Brown dwarves are cool!

Nah, seriously, they really are cool. Some of them are cooler than Venus, and they don’t fuse... not even deuterium. In fact, some red dwarves don’t come anywhere near the temperatures required for fusion (roughly 10⁸°K standalone; with the help of a few other factors, maybe 3,000,000°K), which raises an obvious question.

Why do they glow?

At all?

“Gravitational collapse” can only get one a part of the way towards an explanation. In fact, Chandra detected a brown dwarf throwing a big Xray flare in 1999, which presents an even more stark dilemma. What’s a star (LP 944-20, ≅60 Jupiter masses) that can’t even fuse, that’s gravitationally collapsing (adiabatic compression) doing throwing flares?

Even more MiB: why haven’t we been told that our mainstream astrophysics has many such issues and is well past due for a revolution?

Comments

every-application-is-part-of-a-toolkit at work

I have a LibreOffice Impress slideshow that I wish to turn into a narrated video. 1. export the slideshow as PNG images (if that is partially broken — as at now — at higher resolutions, Export Directly as PDF then use ‘pdftoppm’ (from the poppler-utils package) to do the same). 2. write a small C program (63 lines including comments) to display those images one at a time, writing a config file entry for Imagination (default transition: ‘cross fade’) based on when the image-viewer application (‘display,’ from the GraphicsMagick suite) is closed on each one; run that, read each image aloud, then close each image in turn. 3. run ‘Imagination’ over the config file to produce a silent MP4 video with the correct timings. 4. run ‘Audacity’ to record speech while using ‘SMPlayer’ to display the silent video, then export that recording as a WAV file. 4a. optionally, use ‘TiMIDIty’ to convert a non-copyright-encumbered MIDI tune to WAV, then import that and blend it with the speech (as a quiet b

new life for an old (FTX) PSU, improved life for one human

the LEDs on this 5m strip happen to emit light centred on a red that does unexpectedly helpful things to (and surprisingly deeply within) a human routinely exposed to it. it has been soldered to a Molex connector, plugged into a TFX power supply from a (retired: the MoBo is cactus) Small Form Factor PC, the assorted PSU connectors (and loose end from the strip) have been taped over. the LED strip cost $10.24 including postage, the rest cost $0, the PSU is running at 12½% of capacity, consumes less power than a laptop plug-pack despite running a fan. trial runs begin today.

boundaries

pushing the actual boundaries of the physical (not extremes, the boundaries themselves) can often remove barriers not otherwise perceived. one can then often resolve an issue itself, rather than merely stonewalling at the physical consequences of the issue.

Plantagenet Penguinista

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