Hacker News Reader

Hacker News

Comment by MauranKilom | Hacker News Reader

Parent Full thread

MauranKilom

I strongly recommend clicking the "lightspeed" button in the bottom right at some point.

You thought scrolling was slow? Wait until you experience the solar system at the actual speed of light.

View on HN

Thanks for pointing that out! Lightspeed is really S---L---O---W isn't it?

I'm pleased he still loves Pluto.

Me too. Pluto will always be a planet to me!

Related: I find it annoying that we went through the trouble of downgrading Pluto, but we still count any rock that orbits a planet as a moon. If planets have 69 moons, then it becomes tedious and I quickly lose interest in learning about them. I wish there was a definition that included our moon (obviously), made sure that Mars has at least one moon, but limited the number of moons that Jupiter and Saturn have to a handful.

Criteria could include: size or weight relative to the planet, distance to the planet, apparent size in the sky.

I had never thought about that. I just googled to find out Jupiter has 79 moons? WTF…

According to this website, there are dozens of "moons" that orbit 10 to 20 million of kilometers away from Jupiter and have diameters between just 1 and 10 km. It's time for a change of nomenclature!

https://theplanets.org/moons/

When I was in high school there were about 50 moons in the entire system. There were zero exoplanets now, there’s thousands today.

I'm happy that we're finding ever more exoplanets! I remember, as a kid, that there was speculation as to whether they even existed.

I'm less happy about the moon inflation in our solar system. It's pointless. I honestly find the claim that Jupiter has 79 moons misleading. A 1 km rock orbiting 20 million kilometers away, really? It's so far removed from what our moon is that we should not be using the same word to describe it. It's fine to call it a satellite.

So does Saturn. At least, maybe not exactly the same number, but a number just a large

Either Pluto is a planet and Eris and Haumea and Makemake and Sedna and.... are too or you let go of what they taught you in elementary school and be fine with the dwarf planet designation.

I saw a Twitter post the other day showing the orbit of planets in the solar system that included Ceres. There were tons of replies saying "What's Ceres? Did they discover a new planet?"

People would probably have a better idea about our solar system if we taught them that we don't know how many planets are in the solar system, and told them we were going to have some extra focus on the 8 largest (or 13 largest, or 7, wherever you want to draw the line).

The IAU definition of planet (which wasn't the original proposal, and which most planetary scientists don't seem to follow) appears to be a conservative attempt to keep the number as close to the "traditional" number as possible, even if it leads people into having an overly simplistic conception of our solar system. And it leaves us with a loose definition that specifically states it only applies to our solar system, and doesn't apply anywhere else in the universe.

Wow, that was even more eye opening. I've always tried that website at impossible speed..

Eight and a half minutes to scroll to Earth?

Is it just me or is the speed of light slow? /s

But seriously I always "knew" in the back of my mind that the universe is huge. But to have to wait 8+ minutes to scroll from Sun to Earth at the speed of light gives a new earth-shattering perspective.

What’s really bizarre is from what I understand is those photons spend something between 10,000 and 170,000 years bouncing around colliding with stuff inside the sun. From there it takes a mere 8 minutes to get to earth. [0]

[0] http://www.astronoo.com/en/articles/journey-of-the-photon.ht...

For the photons, any travel is instantaneous, and the Earth is just at the side of the Sun.

And then over 2,000,000 additional minutes to pass the nearest photon-emitting (as opposed to reflecting) object in the best case.

Technical nitpick (but HN loves these) - the gas and ice giant planets do emit photons, in the infrared, where the energy comes from gravitational compression. Neptune in particular emits 2.4x as much energy as it receives from the sun.

Traveling at the sort of speed we can easily imagine as "fast", say 150km/hr, it'd take 115 years.

The fastest travel speed we can really understand is about the speed of sound (jet travel), most westerners have travelled at that speed.

At jet speed it takes best part of a month just to get to the moon, to get to the sun takes 17 years. To reach Neptune you’d have to have left about the same time Columbus visited America.

>The fastest travel speed we can really understand is about the speed of sound (jet travel), most westerners have travelled at that speed.

To be pedantic, no, not really. Commercial jets can travel at speeds up to 955 kilometres per hour (593 mph) (per wikipedia). The speed of sound is roughly 1235 kph (767 mph). Also note that commercial jets usually travel slower than their maximum speed to save fuel.

Reply on news.ycombinator.com