Really interested in this discussion. I too know nothing of orbital dynamics, but the above wasn't always the case was it?

The moon is becoming more distant at about the rate of 4cm a year - roughly the rate your fingernails grow so back before the dinosaurs roamed the Earth the Moon was considerably closer to the Earth. So why did the Moon not become locked in an equatorial orbit?

Neil

With the solar system being roughly coplanar, we might expect that the impactor that formed the moon would have come from the same solar system plane and thus the debris (proto-Lunar disk) would be in roughly the solar system plane, and consequently the Moon as well.

Maybe it got locked soon after it's formation but then gradually unlocked as it moved away??

I apparently misread the post I replied to earlier.

The Moon isn't in a perfectly equatorial orbit because of various gravitational effects on the Moon (the sun, others), causing its orbit to vary on fairly short timescales.
So, ngunn is right. At first, the Moon was too deep in Earth's gravitational well to be as severely affected by these various perturbations, but as it drifted out it became more subject to them.

ADMIN: Moved from this thread. Pointless initial comment and perfectly valid replies ignored.

I certainly agree that these are beautiful images, but I swear I can't see nearly as many blueberries - in the rock matrix - that others are implying in this and other threads. What's wrong with my eyes?!
Is the emperor in his birthday suit or no?
Help!

Who's mentioned berries in this thread? I can find no reference.

You're right, Stu. I should have taken the time to carefully read the comments. In this thread no one is counting blueberries except me. And I'm getting very low counts. Am I the only one? You've stated in the other thread I just came from, that Ruiz is "bleeding berries". I see nothing of the sort. I'd like to poll the jury on this issue. Is this a reasonable request?

Honestly, you're taking my clearly flippant comment 1) far too literally and 2) far too seriously. Go back to the other thread, see the pic with emerging berries actually ringed to make them easier to see, read my absolutely amateur take on it, then let that bee fly out from under your stone bonnet

I anticipate that driving, as well as official site updates (and maybe even site access), will take a hiatus for lack of (fiscal) fuel. Let's hope for a very short pause.

REMINDER: no debates about the underlying cause. Just wanted to alert our non-US readers that barring unforeseen changes, all non-essential US Government functions stop tonight until funding issues are resolved.

This same scenario interrupted the Galileo entry probe science transmission... grrr

Maybe not:

"Because JPL is managed by the California Institute of Technology, its employees are NASA contractors, not civil servants; they would be expected to work through a shutdown, JPL spokeswoman Jane Platt said April 8. "We will keep working," she said."

http://www.space.com/11344-nasa-government...00-workers.html

Edit:
Scott's not sounding worried
Per-sol drive distance limits lifted for Opportunity -- and we have a sol coming up where we can take advantage of that. Maybe 160m/sol!

Definitely not. JPL will be open for business as usual.

In any case, the law allows work involving the securing of life and property to continue. Missions that are actually "flying" are considered to fall in that category.

From Florida Today:

Q: What effect would a government shutdown have on NASA, the space
program and workers at KSC preparing for the April 29 launch of Endeavour?

A: NASA headquarters said the agency will "take the steps necessary to
maintain the safety of our astronauts in orbit and ongoing mission
operations for the International Space Station and our other ongoing
science and space missions."


ADMIN: Folks, let's not stray into further discussion on this topic.

Feet, pounds, miles... I just love those old Imperial units.
They are filled up with dusty memories.
But it's a pity they are still used today in the USA.
One can hope they were not used to design the MSL mission...

Why not? One unit of measure is the same as the next when used consistently and accurately. The modern industrial civilization that we know today from the 19th and 20th centuries was built using those units of measure. The problems come when a careless person transposes between respective systems. Of course, MSL wasn't built using those units, but even today in the era of not just calculators but complex computers at everyone's fingertips the convenience of the metric system is not necessarily the advantage that it was when engineers were writing equations by hand to solve problems. The programs that calculate complex orbital trajectory would work just as smoothly in furlongs per fortnight as long as all the units were correctly defined.

So that would never be a problem if they stopped using two systems and settled on a standard! The problem isn't what the system is. It's just that having two systems in use is asking for trouble.

Well, to be fair, Dan is right. There is no such thing as a baseline standard of measurement. Remember that the meter was originally defined with respect to a rather arbitrary physical reference: 1 x 10 exp -7 the distance from the Earth's equator to the North Pole. This was almost certainly at least a subconscious homage to Earth's "special place in the Universe", and therefore not based on anything remotely resembling a mythical absolute standard.

Not intended to be a defense--or an assault--with respect to ANY system of measurement. The real point here is that everyone in a complex endeavour had damn well better be working from the same set of same. I think that the unfortunate failure to follow this glaringly obvious (in retrospect) heuristic a few years back provided an enduring lesson that is unlikely to be forgotten--or repeated.

