New Horizons: One Billion Miles From Pluto 135
astroengine writes "On Feb. 10, NASA's Pluto-bound New Horizons probe entered the homestretch of its mission. When you are sprinting across the solar system, 'homestretch' is the final 1 billion miles of your journey. That sounds like quite a long stretch! But the half-ton spacecraft has already logged 2 billion miles since its launch in early 2006. That's twice the distance between Earth and Saturn. Though the icy dwarf planet is still three years away from its close encounter, mission scientists call this the Late Cruise phase of the flight."
Astronomical distances and poetry (Score:2, Interesting)
Whenever I see posts like this, it always makes me think about how big the universe really is. Poets have talked about how far away the stars are and planets and the like. They always talked about hundreds or thousands of miles. Then we get to the real size of the universe and BAM! all of that is now wrong. Even modern poets usually talk in terms of "millions" of miles or kilometers to reach the stars and planets. Makes you seem really small when farther than you can even imagine is not far enough.
The Vertically Challenged Planet (Score:5, Interesting)
Getting to pass close to an object as small as Pluto, (reclassified as I like to say as a "vertically challenged" planet) from 3 billion miles away is impressive. Especially since this is no sitting duck.
This is an object whose velocity is measured in KM per second moving in a very eccentric orbit.
We often take for granted NASA does this and NASA does that- because they have been doing it for decades- but it never ceases to amaze me how we can so accurately target (relatively) small objects that are travelling at such incredible speeds from such mind boggling distances.
9.98 AU from Pluto (Score:5, Interesting)
Distance from Earth (AU): 23.06
Distance from Pluto (AU): 9.98
IMHO much more sense than billions of miles.
Think about this (Score:4, Interesting)
If it had not been for the exhorbitant cost of the wars, we could have afforded to build a probe to orbit Pluto rather than just do a flyby.
As it was, New Horizons was largely made possible by a few congressman who pushed specifically for funding for this mission before Pluto's orbit [windows2universe.org] removed it too far away from the sun.
Re:You are here (Score:4, Interesting)
I feel like the image titled 'pale blue dot' does a better job of illustrating just how... small we are in the grand scheme of things.
http://upload.wikimedia.org/wikipedia/commons/7/73/Pale_Blue_Dot.png [wikimedia.org]
Do a search on youtube for 'Pale Blue Dot' by carl sagan if you want to be humbled.
Re:I'm impressed, (Score:5, Interesting)
FWIW, I think most folks are just thinking about things wrong when they talk about velocity of space vehicles. It's often better to think of things in terms of work and kinetic energy (force x distance). For example, interestingly, once you are in geosync** orbit***, the "escape" speed (aka escape velocity) is even lower than on the ground (since escape_speed ~ sqrt(2GM/r), bigger "r" means lower escape speed), but moving a certain distance and having a certain kinetic energy in the gravitational potential well are more intuitive notions.
Besides, velocity is "generally" relative anyhow ;^) Acceleration is the interesting notion. Standing on earth we are already all going 65,000mph relative to the sun because the earth is in orbit (meaning the earth is balanced between falling into the sun and flinging away). It's only the difficulty of maintaining a chosen velocity on earth where there's lots of friction that warps our perception of velocity. Under constant acceleration in a vaccuum, acheiving high velocity is just a matter of waiting for some time.
**Geosync is just the orbit you have to get to so that the gravitational acceleration matches the centripital acceleration needed to maintain the same relative position on the ground. Of course for a satellite still on the ground, that's easy, static frictional forces provide the needed acceleration to maintain the same relative position on the ground. When the satellite is launched above the ground, there aren't any static frictional forces, so you need to rely on gravity to apply the appropriate gravitational acceleration. If mass and the gravitational constant are invarient, you really only have the radius to play with. You then get whatever "circular" velocity you get at that radius (or you don't stay in orbit very long) w/o applying additional forces over the gravitational force.
***In orbit, you sweep out equal areas in equal time, so in a highly eccentric orbit (or even a parabolic or hyperbolic orbit that you get with gravity assist), you can get really, really, high velocities at some points in the orbit. Of course these types of orbits aren't geosync orbits anymore.
Re:Astronomical distances and poetry (Score:5, Interesting)
Re:Astronomical distances and poetry (Score:4, Interesting)
From the second Wikipedia link [wikipedia.org] in your post:
"If the universe is finite but unbounded, it is also possible that the universe is smaller than the observable universe. In this case, what we take to be very distant galaxies may actually be duplicate images of nearby galaxies, formed by light that has circumnavigated the universe."
Mind blown.