'Sun-Like' Stars | Hacker News Reader

'Sun-Like' Stars

centauri-dreams.org

64 pointsJPLeRouzic20 comments

We used to log “Sun-likes” with a garage telescope, a Commodore 64, and a lot of guesswork. If it looked yellow and didn’t blink, it made the list. Half of them were porch lights, but we stood by our catalog.

One of the comments on that page mentions that we see the G-class stars like the Sun as "yellowish", but in fact they are white, like a LED lamp with a color temperature of 5500 K or 6000 K.

The reason for this is not mentioned there, which is that the atmosphere of the Earth acts like a low-pass filter for the direct light that comes from the Sun or from a star, converting the white light into yellowish light. The missing bluish light is diffused over the sky, giving it its blue color. The night sky is also blue, but at a many times lower luminance, so that it seems black.

On the Moon, the Sun will appear as perfectly white, on a perfectly black sky.

We accounted for that by calibrating against a halogen desk lamp and my uncle’s welding arc. Anything in between was classified as “solar-adjacent.” Worked fine unless the neighbor lit his barbecue.

lol, sounds like a reddit bot commenting with max snark ;)

Bot? I’ve been manually backing up my emails to cassette since ’98. If I was a bot, my tapes wouldn’t squeal during thunderstorms.

From the article:

> A confused public is less likely to support studies in areas it does not understand.

What a great point to remember

Any idea who this Paul Gilster is? Or Tau Zero? He says he was trained as a medievalist who later turned into flight instructor and now he's obviously fascinated with astronomy and exoplanets.

I'm always wary of sites like this, but this one seems to have a long history, starting in 2004, and as far as I can tell the articles are solid (or at least, not quackery). This article in particular seems reasonable, too.

Apparently Tau Zero was created after a government program to investigate interstellar travel propulsion methods concluded, and the program manager wanted to keep it going, and it's a group of people who want to visit other stars:

https://en.wikipedia.org/wiki/Breakthrough_Propulsion_Physic...

> it's a group of people who want to visit other stars

And I want a pet unicorn. And a male contraceptive pill.

Only one of those things is ever going to happen.

> I'm always wary of sites like this

I can't really think of much that is more legit than a special purpose blog distilling current research papers into long form blog posts, except perhaps the research papers themselves?

For every site doing that, there are 10 sites pretending to do that, with various levels of quackery.

It makes sense to be wary at first.

I feel like quackery and clickbait give strong vibes which can be detected immediately. This has the feel of an educated and deeply interested hobbyist or some astronomer's side project.

Agreed that it has the right vibes.

But it always pay to be a little wary, which is why I made my comment.

> I can't really think of much that is more legit than a special purpose blog distilling current research papers into long form blog posts, except perhaps the research papers themselves?

If that's what they are doing. But it's hard to tell without looking carefully and sifting through more than a couple of articles.

Like I said, it seems legit.

As long as they stay that way.

Tau Zero is the title of an SF book by Poul Anderson in which humans make an STL interstellar voyage. They probably got inspired from that book.