(FWIW, even though I'm an American I'm a HUGE fan of the SI protocol...I doubt that I would have survived my physics courses without it, to say nothing of any other discipline that demands intensive calculation. Base 10 makes all kinds of sense to us goofball humans, and that's arguably the most powerful reason to embrace the metric system.)

I'll echo Nicks comments and add that in my own work I've found that going to using the log values and log scale is a really good way to highlight relationships and avoid over-interpreting data.
So whatever measurement system is used, it's gotta be in multiples of 10.

Hi Tesheiner

Awesome job on the Maps. I know you put KM marks on your map but can you also put mile marks when possible. Us Americans are still old school
and use that still.

Thanks.

I'm pretty sure Tesh has more than enough to do with keeping the maps updated as often as he does, Bobby. You can do the km/miles conversion yourself very easily, you can even use the Calculator that comes with Windows.

Easy guideline for converting anything to anything else: "Measure it with a micrometer, mark it with chalk, cut it with an axe."

Micrometer: miles = 0.62137119 km

Chalk: 2/3 km, then 10% less

Axe: 2/3 km

Then you can figure it out for yourself. I'm sure you know how.

Why not figure it out, add them, then share it with the rest of the forum - rather than asking someone who already spends HUGE amounts of time giving you amazing resources for nothing, to do even more work.

Chainsaw: 0.6

Gotta admire your work ethic, Bobby

I am sure Bobby has enough constructive advice to be going on with for now. Thanks everyone for your input.

Let's get back to the subject of route maps now, ok?

If I'm right the 2 bold lines we're very close to, crosse at 10 km East and 16 Kms South from Eagle, while Spirit's point is close to 11km East and 17 Kms South.

It is 9km and 10km E, respectively.

hum hum
Google Mars give me 17,702 km in strait line to Eagle, it can't be 9 & 10 Eduardo.

"17,702 km"

Are you sure that wasn't to Deimos?

Phil

Again this measurement issues
The coma separates kms AND meters here in Europe.
So I should have written 17702 meters... but I like your reply

That's an interesting way of putting it rather than saying the coma in Europe replaces the decimal point used in the US. But then you would have to write: 17,702 km,m

Ok thanks. I'll paid more attention next time
Now, I'm still interested in knowing where we are from Eagle.

Here's an overview of the region with a 1000 m grid superimposed. There is always a slight variation between images like these because of relief distortions etc. so this is close to Tesheiner's grid position but not exactly identical. But it allows one to count grid cells quite easily.

Phil

Click to view attachment

Thanks Phil, very handy.
This confirm 16S/10E

Mmm, really?
Click to view attachment

I'd said we are both wrong
Can we agree Spirit's point is very close to 17 kms South and 10 km East of Eagle?

I'll be very happy to be put right on this from those with a more scientific background than myself but I think when Climber refers to Europe in this example he is referring to continental Europe rather than including the UK. In Britain, I would hope I could speak for the majority in saying that I would read 17,702 km in the same way it is read in the US rather than the European interpretation. That is to say as nearly 18 thousand kms as opposed to nearly 18 kms.

This is not to say which is right, just commenting on how data is interpreted/shown in different ways.

Neil

17.702 (USA+UK) = 17,702 (continental Europe)
It's similar problem as miles vs. kilometers, or short scale (billion = 1 000 000 000 in USA and UK) vs. long scale (billion = 1 000 000 000 000 in most continental European countries).

I remember the preference being 'thousand million' instead of billion.

deceived?

disappointed I mean... a false friend between French and English

Junk Drawer? I guess this one fits right in here:
New Solar System Discovered Four Feet From Earth

This is how I know the story is fake. Van Nuys is 350 miles from Palo Alto.

Despite what has popularly been stated, there may (or may not: an old discussion) have been standing water at Meridiani, and there probably was acid water (or at least volcanic or impact-generated steam), but it's highly unlikely that there ever was standing, acidic water for any significant time period anywhere on Mars, because it would have been neutralized by the broken fresh basaltic rock that litters the surface and constitutes the fractured crust. This is elementary high school chemistry. Even hematite dissolves in acid.

As Roger Burns noted long ago in proposing jarosite formation on Mars, acid salts such as jarosite are a form of crystalline or fossil acid. They indicate that ephemeral acidic waters (or steam) have quickly evaporated or been frozen before they could react with the rocks around them. This is an old observation for UMSF, already discussed extensively, that I repeat here only for newcomers. No further discussion is needed.
- dburt

The Oxford dictionary defines water as a colourless, transparent, odourless, liquid which forms the seas, lakes, rivers, and rain ..... By definition the other H2O phases, ice and vapour, are not water. Ice and water vapour have been identified, but to the best of my knowledge water has not been detected on mars other than maybe perhaps on the Phoenix strut which was not a native Martian event and really should not count. But the evidence of water in the past, of varying pH, is pretty convincing.
The elementary high school chemistry argument is something of a red herring. Early on Martian water may well he had a reasonably high pH. In the later, volcanic period then it is true that acidic water weathers basalt and basalt buffers acidic water. But in a system where acid is being constantly replenished by volcanic influences then regardless of the presence of basalt we can end up with acidic water near the surface and deeper alkaline water. The plethora of potential mixing relationships can result in products such as hematite concretions and Calcium sulphate deposition.

