This is a hard problem.  I am unaware of any tools that do this. Computing the path and travel time for a Hohmann transfer (smallest delta-v path from one orbit to another without assists) is fairly simple, as is the path under constant acceleration and the assumption that the peak velocity is high ...

Back from another mineral-hunting adventure.  This time the objective was quartz crystal. Inside a "crystal cave".  No, not a vug.  Manmade, this claustrophobia-inducing tunnel was dug beneath the stump of an old logged tree.  The whole area is a slump zone, and the roots catch crystals as...

30316 When observing a pulsar from Earth, can we determine what the angle between the rotation axis and magnetic axis is? A late answer, but the answer is yes, this can in fact be done!  The method is outlined in section 2 of the paper  On the Evolution of Pulsar Beams  by Tauris and Manchester (19...

This is a very good question.  An important combination of physics and philosophy. In my view, I think there must be the capacity to make mathematical descriptions of all physical properties. A physical property is (in principle) a measurable one.  It is some aspect of nature that is present has som...

Nice catch.  They were over here as well last week.  Saw them low in the north driving past Seattle in the morning.  Didn't get any pictures, though.

30052 The exoplanet found, called Teegarden b, has a minimum mass almost identical to Earth. I hate to dim the excitement, but I think that this part is important to emphasize.  When detecting an exoplanet by radial velocity measurements, the strength of the signal (how much it tugs its host st...

PBS Space Time's latest video on how supermassive black holes extend their influence on and even beyond their host galaxies, to have far-reaching consequences on star formation.  It's also a nice review of the M-sigma relation (the surprising connection between the mass of the black hole and its hos...

Those are seriously impressive!  I feel like these could be photos from an Apollo mission.  The focus and atmospheric turbulence look perfect on the second shot, which supports the sharpening.  

JKerman, looks good to me!  Nice find.

29697 but I am having trouble with the whole thing about "the universe not filling in originally empty space as it expands", mainly because you didn't state why "the universe doesn't rearrange the distribution of internal energy or matter". You're not alone with having trouble w...

Giving hard rock mining a try.  There's a marvelous spot hidden up in the hills nearby where veins of blue translucent agate/chalcedony run through volcanic rock that's tough as nails.  It's some of the most intense color I've ever seen in a stone. I spent a good portion of a day working at it with ...

29525 How do irreversible processes relate to entropy on a microscopic scale? I'm having trouble visualizing this on a universal scale. Irreversible processes involve changes that can't be undone (go in reverse) as easily as they happened forwards, which is equivalent to saying that they increase t...

29498 so the amount of entropy can be measured by calculating the volume of a system Not necessarily, and in fact this doesn't work with the expansion of the universe.  Let's look in a bit more detail.  In some cases, such as gas expanding to fill its container, it is true that the expansion is ass...

29483 Just after a Big Bang. The universe is very small and hot. It would reach thermodynamic equilibrium long long before today. Aye, it was very hot and dense and low in entropy.  But it was also expanding very rapidly.  That expansion combined with gravity are what we need to think about here. T...

29446 Entropy in a system will always increase, as per the Second Law of Thermodynamics. Increasing entropy overtime in a system is the natural result of that system existing. Entropy of a closed system can also be constant.  Example:  An expanding universe filled with photons is isentropic,  or ha...