Expert Voices: Op Ed & Insights

The impact of Apollo 8's "Earthrise" picture – the sight of the Earth from the moon – now seems even greater than that of the first landing.

I use moon and Mars rocks in my teaching and have a modest collection of meteorites. I marvel at the fact that I can hold in my hand something that is billions of years old from billions of miles away.

What astronomers can measure using telescopes is not what we really want to know – instead, we calculate the properties we're interested in studying by observing and interpreting apparent properties from afar.

Unlike physical theories describing the other three fundamental forces in physics, the general theory of relativity has only been tested in weak gravity.

Measuring the ages of planets and stars helps scientists understand when they formed and how they change – and, in the case of planets, if life has had time to have evolved on them.

While the Pentagon sees the Space Force as a tool to fight the last war here on Earth, its leaders must prepare for its real role in space, on the moon and beyond.

It’s hard to keep a spacecraft cool, but ongoing research on the International Space Station might yield a solution.

With NASA planning more missions to space in the future, scientists are studying how to mitigate health hazards that come with space flight.

The challenges of settling Mars stretch beyond the boundaries of rocket technology, impacting our biology and fundamentally questioning our identity as a species.

There's a slight chance Comet Nishimura might brighten unexpectedly. Astronomer Jonti Horner explains what to expect.