Chancewu's Singular particles

版权声明：转载时请以超链接形式标明文章原始出处和作者信息及本声明
http://chancewu.blogbus.com/logs/37543644.html

分享个搞怪的Rap...其实也不"怪"

国内有九维空间兄的<退相干><爱在量子力学前>国外的也有不少哈 这不咱最近听到了首关于Dark Matter的Rap抓过来共享下

歌词如下：

The Dark Matter Rap: Cosmological History for the MTV Generation

My name is Fritz Zwicky,
I can be kind of prickly,
This song had better start
by giving me priority.
Whatever anybody says,
I said in 1933.
Observe the Coma cluster,
the redshifts of the galaxies
imply some big velocities.
They're moving so fast,
there must be missing mass!
Dark matter.

Dark matter: Do we need it? What is it? Where is it? How much?
Do we need it? Do we need it? Do we need it? Do we need it?

For nearly forty years,
the dark matter problems sits.
Nobody gets worried 'cause, "It's only crazy Fritz."
The next step's not 'til the early 1970s,
Ostriker and Peebles,
dynamics of the galaxies,
cold disk instabilities.
They say: "If the mass, were sitting in the stars,
all those pretty spirals, ought to be bars!
Self-gravitating disks? Uh-uh, oh no.
What those spirals need is a massive halo.
And hey, look over here, check out these observations,
Vera Rubin's optical curves of rotation,
they can provide our needed confirmation:
Those curves aren't falling, they're FLAT!
Dark matter's where it's AT!

Dark matter: Do we need it? What is it? Where is it? How much?
What is it? What is it? What is it? What is it?

And so the call goes out for the dark matter candidates:
black holes, snowballs, gas clouds, low mass stars, or planets.
But we quickly hit a snag because galaxy formation
requires too much structure in the background radiation
if there's only baryons and adiabatic fluctuations.
The Russians have an answer: "We can solve the impasse.
Lyubimov has shown that the neutrino has mass."
Zel'dovich cries, "Pancakes! The dark matter's HOT."
Carlos Frenk, Simon White, Marc Davis say, "NOT!
Quasars are old, and the pancakes must be young.
Forming from the top down it can't be done."
So neutrinos hit the skids, and the picture's looking black.
But California laid-back, Blumenthal & Primack
say, "Don't have a heart attack.
There's lots of other particles.
Just read the physics articles.
Take this pretty theory that's called supersymmetry.
What better for dark matter than the L-S-P?
The mass comes in at a ~ keV,
and that's not hot, that's warm."
Jim Peebles says, "Warm? Don't be half-hearted.
Let's continue the trend that we have started.
I'll stake out a position that's bold:
dark matter's not hot, not warm, but COLD."
Well cold dark matter causes overnight sensations:
hand-waving calculations,
computer simulations,
detailed computations of the background fluctuations.
Results are good, and the prospects look bright.
Here's a theory that works! Well, maybe not quite.

Dark matter: Do we need it? What is it? Where is it? How much?
Where is it? How much? Where is it? How much?

We have another puzzle that goes back to Robert Dicke.
Finding a solution has proven kind of tricky.
The CMB's so smooth, it's as if there'd been a compact
between parts of the universe that aren't in causal contact.
Alan Guth says, "Inflation,
will be our salvation,
give smoothness of the universe a causal explanation,
and even make the galaxies from quantum fluctuations!
There is one prediction, from which it's hard to run.
If inflation is correct, then Omega should be one."
Observers say, "Stop, no, sorry, won't do.
Look at these clusters, Omega's point 2."
The theorists respond, "We have an explanation.
The secret lies in biased galaxy formation.
We're not short of critical mass density.
Just some regions, are missing luminosity."
Observers roll their eyes, and they start to get annoyed,
But the theorists reply, "There's dark matter in the voids."

Dark matter: Do we need it? What is it? Where is it? How much?
Do we need it? Do we need it? Do we need it? Do we need it?

Along comes Moti Milgrom,
who's here to tell us all:
"This dark matter claptrap
has got you on the wrong track.
You're all too mired in conventionality,
wedded to your standard theory of gravity,
seduced by the elegance of General Relativity.
Just change your force law, that's the key.
Give me one free parameter, and I'll explain it all."
"Not so," claim Lake, and Spergel, et al.,
"On dwarf galaxies, your theory does fall."
The argument degenerates; it's soon a barroom brawl.

Dark matter: Do we need it? What is it? Where is it? How much?
What is it? What is it? What is it? What is it?

New observations hit the theory like an ice cold shower.
They show that cold dark matter has too little large scale power.
Says Peebles: "Cold dark matter? My feeblest innovation.
An overly aesthetic, theoretical abberation.
Our theories must have firmer empirical foundation.
Shed all this extra baggage, including the carry-ons.
Use particles we know, i.e., the baryons.
Others aren't convinced, and a few propose a mixture
of matter hot and cold, perhaps with strings or texture.
But nowadays most physicists are captured by the synergy
of inflation, cold dark matter, and repulsive dark energy.
Lambda or quintessence makes the whole picture integrate
by causing the expansion of the universe to accelerate.
New physics is exciting, and it gives us more to do.
Before we had one mystery. Now we have two.

So now you've heard my lecture, and it's time to end the session
with the standard closing line: Thank you, any questions?

Mp3看这里：http://www.symmetrymagazine.org/files/200702/darkmatterrap.mp3