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Mission Complete! WMAP In 'Graveyard Orbit'
astroengine writes "The Wilkinson Microwave Anisotropy Probe (WMAP) has, quite literally, changed our view of the Universe. And after nine years of mapping the slight temperature variations in the cosmic microwave background (CMB) radiation, its job is done and NASA has commanded the probe to fire itself into a 'graveyard orbit' around the sun. WMAP measured the most precise age of the universe (13.75 billion years), discovered more evidence supporting dark energy and dark matter theories, and found one or two mysteries along the way."
It would actually require a lot of delta-v; you need less to get to other stars (time of travel being what limits us in this case)
One that hath name thou can not otter
They could just as well send it plunging to burn up in Earth's atmosphere. It actually takes more energy to send it on a safe Earth-bound trajectory, and a lot more to send it on a sun-bound trajectory, than it does to move to a graveyard orbit higher up. That way they can keep running the satellite until it's fuel tank is closer to empty.
So Dark Matter was a theory invented to explain why stars orbit a galaxy's core like they were on spokes around the hub of a wheel ...instead of how we observe the motion of object orbiting our sun. So if Dark Matter exerts such a huge force to keep huge objects (stars) moving in such a manner, how come that same force doesn't affect the objects going around the star? Or, in other words, if it's powerful enough to keep the outer-most stars in a galaxy moving in the same period as inner stars, how come we can't detect it here? Or have we detected such tidal forces already?
While there's a lot of dark matter in a galaxy compared to "normal" matter, it's typically spread out over a much larger volume than the viewable parts of a galaxy. Thus, it is actually quite diffuse and has very little effect within something on the scale of a solar system (to the point of being unmeasurable with current technology).
Probably on the off-chance that it discovers something while in a graveyard orbit. You never know what sort of crazy stuff happens when you just leave a camera running. Sure, the odds are pretty low, but the satellite's already in space, so why not?
If there's some clumsy PR, it seems to be in other part of TFS. WMAP has not ,"quite literally, changed our view of the Universe" - it further refined it nicely, continuing in the footsteps (if mentioning only large space experiments) of COBE and RELIKT-1 (the latter might be one sad example of another type of clumsy PR - apparently already gave us large part of the results for which COBE is praised, but...)
One that hath name thou can not otter
The dark matter halo around our galaxy is theorized roughly as a large sphere, not just extra mass along the flattened wheel of the spiral. Look at the graphic here: http://startswithabang.com/?p=656
That's a lot of extra room. So much so that even when those researchers calculated that our solar system should have 300 times the dark matter density compared to the galactic dark matter halo, this only ends up being a very tiny fraction of the earth's mass in dark matter bound to our solar system. See: http://www.universetoday.com/15266/dark-matter-is-denser-in-the-solar-system/
So basically, it's going to be rather difficult to detect dark matter nearby.
What if the cosmic background "warmth" which hovers just above 2 Kelvin isn't the remnants of the Big Bang but rather a physical phenomenon produced by some more general
What you need to understand is that what you said, while sounding philosophical to the uneducated is gibberish. To a scientist what you said sounds something like "What if what I thought was my hand was actually an ardvaark in disguise". There are specific properties/features of the CMB that require it to be left over radiation from the Big Bang. Of course to understand this you also need to understand the Big Bang itself and why we'd collectively believe something so counter-intuitive as the universe beginning from a singularity. In other words you need to read your science historyf or the last couple of hundred years.
These posts express my own personal views, not those of my employer
..... and thanks.
The prior orbit was at the L2 point http://en.wikipedia.org/wiki/Lagrangian_point#L2 one of the very few stable points in the solar system. Leaving WMAP there would be a bad idea because it makes a very nice spot become more hazardous. We're already having serious trouble with spacejunk in Earth orbit. There's no good reason to star trashing up the rest of the system also.
Yes, we're waiting for it to become a zombie, and then start killing satellites that are still working, turning them into zombies as well...
Sleep your way to a whiter smile...date a dentist!
I guess no one knows such things, but I wonder what would prevent it from clumping up like normal baryonic matter. Maybe it's too diffuse to form dark matter nebulae, but those are only held together by gravity too, right? Or would fast-moving particles just fly apart before gravity could act? Or maybe we just can't see the clumps. Or maybe it's a happy medium—loosely bound to the galaxy but nothing more...
Actually, the explanation for this one is pretty simple: it's because the dark matter is dark. The reason why baryonic matter collapses into a (relatively) tiny disk in the center of a much larger dark matter halo is that baryonic matter emits light... and light carries off energy. So baryonic matter quickly loses all the energy it can while still conserving angular momentum, and the result is a disk-like structure (spiral galaxies). Once it collapses into a disk, the density becomes high enough that it can further clump into nebulae and stars and such. Dark matter, on the other hand, is much lower density and hence isn't able to collapse efficiently (i.e. its Jean's Length is much longer, if you want to think in terms of some simple math).
Silly Christian propaganda! Islam provides a far more accurate view of the heavens than any man-made space doohickey . I bet Muhammed (Geese be upon him) got a pretty good look at space while he was traveling around on his flying mutant horsie, hobnobbing with all and sundry in heaven.
Hmm, come to think of it I think there may have been some man/horse love - at least if this excerpt is anything to go by:
"Hearing this he (the mutant horsie) was so ashamed that he sweated until he became soaked, and he stood still so that the Prophet mounted him."
-- Using the preview button since 2005
The orbit was *around* L2, not at L2. The orbit around L2 appears as loops with an apreciable extension wrt to the Earth-L2 distance.
The paradox is that L2 is actually unstable, but orbits can be found around L2 which are stable over a sufficiently long time.
I concur, and a favorite comic springs to mind:
Science: It works, bitches
From the wikipedia page about the CMB:
Two of the greatest successes of the big bang theory are its prediction of its almost perfect black body spectrum and its detailed prediction of the anisotropies in the cosmic microwave background.
When basically the whole observable universe matches your theory, it's generally considered pretty strong evidence that you're going in the right direction.
You are in a twisty maze of processor lines, all alike.
There is a lot of hype here.