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DNA Codon tables are the lookup tables for the Amino acids. Each species has a unique table, though they do seem to vary between species.

DNA is transcribed by converting into RNA with one of the base pairs being replaced by an amino not normally found in regular DNA. I guess that prevents the transcription machinery from getting mixed up.

You can find the data set on the NASA site too, as well as data viewers: http://www.giss.nasa.gov/tools/panoply/

The models require massive amounts of CPU cycles, though. You won't be able to duplicate the results on your PC.

And these days something like computer code.

Here you go: http://simplex.giss.nasa.gov/snapshots/

no, the GP post wasn't a little bit of BS, it was almost all BS. Nimbus 7 was a weather and atmospheric science spacecraft. In fact, with today's technology and the user's guide (which was an unclassified document widely available within NASA - I still have a copy on my bookshelf just for old time's sake) it would have been pretty simple to take it over. You can read the introduction to the Nimbus 7 User's Guide here: http://toms.gsfc.nasa.gov/n7toms/nimbus7tech.html - it was that unclassified. It was a sad day when Nimbus finally died - it was a great program that was responsible for a lot of groundbreaking science, perhaps the most notable thing being discovery of the Antarctic ozone hole.

Now, if I remember correctly, Nimbus 7 WAS built by GE-Astro in Valley Forge PA, which also did a lot of work on classified DOD missions - check out the recently declassified information on GAMBIT and HEXAGON. They had their fingers in both of those programs (perhaps the film return capsules?) which would explain the security at the plant.

Its completely conceivable that even a motivated individual could command all but the most recent NASA science satellites - the only real security they have is through obscurity. However, this is not true about any manned NASA spacecraft or joint missions. Those have had hardware encryption on both the up and downlinks for as long as I am aware of. All NASA science satellites since 2001 have encryption on the uplinks - the downlinks are still unencrypted, so if you had the right antenna, receiver, demods and such, and wanted to reverse engineer the telemetry format, you could.

Motivated by Explorer 1's success, JPL Director William Pickering wanted to move into space exploration. He thought the relatively small, non-profit JPL could never raise the money necessary to remain on the leading edge of rocket technology as much larger aviation companies entered the rocketry business. He convinced the Army and President Eisenhower to make JPL part of the nation's new space agency, the National Aeronautics and Space Administration. In that role, JPL, with its links to Caltech's science community, could lead in the creation of the new realm of space science. In December 1958, the Army formally transferred JPL to NASA, although it remained under Caltech management.

If you're interested, here's the URL: http://www.jpl.nasa.gov/jplhistory/early/joinnasa.php Note the URL, if you please.

tl;dr: Neener neener, you're wrong.

Or, roughly 200 grams of antimatter...

Pfft! That would only cost about 15 trillion dollars to manufacture. Lets make three.

"A rough estimate to produce the 10 milligrams of positrons needed for a human Mars mission is about 250 million dollars using technology that is currently under development"

source

The free NASA "3D Sun" iphone app will give notices of CMEs if you allow it:

        http://science.nasa.gov/science-news/science-at-nasa/2010/17feb_3dsun/

There are a few Android apps that get SDO and other space weather data, but I don't know which ones of those will generate alerts rather than you have to go and actively look at them.

(disclaimer : I work for the Solar Data Analysis Center)

Check out the NASA Space Grant programs as well; they have an informative website with lots of contacts for you to call and ask questions. Good luck!

Check out the NASA Space Grant programs as well; they have an informative website with lots of contacts for you to call and ask questions. Good luck!

Most satellites have essentially no situational awareness, because being taken apart by little aliens in shiny green spacesuits (or by advanced remanufacturing robots) is just not part of the threat model. So it tends to be very hard for ground control to distinguish between a random equipment failure and a failure caused by deliberate modification of the spacecraft.

This mission probably isn't what the X-37 is for, since it's a low earth orbit vehicle, not geosynchronous.

A bright comet fell into the sun on October 2, 2011 in synch with a coronal mass ejection bursting out on the other side. http://www.nasa.gov/mission_pages/sunearth/news/comet-cme.html Just wondering. Solar wind and all.

