New atomic clocks are more accurate than those used to define the second, suggesting the definition might need to change ...

从古埃及的日晷到现代的原子钟，人类对时间测量的精度不断提升。而如今，光学钟的精确度已超越了当前以铯-133原子跃迁定义的“秒”。这引发了一个关键问题：我们是否应该重新定义时间的基本单位？本文将系统解析当前时间计量的框架、光学钟的革命性突破，以及重新定 ...

In the hush between star-bright infinities and the hum of everyday tasks, a quiet summons persists. No single measurement or ...

All the snow last week and the cold air this week is making for some dangerous temperatures.But how can snow, make the cold ...

In discussions of the pros and cons of this procedure, potential risks from radiation exposure frequently are ignored. In this analysis, Columbia University researchers estimated risks for cancer ...

Galaxies, planets, black holes: to most people, everything about our Universe sounds and feels enormous. But while it's true that much of what happens millions of light years away is large, there ...

Radiotherapy, or radiation therapy, is the clinical use of high energy rays (ionizing radiation) to induce DNA damage in all exposed cells to ultimately kill cancer cells or prevent cancer growth.

In a political landscape that is fully intent on otherizing the Black experience, it’s more important than ever to listen to Black voices and experience Black stories. Netflix’s Black Stories ...

Calculating your body mass index (BMI) involves using a simple formula with your weight (in pounds or kilograms) and height (in inches or meters). BMI is used to estimate your body fat and establish ...

Each February, people across Canada participate in Black History Month events and celebrations that honour the legacy and contributions of Black people in Canada and their communities. The 2025 theme ...