After almost ten years of diligent observations of the earliest light in the universe, the Wilkinson Microwave Anisotropy Probe (WMAP) fired its thrusters on September 8, and entered the world’s longest and most tedious holding pattern, circling the sun in a so-called graveyard orbit.
WMAP has been a triumph of observational cosmology. It has strengthened the case for cosmic acceleration, one of nature’s most mysterious phenomena; measured the composition of the universe, teaching us about dark matter and dark energy; observed the polarization signal, telling us about reionization; provided results consistent with an inflationary origin for the universe, while constraining and even ruling out some of the simplest models; and has left us with some intriguing open questions of its own. To those of us in the field, it seems like only yesterday that we were eagerly awaiting the first 3-year data release from WMAP. Now, the final data, collected on August 20, will form part of the complete 9-year dataset, capping a remarkable decade of cosmic discovery.
From a fundamental physics perspective, WMAP is a crucial component of increasingly accurate cosmological observations that challenge the standard model of particle physics. In accurately determining the dark matter abundance, it has specified even more precisely the requirements of the new particle physics required to account for that portion of the energy budget. If dark matter is made of Weakly Interacting Massive Particles (WIMPs), for example, the range of properties they might have is more tightly constrained. In supporting the case for cosmic acceleration, it has sharpened the need for a fundamental explanation for the size of the cosmological constant and possibly for entirely new physics, such as dark energy or a modification of General Relativity. In providing a measurement of the baryon content of the universe in agreement with that required for successful primordial nucleosynthesis, it has further underscored the need for an explanation for the matter-antimatter asymmetry of the universe, some proposals for which will be tested at the Large Hadron Collider (LHC). And in its precise measurements of the spectral index of the temperature fluctuations, it has constrained existing and newly-proposed models for the physics of the very early universe, requiring an almost scale-invariant spectrum, with specific small deviations.
We’re going to miss WMAP, but we’re not standing still – cosmologists are a very forward looking bunch for people whose lives revolve around what happened so far in the past. A host of new projects are coming, and in the microwave field the big one is the Planck satellite, already taking eagerly awaited data. So goodbye WMAP, and thanks! Now, what’s next? We’re hungry for more information!
October 8th, 2010 at 8:10 am
[...] This post was mentioned on Twitter by mjd402, Al Poe, Maggie, Sains & Teknologi, World Amazing Things and others. World Amazing Things said: Bye Bye WMAP | Cosmic Variance: After almost ten years of diligent observations of the earliest light in the unive… http://bit.ly/cdGWvr [...]
October 8th, 2010 at 8:11 am
[...] at Cosmic Variance has just reminded me that I was expecting the end of WMAP. Read what he says [...]
October 8th, 2010 at 9:20 am
Clearly a “graveyard orbit” is better than leaving it as space junk in a normal orbit. But why not go further and de-orbit it entirely? Not enough fuel?
October 8th, 2010 at 10:04 am
Deorbiting a satellite from L2 would require quite a lot of fuel. Remember, L2 is around six times as far from the Earth as the moon!
I am curious as to exactly what orbit it’s going to take now. As I understand it, L2 is an unstable Lagrange point, meaning that even a tiny thrust in one direction or another will cause it to go far out of L2. But which way did it thrust? Where is it going?
October 8th, 2010 at 11:33 am
WMAP will orbit the sun out beyond L2. They just gave it a push and it slid of the gravity saddle at L2, and that was that.
A complete de-orbit was very doable. Lots of fuel left. But no one wanted to spend the money to smash it into the moon (more water studies at the poles), or bring it down to low earth orbit to pick it up with a shuttle for study of L2 environment effects.
October 8th, 2010 at 1:41 pm
So. Farewell then little probe.
For your long service we commend you
and send you
to infinity
and beyond.
- E. J. Thribb (17½)
October 8th, 2010 at 2:07 pm
[...] en Herschel. WMAP, het gaat je goed in die grafbaan en bedankt voor al je werk! :bron: Bron: Cosmic Variance.Gerelateerde Astroblog:Resultaten van vijf jaar WMAP zijn bekendTags: donkere energie, donkere [...]
October 13th, 2010 at 4:52 am
[...] Bye Bye WMAP (blogs.discovermagazine.com) [...]
October 21st, 2010 at 6:49 pm
I rather prefer the solar orbit to earth- or moon-based destruction. It means in a few decades or hundreds of years when we have the technology, we can go there, pick them up and return them to a museum on Earth.
Alternately if we should fail to develop the technology or wipe ourselves out for one of any number of reasons, the spacecraft will still be there in a few million years for aliens to find and learn our capabilities and wonder who we were and what happened to us.
October 25th, 2010 at 6:32 am
[...] of observatories in space. In five years most, if not all, of these telescopes will be defunct (WMAP is already in the graveyard), and it’s not clear what will be replacing them. This is brought into startling focus by the [...]
November 4th, 2010 at 12:54 pm
[...] 9 Messjahre geben wird; die ersten 7 sind bereits verarbeitet. (NASA Release, Spaceflight Now 6., Cosmic Variance 8., Space Today 10., Nature [...]