The code and other information for NASA/GISS's Model E, one of the most prominent General Circulation Models, is located here. They say it can be scaled to run on any sized computer. The "raw and corrected" temperature data sets such as the BEST study examined are not used as input to GCM's such as Model E. In theory they could be started anywhere and converge on reality eventually. The input to GCM's for projections of the future are various scenarios of the variables you are examining with the run such as changing CO2 levels or changes in insolation. If they are hindcasting they will input the real observed changes to those variables to see how well the model models the actual climate. Temperatures are an output, not an input into the models except maybe as a starting point and the starting point doesn't affect the ultimate ending point that is reached unless you pick some ridiculous value.

With regards to a control planet and whether the warming is anthropogenic:

  Mars orbiters have observed greater summer ice cap melting on Mars.

And for three Mars summers in a row, deposits of frozen carbon dioxide near Mars' south pole have shrunk from the previous year's size, suggesting a climate change in progress.

but spending a trillion dollars to win a pissing contest while we're cutting Social Security, selling off parks, and laying off tens of thousands of government employees seems, I don't know, kind of stupid.

A trillion? The cost is estimated in the low tens of billions ( http://en.wikipedia.org/wiki/Manned_mission_to_Mars#ESA.2FRussia_plan_.282002.29 , and http://quest.arc.nasa.gov/mars/ask/humans-on-mars/Cost_of_Manned_Mars_Mission.txt ). By comparison, the entire Apollo program cost only $150 billion in 2010 dollars, the Iraq war cost $1 trillion, and the War on Drugs costs $10 billion every year.

Given that the Apollo program galvanized world opinion in favor of the USA and the values it represents, motivated an army of youngsters to become scientists, and resulted in innumerable technological spin-offs and benefits, I'd say it was well worth it. It will be well worth it to repeat these feats in the future.

As for Social Security, it costs $700 billion every year, but can be made solvent again simply by raising the retirement back to the level it was when the program was first created.

ESA will get there first, with the Atomic Clock Ensemble in Space (ACES), intended for the ISS in 2013, which should be good to ~ 10**-16 and will include a test of relativity. I believe that this is the JPL clock, which is aiming at 10**-15 stability, and a 2015 launch. (Both are fairly low earth orbits, with the JPL clock intended for an Iridium satellite.)

So, the JPL effort is cool, and I would love to see one flown to Mars or truly deep space, but this is one case where the Europeans are in the lead.

Crank calls - and honest mistakes - will happen and will find any "access point" well-enough publicised to actually be useful to Joe Random Astronomer in his dome. So there will be PR flacks that you'll have to get through.

So, unless some group is being specifically employed to carry out searches like this, and have a particular phone line to the appropriate powers ... I don't see it working. (Yes, several navies etc have astronomical services. Most of these are for producing navigational ephimerides, not observational work. Those observations that are done, are focussed on (specifically, for the USNO) ecliptic surveys for NEOs and PHAs, not on performing the multiple-fold whole-sky continuous survey that you're implying.

It's not impossible to do this ; but it's not being done (AFAIK).

There are robotic whole-sky surveys. But they have limiting magnitudes in the 8 or 9 range. For the sort of detections you're talking about, you'll need to go down to magnitude 15 or more. That's a major leap of technology and probably optics.

What's the data processing pipeline for that sort of project going to be like? Say ... a 6 hour imaging cycle ... you'll need to get to something like arc-second resolution, so that's 839,808,000,000 pixels for the whole sky. You're going to have to align successive images (actually, you'd do it by tiles, but WTF), compare them for differences, then detect the interesting events.

Define "interesting" : if I've got my maths correct, you're looking at something 600+ times the coverage of the Kepler mission, though possibly with lower dynamic range. They've got 24 planet candidates, 2176 eclipsing binaries, and who knows how much other stuff. And you've got to sort out your incoming impactor from this lot. In a real-time setting.

Not as trivial as it sounds, is it? You'd probably need to build an astronomical university just to train enough astronomer-technicians to weed out the false positives.

Be a fun project though. Real fun. Make that LHC thing look like the small science it is.

The US navy explored the Northwest Passage around fifty years ago. It didn't stay open for long. The British explored it in the 1850s. The oceans have several atmospheric oscillations with multi-decade periods, these result in alternating warming/cooling cycles. We're in the top of a warming cycle, but the phase has already shifted. This year the ice minimum was two weeks earlier than back in 2007, the arctic ice cap will start rebounding within a few years, and these passages will close up again.

