New Mars Forums

Much closer recent pictures from Opportunity's panoramic camera show that some of the channels don't end in those shadowy recesses (but most do).  Also, they don't have much ridging or piling of fans or deltas at their base, indicating that the dust there is probably loose and not crusted or frozen.  So, if water created those channels, they're probably not currently active.  I'd like to get a good look in those fissures, though.

If Opportunity only had a flashlight!   :realllymad: 

Does the rover have power to take pictures when the sun is at a shallow enough angle to shine into those cracks?  It would involve operation on battery power alone, sucking up run-time from the next day, but might be well worth the effort.

PS: Rxke is right.  "Do you care if you come back alive?" is a typical no-brainer psych-test question.  I'm just surprised that they claim there's a 1% that answered "no" and was still accepted to the astronaut corps.

http://marsrovers.jpl.nasa.gov/gallery/ … ]Panaramic Camera Photo from Sol 277

This closeup reveals that the channels are dust filled.  That accounts for much of their color.  Some of the channels run through sections much flatter than the rest of the cliff, and the rover may be able to reach them. 

Something interesting is visible in this image.  Follow each channel to its source: Don't those look like small holes in the outcrop at the head of each channel? 

Also, I had assumed that the layer above the formation with the channels was broken by an impact shock.  But what if the culprit was thermal stress from freezing water instead?  It would explain why the top layer is shattered while large sections of the lower layer appear intact.

Yes, Spacenut, a solar oven is a good idea, too.  It'll add mass, but the simplicity might be worth it.

Well yes, John, but we're talking about people expected to live long enough to have adult children.  :laugh:

There are still people who raise their children this way. 

There are still people who realize that allowing eight hours of television & video games a day is a form of child neglect. 

There are still people who realize that building the balance and stamina needed to climb a tree requires climbing it in the first place. 

There are still people who realize that children must sometimes be punished as well as rewarded. 

There are still people who realize that creativity and deviancy are different things in spite of equal risks for both. 

And there are people who turn those realizations into action.

They just learn to hide it.    :;):

Preliminary data is sparse.  However, Titan appears fairly flat, Norbert.  A tidal rise anywhere close to 34 meters in a global scale ocean - even less than a quarter of that - would show up as apparent changes in topography every time Cassini passes.

Let's see if you're right.  (It should show clearly enough.)

Unfortunately, these are socially competing impulses.  Society doesn't want people to think of killing other people as merely trash disposal.  Society also doesn't want criminals, to the point where it will sanction killing to prevent them.  The interplay of the two leads to much hair splitting.

I always try to remember: Executions, like funerals, are meant for the living.  It's a realization that cuts through a lot of the extraneous crap surrounding this issue.

Hello Cindy.

I’d have never thought something like this would work.  However, I went to the library, read the article, and it appears solid.  Varying the tidal force tension in a tethered satellite can be an irreversible process, and it appears the change in potential can be applied to propulsion. 

(The reviewer's link posted is in error.  According to the original article, this effect can be used to provide propulsion up and down.  It is not just useful for de-orbiting maneuvers.)

Who knew?

I also conducted my own preliminary analysis of the technique, and have some thoughts. 

First, the figures given for how much the orbital radius can be changed are very dependent on the orbital radius at which the engine is run.  More acceleration is available in more intense gravitational fields, meaning that a vehicle using this propulsion method would perform best in low earth orbit.  Also, the model used in the article is very simplistic.  The vehicle wouldn’t necessarily get the best response when aligned pointing at the central body but rather along the local gravity vector.  It can be used in interplanetary space, too.

The article doesn’t make much of it, but my analysis suggests the response is very velocity dependent as well as length dependent.  The faster you spin the dumbbells, and the longer their tether, the more thrust you can get.  It should be possible to easily rival or exceed the thrust of ion engines with a high enough operating speed and long enough rope.  And the effect is mass independent.  The mass of the spacecraft only affects the motor speeds attainable, not the thrust for a given motor speed. 

Also, a spacecraft doesn’t have to use just one dumbbell.  Multiple systems can be used to  increase thrust.  A ship could conceivably built, juggling dozens of ascending and descending motors, with enough thrust for manned missions.  A solar powered system requires no fuel, and uses current technologies rated for multi-year operation and readily repaired in the field. 

This could be an excellent means of propulsion for a space bus or space station. 

This is just too cool!  Thanks for bringing it to our attention.  :up:

Re: Osama bin Laden and the US presidential election...

When I give a darn about what bin Laden thinks, I'll get back to you. 

As for who to vote for on Tuesday, I can't offer a fresh take to anyone, because my own decision was made by Benjamin Franklin two hundred years before I was born:

"They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety."

Unfortunately, I believe that my state Department of Health and Hospital has begun requiring an entry for "Political Party" on children's birth certificates.  The outcome of the election will be entirely determined by the 10% of our population that decline to answer.

I am reminded of my sister, Anna.

Anna had epileptic seizures as bad as that fellow Rxke mentioned.  They were slowly killing her.  Medication helped some, but not enough, and changing medications after her tolerance passed safe limits was always nerve wracking.  Once she got into a medication trial, and it was discovered too late that one of the side effects was that the medication somehow triggered status grand mal seizures when withdrawn or tolerance was reached.  Of six people in that trial, she is the only survivor.

She considered vegas nerve stimulation at one point, but the surgeon decided her seizures were too extensive to expect it to work.  He referred her for an experimental brain surgery.

She ultimately had the surgery.  It worked.  She recovered remarkably quickly, and the only side effect was some lost peripheral vision.  She still has a petit mal seizure three or four times a year - just enough to keep her from getting a driver's license, unfortunately - but medication keeps them mostly under control.  She's even a likely candidate for VNS now, but I gather she's had enough people cutting on her for a while.  Perhaps later.

I'm curious.  Was your husband's response to VNS immediate, or was there a "winding down" period for seizure frequency?

Try a web search on subjects "Cryptozoology" and "Orang Pendek".

Cryptozoology is on the fringe, but not everyone chasing some mysterious legendary creature in the bush has been certified insane yet.  Orang Pendek is a legendary creature from Borneo and the Asian mainland with attributes similar to Ebu Gogo and your "hobbits".  There is a slim possibility that these creatures are contemporary, not extinct, and not limited to Indonesia.

So, technically, when you vote for your local member of parliament, you're voting for prime minister at the same time. 
How cool!  I'd have loved to see one of my local congressmen as president.

Advantage may be too strong a word.      

However, in an important sense we do elect our president separately.  The US Electoral College is still technically a legislative body independent of Congress.  It includes no congressmen.  Its members are chosen by the states, not congress.  It meets only once every four years, it's only function is to chose the president, and - technically - it could vote any way it wants. 

Recently, state laws (not national laws) have turned it into little more than a rubber stamp for the states' votes (which are weighted according to the number of congressmen that state has), and there are a lot of very credible arguments for eliminating it and just allowing each state government to place its vote directly rather than sending dignitaries (the electors) to do it for them.  Unfortunately, someone has come up with the idea that US voters can only understand addition, not multiplication, so that's unlikely to happen.

One person, one vote is apparently all the poor, ignorant plebes can understand, and the only way we can justify more than one vote is to send more than one person.   

It does raise a question, though:  Isn't an intermediate, rubber stamp vote equivalent to a direct vote?