Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Robert Carnegie Newsgroups: rec.arts.sf.written Subject: Re: OT: Surely there's an SF story with this..... Date: Sat, 31 Aug 2024 21:30:16 +0100 Organization: A noiseless patient Spider Lines: 41 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Injection-Date: Sat, 31 Aug 2024 22:30:16 +0200 (CEST) Injection-Info: dont-email.me; posting-host="8f0bee2749383225c1f9618c6190f4f2"; logging-data="1207507"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+odz8oOl0Im8lbWgi9FSGE72pQP5ImkwQ=" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:pFnTjQk5SmAqoRR3AoQDrUb97z4= In-Reply-To: Content-Language: en-GB Bytes: 2313 On 29/08/2024 19:07, Cryptoengineer wrote: > Reflect Orbital > > https://www.reflectorbital.com/lighting > > is proposing to launch a fleet of orbital mirrors to provide lighting > to nighttime locations on the Earth. > > They claim they will be able to light up a 5km diameter circle for > 4 minutes. They're accepting reservations, but I can't find any > pricing. They expect to start in Q4 2025. > > I'm *extremely* skeptical. To be even as bright as moonlight, > the mirror would have to appear 1/7 the area of the Moon in > the sky. Area? Start here: the Moon is quite dark (Pink Floyd, "It's All Dark, Really"). I take albedo 0.12 to mean that it would be 8 times brighter if painted white. Also it sheds light in all directions. And, without checking your article, I assume the mirror will be /nearer/. My bathroom mirror has an apparent size much larger than the Moon. > I can't think of a use case for 4 minutes of light, but they > also talk about using it to power up solar panel systems at > night, which makes no sense. Pop concert, one song. Or the _Romeo and Juliet_ balcony scene. Or boil an egg. > I think its either an art project, or some kind of scam to > fleece investors who are bad at math. > > Still, very stfnal. > > pt