And fifty years or so from now, they'll open up again. For a few years.

The US killed three monkeys and a mouse in rockets before the first successful landing.

NASA is a contractor agency which has a large R&D wing. Generally, NASA doesn't build rockets anymore. Rockets have been assembled by maybe by Boeing and Lockheed Martin, but there are contacts out to others.

http://en.wikipedia.org/wiki/List_of_NASA_contractors

While NASA should receive *more* funding for bleeding edge R&D, like permanent moon base and then Mars, a lot of the money is sent to NASA contractors and subcontractors and subsubcontractors. NASA leverages commercial opportunities and have been doing that since their inception.

Where do you think Integrated Circuits (ICs) come from? NASA private sector contractors. NASA was buying up almost all of the early silicon for the Apollo program. Without these "deep throated corporations", we would not have had computers that we do have today and that is just one example.

Anyway, this is complementary service to sounding rockets. This is not even going to orbit.

http://rscience.gsfc.nasa.gov/srrov.html
http://www.thespacereview.com/article/1228/1

Finally, there is really nothing "special" anymore about flying a sounding rocket, or even getting to LEO. This can be done by commercial services. Where R&D is needed is long term projects like survivability in space, Mars, outer solar system and beyond.

Since when has the search for extraterrestrial life been part of NASA's mandate? And why must the search for life be the sole reason for NASA to launch a scientific mission?

Consider http://www.nasa.gov/offices/ogc/about/space_act1.html

Here are NASA's objectives according to the National Aeronautics and Space Act:

"(1) The expansion of human knowledge of the Earth and of phenomena in the atmosphere and space.

(2) The improvement of the usefulness, performance, speed, safety, and efficiency of aeronautical and space vehicles.

(3) The development and operation of vehicles capable of carrying instruments, equipment, supplies, and living organisms through space.

(4) The establishment of long-range studies of the potential benefits to be gained from, the opportunities for, and the problems involved in the utilization of aeronautical and space activities for peaceful and scientific purposes.

(5) The preservation of the role of the United States as a leader in aeronautical and space science and technology and in the application thereof to the conduct of peaceful activities within and outside the atmosphere.

(6) The making available to agencies directly concerned with national defense of discoveries that have military value or significance, and the furnishing by such agencies, to the civilian agency established to direct and control nonmilitary aeronautical and space activities, of information as to discoveries which have value or significance to that agency.

(7) Cooperation by the United States with other nations and groups of nations in work done pursuant to this chapter and in the peaceful application of the results thereof.

(8) The most effective utilization of the scientific and engineering resources of the United States, with close cooperation among all interested agencies of the United States in order to avoid unnecessary duplication of effort, facilities, and equipment.

(9) The preservation of the United States preeminent position in aeronautics and space through research and technology development related to associated manufacturing processes."

I am not saying that we have the technology today, but if we don't at least explore the idea further (and I am not aware of any such discussions going on in NASA or the rest of government today), then I think we're dropping the ball.

As for advantages, if any of the moon's resources (or even asteroidal or comet resources, for that matter) can be exploited for either construction material or fuel (there is lots of oxygen in moon rock, for example), then that mass would not have to be lifted from Earth. That could be a very big advantage. Another big advantage is the exponential relationship between rockets and gravity: the higher the gravity, the more thrust needed to lift a payload, which requires more fuel, which requires more structure to hold it, which requires more thrust, which requires more fuel... and so on. And to add to that, there is no appreciable atmosphere on the moon to add drag that has to be overcome.

As we saw in the Apollo moon missions, it only takes a very small rocket to escape the moon's gravity well, while it takes a huge rocket to escape Earth's, because of those very factors. And again the last factor is that you have gravity in which to construct things.

If there are any exploitable resources in space, whether that be water ice from comets or asteroids, or frozen oxygen, or free hydrogen, or whatever, it would probably be most efficient to take it to the moon to process, rather than trying to do it in microgravity, or -- far worse -- down at the bottom of Earth's gravity well. And solar energy is plentiful on the moon. Ice can be separated to hydrogen and oxygen for fuel. And -- I had almost forgotten -- it now appears that there is actually a great deal of water ice on the moon. Couple that with abundant solar energy and you have your rocket fuel!

