OK, so what's the speed of dark?

好吧，那么黑暗的速度呢？

youdao

That's because they use a model of dark matter that decays into certain types of particles such as heavy quarks and travels at the same speed no matter what the temperature is.

由于他们采用的暗物质模型只能衰退为诸如重夸克这样的特定粒子，并且运行速度平稳，未受温度影响。

youdao

Astronomers who study star clusters have noticed that the speed at which a star of a given mass spins (measured by tracking cool, dark spots on the surface) also seems to vary predictably with age.

研究星团的天文学家已经注意到质量一定的行星(通过追踪表面阴暗冷却斑点来测量)，其旋转速度随着其星龄呈现可预测性的变化。

youdao

What is believed to be causing this increase in the speed of expansion is called dark energy, making up more than 70% of the mass-energy - all of the "stuff" - of the Universe and the focus of the DECam's mission.

BBC: Dark energy camera snaps first images ahead of survey

The high-speed traders whom the exchanges desperately want to retain or win back from the dark pools are part of the reason the stock market looks so scary to individuals these days.

FORBES: Does NYSE's 4.8% Dividend Yield Make It A Bargain?

The so-called manual-block system takes the place of a dozen separate signals that help drivers adjust their speed and avoid colliding with other trains in the dark tunnels.

WSJ: PATH's Road Back Is Rocky