Recent content by Ian J.

I don't remember anything in the quote I read about looking near the sun. I seem to remember it was about looking out into space, in much the same way as Tim Peake did, and being surprised at how it wasn't the deep black he'd expected but was bright with stars (and I'm paraphrasing all of that)...

Re Olber's Paradox, as I understand it that was conceived well before anyone had been to space, and even well before any of the recent discoveries about the state of the universe (not least Hubble's work on redshift and the expanding universe). I suppose it can be used to provide a background as...

OK. I'm slightly confused. A good number of years ago now I read somewhere a comment from one of the early astronauts (I think back in the 60s) that when he saw space for the first time, he was surprised at how much brighter it seemed when compared to being viewed from earth, such that it didn't...

:thumbs: Thanks for that, that's actually quite a reassuring answer :smile:

Hi, Dumb Question #1251: What I understand so far (which maybe incomplete or wrong): in any system with multiple objects orbiting a larger body (either star+planets or planet+moons) each body can have an influence on the others, such that large bodies such as stars and big gas giants have...

So for basic particles, no use. What about solar radiation?

While thinking about the recent-ish developments in meta materials for 'cloaking' systems, a thought struck me: could a meta material or combination of meta materials (probably of a somewhat more advanced state than they currently are) be used as a form of shielding from cosmic rays of various...

OK, that explains a lot, thanks! :)

I didn't mean 'disappear'. I suppose 'short lived' was a poor choice of words on my part. I mean that the heat that is keeping the gases expanded, if coming from inside the planet, must be being generated by something and I'm presuming it's an internal process rather than an external one...

So temperature could be considered the local condition affecting Kepler-7b. How much volume expansion of the gasses can the temperature cause? What is likely to be the maximum volume of gas giant before the temperature can't push out the gasses any more? I'm also presuming, with such...

I think I've got it now that I've had a bit of sleep. The universe, being as big as it is, and the expansion being percentage-based and applicable everywhere, means that over the distances we're talking about the effective expansion gap 'speed' can be big, in your example ~3c. I suppose, given...

That's big by mass, not big by volume which is what the thread is about.

I've no problem with the expansion not breaking 'relativity', as the simple example of two objects moving away from each other at, say, two thirds light speed, create an expansion gap 'speed' of one and one third light speed (that's not counting universal expansion underneath them, now that...

I kind of get what you're saying, but I'm still not quite sure if I understand it. I think I'm tripping over the thought in my head that says the universe is approx. 13.7 billion years old and I'm pretty sure that it's not expanding at the speed of light (or anywhere near it), so how can...

True, but my question was just how big could a gas giant get. I suppose I need to add that the local conditions might need to be defined too, if they can have a significant effect.