By the time we are finished building a (small) moonbase, will it be commercially feasible to exploit resources? Probably not. I expect some research would have to be done to find efficient ways to exploit the available resources.

I don't have a problem with a mission to Mars, but a mission to an asteroid seems particularly pointless to me. We have done some pretty close fly-bys and we have a pretty good handle on their composition and behavior. Frankly I don't see any real purpose to it. But maybe I've missed something.

Same with Mars. Because of the distances involved even if not anything else, we will have the technology to have a permanent moonbase long before we have the technology to even be going to Mars very often.

I imagine bio-engineering would be the direction to take to avoid that. If scientists can design a self-replicating micro-organism to extract oxygen from the soil and release it (and then die without leaving something toxic behind), it may be possible to make Mars easier for humans to live on. Yes it's a big "if", but it's an area scientists are making a lot of progress in, so I wouldn't discount it completely.

However, I'd be more worried about this:
http://science.nasa.gov/science-news/science-at-nasa/2001/ast31jan_1/

If that's true, you'd be fighting a losing battle no matter what you do.

NASA has basically bet the Mars program on the soon to be launched MSL. If it doesn't work, it will be very hard to keep the teams of researchers intact for the very long gap until the next mission.

I predict that planetary (and lunar) exploration will be internationalized under the ISECG's Global Exploration Roadmap, which is the best thought out plan for space exploration I have seen in a long time.

I wonder why the south pole station doesn't make more use of robotic transport such as the Tubleweed Rover, ballistic transport pods or steerable balloons to transport supplies rather than depending on people. The ISS relies on robotic "progress" supply ships at least as much as it relies on human space flights. If we can do this in space, why not on earth?

This page has audio of the Phoenix probe descending through the amosphere

There is an animation of objects moving in the wind

Theoretically, if you had a fast enough light sensor, you could use video capture to record the changing reflections of light on an object due to the Martian wind. Like the old cub-scout science badge experiment of gluing a small piece of mirror to a plastic membrane over a paper cup, then watching the changing reflections of light due to air vibrations.

NASA - Final Minutes of Curiosity's Arrival at Mars

I bet the high res video of the descent will be interesting to watch...

"Skeptics" tend to have difficulty with nuance. (He said it would go up but they say it went down last year... I just don't know WHO to believe!). They also tend not to read original sources but rather like to read spin from sites with unintentionally ironic names.

You have referenced a NASA post that confirm exactly what I noted above (that droughts come with floods), and is exactly consistent with everything Hanson has ever published (regardless of what someone may recall from a conversation that he may have had 20 years ago). Here is what NASA really said: http://www.jpl.nasa.gov/news/news.cfm?release=2011-262

Like mercury in a thermometer, ocean waters expand as they warm. This, along with melting glaciers and ice sheets in Greenland and Antarctica, drives sea levels higher over the long term. For the past 18 years, the U.S./French Jason-1, Jason-2 and Topex/Poseidon spacecraft have been monitoring the gradual rise of the world's ocean in response to global warming.

While the rise of the global ocean has been remarkably steady for most of this time, every once in a while, sea level rise hits a speed bump. This past year, it's been more like a pothole: between last summer and this one, global sea level actually fell by about a quarter of an inch, or half a centimeter.

So what's up with the down seas, and what does it mean? Climate scientist Josh Willis of NASA's Jet Propulsion Laboratory, Pasadena, Calif., says you can blame it on the cycle of El Niño and La Niña in the Pacific.

Willis said that while 2010 began with a sizable El Niño, by year's end, it was replaced by one of the strongest La Niñas in recent memory. This sudden shift in the Pacific changed rainfall patterns all across the globe, bringing massive floods to places like Australia and the Amazon basin, and drought to the southern United States.

Data from the NASA/German Aerospace Center's twin Gravity Recovery and Climate Experiment (Grace) spacecraft provide a clear picture of how this extra rain piled onto the continents in the early parts of 2011. "By detecting where water is on the continents, Grace shows us how water moves around the planet," says Steve Nerem, a sea level scientist at the University of Colorado in Boulder.

