Hacker News Reader

Comment by somenameforme | Hacker News Reader

No idea when NASA put this up [1] but it's awesome. It's the basic data on the system as well as some pretty nicely done visualizations including the ability overlay our solar system for scale. Quite interesting actually seeing what a dramatic difference the star type makes on habitable distances. This planet is way closer to its star than Mercury is the Sun, for instance. They could do with a lot more advertising for stuff like this, and not quite so much for dronecopters.

[1] - https://exoplanets.nasa.gov/exoplanet-catalog/8921/toi-715-b...

View on HN

The retro graphics here are gorgeous: https://exoplanets.nasa.gov/alien-worlds/exoplanet-travel-bu...

(Stellar, one could say.)

I think they are out of this world myself.

The guided tours are interesting. I've mentioned this before, but I am very jealous of this kind of content available for school kids. We had the slide shows with a tape recording with the unforgettable tone to signal to switch to the next slide. We had crappy VHS copies instead of the 8mm film projector, but I'm not sure it was an improvement. All of this interactive material is just so much more immersive.

Have you seen the stuff that's available in VR these days? It's not just space, too; e.g. here's a pretty engaging game that happens to explain how biological cells work: https://www.youtube.com/watch?v=Exii5RPxMH8

When Costco still did printing we printed serval of those out as posters and hung them up in the kid’s bathroom. The designs are pretty timeless and are fun to daydream about.

There was a awesome book filled to the brim with paintings of other worlds.

Cycles of fire

NASA has provided some very compelling visualizations of data over the years. One of my favorites is the meteor showers showing where the debris fields for each one are located within the solar system. You can see the original orbit of the comet that left the debris, where it currently is, when the Earth's orbit crosses the debris field, and just the overall size of the debris so that you can see why some meteor showers are "better" than others.

There's plenty of others where you can zoom in/out of the solar system to see the modeled view of the Oort cloud and get a sense of scale interactively of Sol's influence. There's also the interactive image viewers of Hubble and JWST data so we can see the differences between visible/IR spectrum. There are plenty of others as well. Oh, and the fact you can access so much of the raw data to make your own visualizations as you like.

Overall, I think my tax dollars are performing nicely for my interests.

> Overall, I think my tax dollars are performing nicely for my interests.

And for the future scientists and engineers who get exposed to this at an early age!

I dont know the intricacies of stellar physics, but my understand that smaller cooler stars are less stable. Despite an average temperature that is habitable, the variability and EM environment is not suitable for an atmosphere.

Edit: 1) proximity also leads these planets to be tidally locked, which some argue is not conducive to habitability, though I don't find that especially compelling.

2) The local EM environment and solar flares would not preclude sub-surface habitability, but that is true for planets outside of what we consider the habitable zone as well. e.g. life on Europa has been hypothesized, but it is FAR outside the suns habitable zone.

At 138 light years any intelligence in this system would start potentially receiving our radio signals in the next two decades. They’d need a massive radio telescope to hear them though since at that distance even the strongest signals would be extremely weak.

It looks quite a bit bigger than Earth.

I don't think anyone will be leaving that atmosphere with chemical propulsion any time soon...

Just because it's bigger doesn't mean that the gravity is higher.

”Its mass is 3.02 Earths.”

Right, but you also have to account for density when calculating surface gravity.

TOI-715 b has a log g value of 5.0 +/- 0.2. Earth is 2.992.

Good to know. Thanks!

Correct, but it’s mass (weight) is 3x higher than earth’s, and since gravity is proportional to mass, you’d likely be much heavier there. If the radius of the planet was the same as earth’s, the gravity would be 3x higher, but if it’s bigger than earth, it might not be as bad. The formula is g= m/r^2 , where m is the mass of the planet and r is the radius of the planet.

Damn I'm gonna have to get serious about that diet before visiting :'(

r^2 is around 2.3 for the alleged size so it won't be too big a difference.

