Saturday, December 13, 2008

Another ice storm--oh no!

A few years back, when we lived in Vermont, we endured an ice storm. We had no electricity for about 5 days. That house had a wood stove, so we could cook and keep the house warm. The main problems were related to water: We had well-water, so no water pressure for the duration and we had water leaking into the basement with no power for the sump-pumps.

This time we faced different problems. We have city water and the hot water heater is gas, so we have hot & cold running water. The basement is dry and we don't even own a sump-pump. The only way to heat the house is by the gas range (which works, but you have to light it manually) and the fireplace (which doesn't help much for the whole house, but makes that one room very nice).

My wife stayed home with the kids on Friday and she took a bunch of pictures which I will post once we have power back.


Sunday 6:00 PM--still no power. Houses which are tantalizingly close, do have power. I have seen hardly any utility crews, but they are out there making progress.

Update 2:

Tuesday morning--Still no power. The morning news said there are still around 70,000homes and businesses without power. This is down from the more than 200,000 in our state without power at the end of the storm. So they have fixed 2/3 of the problem and all resources are concentrated in 1/3 of the original area.

Friday, December 12, 2008

High speed approach technique

I have flown a lot over the years and I have noticed that pilots do not all handle the final bit of a flight in the same way.

What it seems like some do is they cruise at altitude until pretty close to the end and then they throttle-back and let the plane loose altitude as they approach the destination airport.

Other pilots start their descent from further out. They keep the engines on roughly cruising power (based on the sound) and the descent is more gradual in terms of lost altitude (based on ear-pressure) and the air-speed is kept high.

To me, the second method seems better. They are using altitude gained at great expense in the start of the trip to get something back: Speed at the end of the trip.

It could be deceptive though. The sound of the wind rushing past the fuselage makes me think we are going faster on the high speed descent. But the air is thicker as you descend, so that could be the source of the added sound. It is easy to think of ways of testing which method is superior: Just set the engines to burn at the same rate and fly both profiles. If they use the same fuel, but one gets there faster, then it is a better method.

I haven't kept good (or any) records, but anecdotaly it seems as if the high speed approach is used more when the flight is running late and the slow approach when the flight is ahead of schedule.


You cannot exceed C, but you can feel like you are...

Actually you can't even do that.

The technology is a long, long way off to be able to accelerate at one G for more than a few minutes. Let's just say though that in the distant future there will be energy sources sufficient to accelerate at one G for months at a time.

If you could maintain this kind of acceleration for around one year, you would be going around 99% of the speed of light.

If you were going on a journey of 20 light-years' distance, in the first year you would cover about 0.5 light-years. Due to Lorentz contraction, over the period of acceleration, the distance will appear to shrink to only one tenth the original distance. So, the destination will now appear to be only 1.95 light years away.

If the destination looked 20 light years away at the start of the trip, but only looks 1.95 after one year, then it will appear to the passengers on this ship that they have covered some 18 light years in one year. Actually, less than a year for them since by the end of it, time will be moving only one tenth as fast as at the beginning.

It would all be spoiled if they looked back at their starting point: That 1/2 light year will have also contracted to 1/20th of a light year and so it will seem to them that they are making woefully slow progress getting away from the starting point.

What would be really odd is if they decided to decelerate over the course of the next year: The whole time they would be moving toward the destination and yet it would look as if it went from 1.95 LY distant to 19 LY distant over the one year period. The starting point too would go from looking .05 LY to 1.0 LY. Both would appear to be getting more distant! Odd stuff.

Sunday, December 07, 2008

Why not see how far you can go too.

This profile is like that of Virgin Galactic's: It just goes up and then glides down back to the starting point. My bet is that more people would pay for the experience if they could go from L.A to N.Y.C. in 40 minutes, in addition to all the going into space stuff.