So where does all that extra water in Brazil and Australia come from? You guessed it--the ocean. Each year, huge amounts of water are evaporated from the ocean. While most of it falls right back into the ocean as rain, some of it falls over land. "This year, the continents got an extra dose of rain, so much so that global sea levels actually fell over most of the last year," says Carmen Boening, a JPL oceanographer and climate scientist. Boening and colleagues presented these results recently at the annual Grace Science Team Meeting in Austin, Texas.

But for those who might argue that these data show us entering a long-term period of decline in global sea level, Willis cautions that sea level drops such as this one cannot last, and over the long-run, the trend remains solidly up. Water flows downhill, and the extra rain will eventually find its way back to the sea. When it does, global sea level will rise again.

But it won't be a record for long, since the Solar Probe Plus will be heading to a distance of 8.5 solar radii from the surface of the sun a year later. http://science.nasa.gov/missions/solar-probe/

Global warming of about 0.8 deg C over the last 100 years. Mt. Pinatubo's 1991 eruption cooled the earth by 0.6 deg C. Looks to me that one good volcanic eruption can cancel an entire century of global warming. Now add up all the volcanic eruptions we've had in the last century... I think you'll find they affect the climate a lot more than than man-made CO2.

It can cancel it ... for a couple of years. Then of course when the ash and sulfur falls out of the atmosphere, temperatures go right back up. We don't get the biggest volcanic eruption in a century as an annual event.

FFS - does anybody here have reasoning skills beyond a 3rd grade level?

Global warming of about 0.8 deg C over the last 100 years. Mt. Pinatubo's 1991 eruption cooled the earth by 0.6 deg C. Looks to me that one good volcanic eruption can cancel an entire century of global warming. Now add up all the volcanic eruptions we've had in the last century... I think you'll find they affect the climate a lot more than than man-made CO2.

Correction - it was at its smallest in 2007. But this year is a close second.

http://www.nasa.gov/home/hqnews/2011/oct/11-337_Arctic_Sea_Ice_Decline.html

But that is not to say that it couldn't be done, given enough thrust:

Ares martian rocket glider, as presented by Joel Levine.

In this series of shots it looks like Cassini is passing in front of some bright headlights, apparently out of nowhere, or is it just me? http://saturn.jpl.nasa.gov/photos/raw/?start=4&storedQ=2387927

Yes. Link is to a flight test on Earth in as-close-as-we-can-get Mars-like atmospheric/gravitational tradeoff conditions of a prototype Mars aircraft. In fact, that is probably what NASA intends this design to be used for.

Even your own citation said it was growing.

I guess you didn't read it. From my first link:

Meanwhile, measurements from the Grace satellites confirm that Antarctica is losing mass. Isabella Velicogna of JPL and the University of California, Irvine, uses Grace data to weigh the Antarctic ice sheet from space. Her work shows that the ice sheet is not only losing mass, but it is losing mass at an accelerating rate.

I don't claim to be an expert here...

Seriously? You might want to educate yourself instead of spouting off on topics you don't understand.

1. You are referencing an article 9 years old. Things have changed and so has knowledge on the topic at hand.
2. Sea ice extent is not the same as sea ice volume. That's like saying it sure is hot here today - sure proof that climate change is true!
3. First you say we're talking about land-based ice since it's melting will affect sea levels - now you are showing me how sea ice extent is growing? Stick to a topic!

http://www.gsfc.nasa.gov/topstory/20020820southseaice.html

Even your own citation said it was growing.

I don't claim to be an expert here... I just see this stuff in the paper and try to pay attention.

The Antarctic ice sheet certainly isn't growing according to the experts. Not sure where you got that idea.

Is Antarctica Melting?
The Future of the West Antarctic Ice Sheet

I certainly didn't say "scientists" before in this tread because that was my only post (until this one) in the thread. But in general if I say scientists it's in the context of the field being discussed, not every scientist in the world. I guess the GP did use the term "*Some* scientists" but I don't consider those not working the field in question to have much authority to comment on it.

In regards to surface temperature there's a project called Berkeley Earth Surface Temperature lead by the physicist Richard Muller who has expressed some skepticism of global warming that is examining that right now. They still have a long way to go for their final report but the initial findings don't do anything to discredit the current science.

