REAL Possibility of Mapping Alien Planets!
Why Hacker News recommends it
It is the go-to explanation whenever a thread touches on imaging exoplanets or solar gravitational lens telescopes.
What it is
PBS Space Time explains the proposal to use the Sun's gravity as a giant lens, sending a train of small light-sail spacecraft to the focal point roughly 550 AU out. It covers how such a telescope could image exoplanets in surprising detail and the engineering challenges involved.
Recommended by 4 HN commenters across 6 different months, 2023 to 2024.
What Hacker News said
Strong rec lasc4r · 2023-06 · on “Monster gravitational waves spotted for first time”
I feel like you need to see _this_ spacetime video: [this video] If you think LISA is mad this will blow your mind.
Recommends nkrisc · 2023-01 · on “Wolf 1069B: Earth-mass planet in the habitable zone of a nearby, low-mass star”
Pretty good explanation of the technique and challenges involved: [this video] One figure that stands out, the probe would need to be about 550 AU from the sun. Voyager 1 is about 150 AU away from the sun right now, for comparison.
Recommends Galaxeblaffer · 2023-03 · on “JWST gets best view yet of planet in hotly pursued star system”
good old Space Time has a pretty good video on this [this video] and it might even be possible and more feasible to use planets [LINK] and even earth [LINK] as lenses
Recommends tzs · 2024-01 · on “Rumors Circulating That James Webb Has Discovered Life on Another World”
That's one approach to use the sun as a gravitational lens for looking at exoplanets. There's another approach that instead of one big telescope sends a series of much smaller telescopes, small enough that light sails would be effective for getting them to where they need to go. Here's a PBS Space Time episode [1] that talks about this general topic, and then about the series of smaller telescopes approach. [1] [this video]
Recommends tzs · 2024-02 · on “Are we visible to advanced alien civilizations?”
Yes, it is possible. Briefly, you use your solar system's star as a gravitational lens. There are currently a couple proposals working their way through the system to do that here in our solar system. It doesn't require technology much beyond what we already have, nor is it much more expensive than other unmanned deep space missions. We wouldn't be able to see pyramid sized objects on alien planets that way because the Sun is only about 1.4 million km diameter, and from other comments it would take a few million km. But for aliens with a bigger star? No problem. Here's a PBS Space Time episode that talks about the proposals for building a Sun based gravity lens telescope [1]. [1] [this video]
Recommends tzs · 2024-10 · on “A solar gravitational lens will be humanity's most powerful telescope (2022)”
Here's a PBS Space Time episode [1] from a couple years ago that describes a couple different proposals for how to do this that take quite different approaches. It starts getting into the specifics of those approaches at 7 minutes in if you don't need the introductory material. [1] [this video]
Cites hackerlight · 2024-01 · on “Are we stuck with the Zoo Hypothesis?”
Right, human technology can detect up to hundreds of light years[1], but presumably advanced alien technology can go further. See for example[2]. Hard to say how far. [1] [LINK] [2] [this video]