Umm. If we're going to get historical, let us certainly not forget the directly-observed-and-mapped-by-famous-astronomers canals of Mars, or the still observed annual color changes, which everyone once "knew" were caused by seasonal changes in water-fed vegetation (as on Earth). When it comes to putative evidence for water on Mars, past OR present, I think a whole lot of humilty is called for, even among those who pontificate anonymously on this forum. (And, before anyone gets upset, I could be thinking of the evidence allegedly provided by young gullies here, on which I personally published several probably-mistaken papers about 10 years ago, instead of that allegedly provided by Meridiani cross-beds or spherules. In the case of gullies I basically went along with the conventional wisdom, and appear to have been wrong.)
- dburt

[MOD]: And this post is a contribution to a list from credible sources as defined by EGD how?

[MOD]: And this post is a contribution to a list from credible sources as defined by EGD how?
If anyone wants "a list from credible sources," just look at the above-mentioned Wikpedia article "Water on Mars" (most recently modified by someone today, 2/10, incidentally) and be done with it. And you can add to the Wikipedia article yourself, if you see that it's incomplete. Instant credibility?

The purpose of my "need for humility" post was simply to note that today's "credible sources" regarding evidence for water on Mars can easily become tomorrow's "known to be spurious" sources (with considerable overlap in timing possible, depending on who is doing the writing). The canals or alleged annual vegetation changes are the best-known examples, safely in the distant past, so that all the scientists involved are dead. The "young gullies" feature (see posts 1 and 5 above), discovered from orbital images in 2000, could well turn out to be another dud (and I was directly involved in that discussion, probably on the wrong - wet - side). In regard to gullies, for example, Richard Kerr's AGU "Snapshots from the Meeting" summary in the 12/21/12 issue of Science discusses "New evidence that changes in the appearance of martian gullies from year to year are the result of carbon dioxide frost (aka dry ice)".

So no list of evidence for past or present liquid water on Mars, no matter how elementary, would be complete without noting that the evidence, in many if not most cases, is equivocal and subject to changes in interpretation. That is, valleys, gullies, and conical debris aprons can be formed by various types of flows, rocks can be rounded by any type of friction or certain types of weathering, hydrous minerals and salts can form in hot steam as well as in lakes and seas, cross-bedding forms in many distinct types of flow environments, spherules are formed by a huge variety of geologic processes, the temperature stability of liquid water with regard to freezing or evaporating/boiling can be modified by a variety of solutes, and so on. That is real nitty-gritty science, not press releases or greatly simplified Wikipedia articles.

For Mars, the direct observations (e.g., young gullies and debris aprons) remain valid as interesting scientific discoveries, but the human interpretations (e.g., evidence of recent water flows) are invariably subject to our prior experience and expectations. Possible observer bias and the influence of expectations on scientific outcomes (e.g., involuntarily making what becomes a self-fulfilling prophecy; we expect or hope to see evidence of X, and therefore we do) is a subject much studied by psychologists such as Robert Rosenthal, and regarding which there are many articles in Wikipedia and elsewhere. I hope you agree that this general topic (basically, urging caution in interpreting the evidence) is relevant, especially given its well-documented prior history in martian water studies.
- dburt

Thanks dburt. Doing good science is a difficult process--interpritations are tricky--ultimately science is self correcting, but it can take years. I even appreciated the humor in your understated post #16

Couldn't agree more. There are an awful lot of conflicting hypotheses on this subject from credible sources (in terms of credentials, experience and position) and this is quite right and proper. All possible explanations for observed phenomena must be considered as the evidence is sifted. But proof is a different matter. There is certainly proof of ice and proof of water vapour on Mars and with Phoenix we actually saw the transition in phase on the mirror. But there is no proof of existing water. With apologies to EGD, in colloquial use ice and water are different things and since the initial request was directed to a talk to schools and general public the semantics are somewhat significant.

And I didn't say the phases weren't relevant, I said THIS TOPIC isn't the place to compare, contrast and debate them. If someone wrote a paper, or if some agency held a press conference, they almost certainly would have made that distinction -- liquid, ice, vapor, gas or whatever -- with regard to their "discovery".

All we were looking for in this discussion was a LIST of "discoveries" not a discussion of them.