A preliminary analysis of 2% of the Berkeley Earth dataset shows a global temperature trend that goes up and down with global cycles, and does so broadly in sync with the temperature records from other groups such as NOAA, NASA, and Hadley CRU. However, the preliminary analysis includes only a very small subset (2%) of randomly chosen data, and does not include any method for correcting for biases such as the urban heat island effect, the time of observation, or other potentially influential biases.

I left the second sentence in because I acknowledge they have much work to do yet but I will be surprised if their results don't largely validate the current science.

Throw out all of the proxy data and it doesn't matter that much. It's merely corroborating evidence. What matters is the science that's being done today on today's climate.

Economics don't matter until you decide what to do about it which is a political question. It doesn't change the science one bit.

The CRU's paleoclimate temperature estimate code is not a computer model. It is code to process a large dataset. Code for several of the major GCM's such as NASA/GISS Model E are available so feel free to analyze them yourself. Not sure what you're getting at with that last sentence.

The only thing that isn't reproducible in climate science is the data about what happened in the past. It's easy enough to redo the research that determined the effects of different factors on the climate. It's true that it isn't particularly amenable to much lab experimentation but even that occurs (the CERN CLOUD project).

I largely agree with your third point.

I think you see bias because the findings don't say what you want to hear. Someone's going to have to make a much more solid case on that before I'll take the accusation seriously.

An argument from authority isn't necessarily wrong.

The strength of this argument depends upon two factors:

        The authority is a legitimate expert on the subject.
        A consensus exists among legitimate experts on the matter under discussion.

I would argue that climatologists are indeed legitimate experts on the subject and the study I cited demonstrates there is a consensus in the field. Therefore it is not a fallacious appeal to authority.

You do know that the 1980s were 30 years ago, right? In fact, since the Shuttle R&D started in the 1970s (and of course earlier, using prior designs as departure), it's over 30 years. You do realize that all NASA spaceflight is R&D work, right? People at SpaceX surely know that.

How did it match the money poured into it? Even ignoring the tremendous return on investment from NASA budgets, anyone honest at SpaceX would tell you the new private industry owes a vast debt to NASA's programmes. That it can repay naturally in taxes from its profitable operations.

Pictures would be nice

Actually I was lead to believe that is exactly how they do it, they do multiple runs with slightly twiddled parameter to exclude chaotic effects. Some parameters are hard-coded and some are configurable, and the source codes are hideous pile of spaghetti written by an endless stream of students with highly variable programming skills and software engineering skills. Because the code are often so poorly written, changes and updates can easily have unintended side-effects in other sections of code, and there are almost certainly areas where the researchers think a parameter is configurable and is hard coded in another subroutine. You can download code for modelE at NASA, considerable effort is being put into bring this model up to modern software standards.

The Russians deployed the Znamya space mirror from a Progress resupply ship in 1993, and tried a second time in 1999. The Progress propelled and steered it to reflect a spot of light down on the Earth, so it didn't do actual solar sailing. IKAROS has that distinction. This new mission will actually test a 38m x 38m sail, so it will be the largest.

The key advantage is that the propulsion system doesn't run out of fuel.

Perhaps; but that doesn't change the fact that it still costs a lot of money and fuel to break free of the gravity well.

Putting the cart before the horse, if you ask me.

The key advantage is that the propulsion system doesn't run out of fuel.

Perhaps; but that doesn't change the fact that it still costs a lot of money and fuel to break free of the gravity well.

Putting the cart before the horse, if you ask me.

The Gizmag article was... imprecise. The sail will be a square 38m wide, with an area about 1400 m^2. It's based on a 20m wide sail L'Garde built and tested for NASA in 2005. More info here: http://www.nasa.gov/offices/oct/crosscutting_capability/tech_demo_missions.html

NASA has an entire program office dedicated to tracking tens of thousands of pieces of orbital debris as small as 1cm: http://orbitaldebris.jsc.nasa.gov/measure/radar.html

NORAD has a network of satellites and radar stations dedicated to finding incoming threats.

But somehow, despite all this capability and despite tracking the descent of a 5,900 kilogram multi-meter by multi-meter satellite, they don't know where it hit.