Yeah, but look at its period:

>>>ts mass is 3.02 Earths, it takes 19.3 days to complete one orbit of its star, and is 0.083 AU from its star. Its discovery was announced in 2023

https://i.imgur.com/ghLnFrH.png

What would gravity be on that thing, it doesnt say what its circadian rhythm is.. so how long is a day, if a "year" is 19 earth days (or is the period in 'day' local-solar-system-days?)

Orbital period is in Earth days. The same as when we say the orbital period of Venus is 225 days even though a Venetian day is longer than that.

It'd be pretty messy to instead define things in the database in object relative terms, particularly when you usually know things like the orbital period with significantly more accuracy than rotational velocity.

Well yeah, Venus is in our solar system.

Thanks, though - I wasn’t sure if we always use a local reference but then au is as local a unit as possible at these scales.

It's probably tidally locked, so the day will be the same as the year.

The gravity on the surface should be 3,02÷(1,55^(2)) times the gravity on earth. It is equal to ~1.257 so it's about 25% higher.

I learned something today :)

Gravity on surface of this planet will be 3(times heavier than earth)/(1.55(radius)^2), so 1.25g, however escape velocity also depends on planet radius so we get sqrt(1.55 * 1.25) = 1.4 earths escape velocity (so 15.7km/s). Assuming Isp specific impulse of engine of around 300s, let's compute m0/mf (initial mass of rocket / payload) = exp(vEsc/(Isp*g0)) (g0=9.8m/s^2 (on both planets)):

For earth, it's 45.

For this planet, it's 208.

So, the rocket (using our current chemical engine technology) needs 4.6 times more fuel than on earth. Much more difficult, but maybe possible...

edit: formatting

We also have to consider the thickness of the atmosphere. I presume a planet with 1.5x the radius of Earth and 3x the gravity would have an atmosphere that is far more thick and any rocket would have to contend with a significant amount of drag.

Plus, if it would take something like a Saturn V just to put the mass of a potato into low orbit I could easily envision an extraterrestrial civilization thinking it wasn’t worth the cost to try.

> I presume a planet with 1.5x the radius of Earth and 3x the gravity would have an atmosphere that is far more thick and any rocket would have to contend with a significant amount of drag.

I'm sure that's true holding all else the same, but all else isn't the same.

Maybe it's airless due to stronger stellar winds.

Actually, the atmospheric drag is not a big challenge. Yes, it is a consideration of course, hence the payload fairing etc, but much larger problem going to orbit is getting speed.

That's why it doesn't really help much to launch rockets from a balloon -- getting there is not a problem.

See also the Jet Propulsion Lab’s gorgeous Visions of the Future posters:

https://www.jpl.nasa.gov/galleries/visions-of-the-future

The tool has been around in some form since 2007ish, though the latest update was probably within the last decade. The age probably being why it's not so heavily advertised anymore compared to new activities.

I've always been more partial to exoplanet.eu though: https://exoplanet.eu/catalog/toi_715_b--8668/. It's not quite as prettied up but it's usually more practical in presentation.

I personally prefer the Caltech Exoplanet Archive, which has downloadable datasets, APIs, and also presents everything in one shot: https://exoplanetarchive.ipac.caltech.edu/

exoplanet.eu also has downloadable datasets (from CSV to database exports) and an API. The Exoplanet Archive is great if you need the exact e.g. photometry data every time though.

Thanks, there's so many resources tucked away in obscure places that there's probably a dozen more cool things like this that never get noticed.

I like dronecopters!

0.083 AU means that its sun would be huge in its sky? But it's also smaller so maybe not...

In general, a lower temperature star (3075 K versus the sun at 5778 K) will appear larger in the sky on a habitable planet.

I'm getting about 3x the angular diameter of the Sun from Earth, so not particularly huge.

This was quite a bit more helpful than the paper itself, thanks.

Reply on news.ycombinator.com