Other Than Mars Thread

Quote: rxwine

If a probe can reach Alpha Centauri in 20 years, why haven't we launched one already? I mean unmanned of course. Is there some technology still lacking?

4.367 light years away sounds close enough, and now Stephen Hawkings and others suggest means of attaining speeds no one thought possible. The article in the link says "regular spacecraft would take more than 30,000 years" ... now the idea is to use tiny nanocraft and propel them by an untested 'really out there' means.

It is much harder to attain speeds at any kind of considerable fraction of the speed of light than is generally appreciated. Voyager I escaped at about 20 km per second. Speed of light, 299792 km/sec, so for that vehicle it is about 0.0067% percent of the s.o.l. And that speed was only attainable by use of the gravity of Jupiter and other objects, not as much by rocket power.

They are getting pretty clever with this 'slingshot business', in the case of Cassini I saw that not one but two boosts were obtained by the gravity of Venus to start it off!

PS, as for manned missions, if ever the rocket power was developed to get to a fraction of the s.o.l. , they say the astronauts would not be able to take the G's like that over the necessary period of weeks or whatever. G forces can be really high for short periods, but even small such like 2-3 G's over time is torture. Edit: if a rocket engine could be gentle enough to keep it at one G or so, and could keep going for about 4 months like that* to get to about a third of the s.o.l., would that be a solution? Sounds like a lot of fuel, plus there is an effect of needing more and more fuel as you get closer to the s.o. l.

Conventional means seem 'out' ... the things imagined in science fiction are the only hope for manned missions?

*assuming I did that right, using 15 miles per hour per second, which should be a bit more than one G

http://www.iflscience.com/space/stephen-hawking-reveals-plan-send-spacecraft-alpha-centauri-20-years/

Quote: rxwine

If a probe can reach Alpha Centauri in 20 years, why haven't we launched one already? I mean unmanned of course. Is there some technology still lacking?

No probe launched with today's technology could reach the Centauri system in 20 years, probably not even 20,000. If we could put a probe around Alpha Centauri in 20 years, we could get to Mars in days and the Moon in hours.

There's a proposal to launch a few million nano-probes, each no bigger than a microchip, using light sails propelled by ground based lasers. The propulsion is sound, in theory. it hasn't been tried much in practice. so there'd be engineering issues still to be worked out. the lasers would have to be built and powered. Lastly, "everything costs more and takes longer."

Not to mention the nano probes, would merely do a fly-by. There's not enough light energy available at Centauri, even with three suns, to slow them down.

This doesn't mean they're not worth building and launching. But be aware of the limitations.

Was watching a 60 minute episode on the two Voyagers.

They had to rush to get the launches on time, as there was an alignment of several planets that would not occur again for 176 years.

The power of the device still sending signals to Earth some 9 billion miles, is using less power than a refrigerator lightbulb.

And perhaps the most mind blowing one -- one or both of Voyagers could still be traveling through the Milky Way, even after our Sun has died, and Earth is long dead (or possibly consumed by the Sun's previous expansion)

Quote: rxwine

And perhaps the most mind blowing one -- one or both of Voyagers could still be traveling through the Milky Way, even after our Sun has died, and Earth is long dead (or possibly consumed by the Sun's previous expansion)

There's very little friction in space, therefore the Voyagers(*) will continue to move until the universe itself ends, or until they crash into something big enough to stop them.

It's also possible they may be captured by a star at some point. In that case they'd stop travelling, but they'd keep orbiting said star indefinitely.

(*) The same goes for Pioneers X and XI, and New Horizons.

May 8, Jupiter will be in the best position to be seen from Earth. The Sun aligns with it, and it's 5 million miles closer than last year.

8:30-pm 9 ET in the East Southeast sky.

I might even be able to see the red spot with my 8x magnification phone according to some.

How about the moons of Jupiter? I can easily make those out with my telescope here in Vegas. That and the rings of Saturn are about the only things I know to look at. Everything else just looks like a dot in the sky.

Quote: rxwine

If a probe can reach Alpha Centauri in 20 years, why haven't we launched one already? I mean unmanned of course. Is there some technology still lacking?

As of January 2018, Voyager 1 (launched September 5, 1977), the farthest man-made object from Earth, is 141.5 AU away where AU=average distance from Earth to the Sun. So Voyager 1 is averaging less 4 AU per year.

The closest known star Proxima Centauri, however, is some 268,332 AU away.

Most estimates of even being able to launch a micro probe to another star means that it won't launch for another century and may take several centuries to get to the destination.

I had a small epiphany the other day, when I came across a solution to something I had been thinking about. It turned out I was not asking the right question.

Which leads me to wonder if some of these seemingly unsolvable problems could be due to asking the wrong questions.

For instance the question may not be how to travel to other stars in interstellar space, but the questions should have always been how to figure out everything from here. If you want to lift the rock that can't be lifted to find out what's under it, in fact, you may want to focus on something other than lifting it.

Quote: rxwine

I had a small epiphany the other day, when I came across a solution to something I had been thinking about. It turned out I was not asking the right question.

Which leads me to wonder if some of these seemingly unsolvable problems could be due to asking the wrong questions.

For instance the question may not be how to travel to other stars in interstellar space, but the questions should have always been how to figure out everything from here. If you want to lift the rock that can't be lifted to find out what's under it, in fact, you may want to focus on something other than lifting it.

I really like that insight.

Quote: rxwine

For instance the question may not be how to travel to other stars in interstellar space, but the questions should have always been how to figure out everything from here. If you want to lift the rock that can't be lifted to find out what's under it, in fact, you may want to focus on something other than lifting it.

My boss used to say if you don't know the answer to a question, then change the topic of conversation.

So if we can't figure out how to feed the starving billions, we could figure out how to humanely sterilize them so we could get a population we could feed.

If we will never figure out how to build enough freeways, train tracks and airports, we should focus on virtual meetings and virtual travel. What we really need is an internet that can transmit holography.