?!?

We've had Jupiter sweeping out the solar system for billions of years; the extinction-level event that you are referring to occurred 65M years ago,

65M years is not very long in geological terms. In fact, that's less that 2% of the planet's age.

and there are no impact events even remotely on that scale since.

There's been impacts all over the world, with craters to prove it. I live a 4-hour drive from one of them, located in northern Arizona; watch the movie "Starman" and you can see it. It's relatively recent, as it's so well preserved (unlike the Chicxulub crater which is pretty hard to see now, except for the geological evidence around its rim); Wikipedia says it's only 50,000 years old. And only 103 years ago, an asteroid struck Tunguska, Siberia with the force of 5-30 megatons of TNT, about 1000 times more powerful than the Hiroshima bomb.

Here's a whole list of impact craters:
http://en.wikipedia.org/wiki/List_of_impact_craters_on_Earth
but this list only shows the largest ones (with a rather large one being only 5 million years old); the smaller ones like Meteor Crater are on regional pages, and there's quite a lot.

The fact that we have nuclear-bomb-size asteroids hitting our planet within the century should be worrying. Sure, the damage will be minimal if it hits Siberia again, or an ocean, but there's a lot more people on the planet now than there were even just a century ago, and the havoc that would ensue if a Tunguska event happened in any major city like London, Washington DC, or Beijing, would cause serious repercussions worldwide, not to mention the millions of dead. There's dozens of known objects with a risk of hitting the earth. You can see the list here: http://neo.jpl.nasa.gov/risk/
99942 Apophis is projected to come so close in 2029 that it will be under the orbit of our geostationary satellites. What if NASA is wrong, and some gravitational perturbation has a bigger effect than they calculated, and this puts it on a collision coarse with the planet? Worse, it's projected to swing around again for another fly-by, and "It is not currently possible to accurately predict the path of Apophis subsequent to the 2029 encounter because its present orbit is not yet known to a sufficiently high precision — very small differences prior to the planetary encounter can produce large differences in orbit after the encounter." So it's very possible it could collide with earth in 2036. If it does hit, it's projected to have an impact energy of 510 megatons, 10 times the power of the largest nuclear bomb ever exploded. That wouldn't be a planet-killer of course, but it would still be devastating. Some people are predicting it might strike Columbia and Venezuela, where it could have more than 10 million casualties. It could also strike in the Atlantic or Pacific oceans, causing a massive tsunami, which could kill even more since so many people live on the coasts.

You think that's not worth developing an asteroid deflection strategy?

IMO the goal of our space programs isn't just to put humans into space. It also serves to dump piles of money into US science an tech development. Our space program is an investment in the US that allows us to maintain a technological edge. We've lost hope of outproducing developing countries like China, out best chance now is to keep ourselves ahead of them technologically. We can't do that unless we are keeping our scientists and engineers working and advancing our sci/tech industry.

Not a lot of people realize this, but spending in technological research has actually been a fairly small portion of NASA's budget for quite some time, with far more money going towards things like paying for the standing army of maintenance personnel for the Space Shuttle.

In the past few years NASA asked for permission to spend $1 billion/year to revive technological research in NASA and invest in technologies needed to perform new types of exploration missions and perform existing missions more cost-effectively. Unfortunately, Congress wasn't a fan of the idea, IMHO because they weren't sure if the money would end up in the districts of Congresspeople who typically support the NASA budet. Instead, Congress diverted almost all the space technology money to building the SLS, an in-house rocket based on Shuttle-legacy technology. The two main features which have been politically touted for the SLS have been that it employees a large number of former Shuttle contractors and minimizes development of new technology.

The solution is for Congress to allow NASA to invest in research in space technology again, but it'll probably be a while before that happens.

Yup. Even if one minute is SOLELY the "loop the loop" part, not the big fall or the climb, it wouldn't be enough to kill you.

According to NASA, testers survived 17 Gs for "several minutes" without serious long-term harm. One minute at 10 Gs isn't going to do it.

Source: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19980223621_1998381731.pdf

NASA report contradicts publicity seeking artist

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19980223621_1998381731.pdf ...and how surprising is that, really.

-- Terry