Mars Images Reveal Evidence of Ancient Lakes 128
Matt_dk writes "Spectacular satellite images suggest that Mars was warm enough to sustain lakes three billion years ago, a period that was previously thought to be too cold and arid to sustain water on the surface, according to research published today in the journal Geology. Earlier research had suggested that Mars had a warm and wet early history but that between 4 billion and 3.8 billion years ago, before the Hesperian Epoch, the planet lost most of its atmosphere and became cold and dry. In the new study, the researchers analysed detailed images from NASA’s Mars Reconnaissance Orbiter, which is currently circling the red planet, and concluded that there were later episodes where Mars experienced warm and wet periods."
Re:We'll Never Know For Sure (Score:4, Interesting)
Re:How do they determine those dates? (Score:3, Interesting)
As a Canadian, I have to quirk my eyebrow at that.
You realize that we have supplementary coverage up here, right? Hear me out.
The government provides basic health coverage. They cover almost everything, from emergency treatment to birth and annual physicals.
We don't get coverage for private rooms, eyeglasses, Rx medication (unless you spend $3k a year or more, long story), massage, physio, etc. There's a long laundry list of things that aren't covered. Ambulance rides aren't covered, but that's because too many people were using it as a taxi service. It's $65, but when you need one, it's money well spent.
I can go out and buy more coverage. My wife gets Green Shield from work, and that covers $250 in eyeglasses every 2 years, massage and physio, 80% reimbursment on medication, private rooms, dental care, etc. I have an HSA at work, but I use my wife's plan instead because it's a better plan.
When my kids were born, it cost me $12 for parking each time. When they got hit by a car and rushed to the hospital, it cost me $10 for dinner and $65 for the ambulance. (For each of the above, there were multiple ultrasounds, xrays, blood tests, beds, bandages, etc.) That's all I had to pay.
When it's critical, there aren't wait times, despite what you may have heard. My friend had a sharp pain in his head when he coughed -- he was ushered in right away, had an ultrasound, a CT scan, and a spinal tap within 30 minutes of arriving at the hospital. (The wait was because someone was in the machine.)
I was having chest pains about six months ago, so I went to a drop-in clinic (not my regular GP) and had an ECG within about 15 minutes.
This is all stuff that's just covered up here, and always has been. True, the system has faults, but that's because our politicians up here get really good secondary coverage so they don't feel any pain from cutting back on health care spending. (These are the same breed of jokers that brought Canada from the 3rd largest Navy in the world at the end of WW2 to the 3rd-div team it is today.) If they increased health-care funding, we'd be in much better shape and the Americans would have nothing to point their fingers at.
By the way, my tax rate was ~15% in 2008. I haven't done my 2009 taxes yet. (It's not a directly fair comparison because we also have subsidized education up here -- my engineering degree cost me ~$0 net.)
Re:Terraforming? (Score:1, Interesting)
No, you're not missing anything. The "not enough gravity" explanation is completely bogus. Titan is a lot smaller than Mars, hell it's only half as massive as Mercury, and holds on to an atmosphere with a surface pressure 50% greater than earth. In fact, the atmosphere is so thick and the gravity so low, that a human could strap on a pair of wings and easily flap their way to self-powered flight.
The real culprit behind Mars' lack of atmosphere is twofold.
1. no magnetific field
2. the sun
The Solar wind is not being defelected by a magnetic field, so it's slowly been stripping away the atmosphere for a couple billion years, a little bit at a time.
With some localized global warming, there may be enough water ice trapped under Mars' surface to start chainreaction greenhouse effect. Get some Water Vapor and C02 into the atmosphere, warm up the planet a few degrees, get some more melting/released from under rocks, until it's all up there and we've got a workable atmosphere around the planet. As another poster pointed out, you DO eventually lose that atmosphere for the same reason Mars lost it's original atmosphere, and you won't be able to replace it the same way as you've already used up that resource... BUT, you don't have to use the same method. I'd think that with a couple million years (realistically, more like a couple hundred years at the rate our technology advances), Human beings would have figured out how to manipulate asteroids and comets on a molecular level, and be diverting some asteroid belt and kuiper belt objects towards mars to replenish the atmosphere from time to time.