Recent content by Jonathan Scott

My Panasonic Lumix TZ200 ("travel zoom" camera, compact with up to 15x optical zoom) is very convenient to carry around and has a viewfinder which is very useful on sunny days. I spotted a butterfly which was too far away for me to identify immediately but this photo clearly identifies it as a...

We visited Exbury Gardens (in Hampshire, UK) a couple of days ago. It's an amazing sight all year round, but in rhododendron and azalea season it's quite overwhelming!

For a different strength of gravity, atmospheric pressure and hence density would be expected to be different too (unless in a closed container), giving an additional small buoyancy correction that would actually vary with gravity.

I'm wondering whether the second stage subsequently managed the third (disposal) burn. If it did, then in hindsight it might have been better to have deferred payload separation to have a second attempt at the second burn (needing either very intelligent automation or very flexible control). If...

True of course, and presumably relevant in this case, but to avoid confusion this needs to be accompanied by the important point that if the angular size of an individual object (such as a star) is smaller than the sensor or eye resolution then the apparent brightness is decreased accordingly...

Thanks - I knew that the colours were completely artificial and Hubble photos include wavelengths outside the visible spectrum but I had assumed that some similar shape would be visible. (One can for example see the Andromeda galaxy unaided on a dark clear night, which is a lot further away). I...

That's getting a bit off topic, but from some quick Googling, that image is probably of the order of 5 light years high, and the version of the image you've chosen is about 620 pixels high. The angular resolution of the human eye is about 0.0003 radians, so if you for example wanted that to...

The human eye adapts well to darkness, although it doesn't see colour well at low light intensity. The earth was lit by full moonlight. If I just save the darker image and "auto-adjust" colour I get quite a similar result, although the available copy of the darker image is lower resolution, so...

No it isn't. That looks like a launch from complex 40 (Falcon 9) not 39B, but in any case that picture is quoted in a post by Chris Hadfield from 2024.

That article now contains a more realistic acceleration (around speed of sound after a minute) and the following at the end:

I've never liked live classroom lectures, as the speed is rarely right for me. Most of the time it's far too slow, but occasionally I find an interesting point and wish I could think about it more. So from that point of view, I've always preferred learning at my own speed from written materials...

I wish we had someone around here (UK) who wanted my Encyclopaedia Britannica! I've been trying to donate or sell it for years. It's 15th Edition, 1989 revision, plus all year books from 1990 until they stopped in 2012, plus "Science and the Future" volumes and "Medical and Health" volumes...

That brings back long-archived memories! I think I had ids on BITNET and JANET at least. I guess my ids must have expired after I left the Gothenburg Universities' Computing Centre in 1987 to join IBM.

That doesn't sound like an ethical solution to that situation!

I think "exactly" is a clear enough condition here. It means that the result is three equilateral triangles and nothing else.