Where is everyone? We have been listening for messages from outer space for more than half a century, and so far... silence, why? Are we truly alone in the universe? Or is everyone else acting like us and just doing a lot of listening? Maybe we need to be louder. Maybe we need to send more messages out there. But how do you write a letter to an extraterrestrial whose language and culture and biology and mind we have no concept of? And what do you say?
Given all of the unknowns about what they might behave, should we say anything at all?

The last episode examines the fragile interdependence that exists between forests' wide variety of residents, including bald eagles, hunting dogs and Siberian tigers.
Over half of all the world's trees, evergreen and deciduous, stand in great assemblies. For many of us, they are places of mystery and darkness. They are key to our climate, and home to countless unique species. The boreal forest contains 750 billion trees, and it stores over 40 percent of the world's carbon, making it a vital element in the fight against climate change. In the past, we have destroyed them without hesitation. Yet, forests do have an astonishing ability to recover. If we choose to give forests time and space, they could reclothe the earth with much of the rich and varied communities of animals and plants of which we have, so recently, robbed it. A future with more forests is key to the resilience of our planet.

How is the universe put together? How is it built? And how does it actually work? How the Universe Works Series 8 shows the inner workings of our planet, the solar system, the galaxies and the universe itself.
In the first episode, if a massive asteroid collides with earth, it could end life on our planet as we know it. New discoveries and cutting-edge tech reveal just how close we are to apocalypse and what it would take for the world's leading space agencies to stop it.

NASA is on a mission to send humans to Mars within just 15 years, but to reach this next frontier of space exploration, experts must discover new technology and cutting-edge science that protects astronauts from the Red Planet's deadliest killers.

We're unlocking the secrets of our planet's voyage and discovering that earth's journey affects us all. The Earth is extremely dynamic. It is spinning on its axis, it's whirling about the sun and it's corkscrewing throughout the this galaxy. And there is the fact than Andromeda and the Milky Way are currently 2.5 million light-years apart, but they're hurtling towards each other at over 250,000 miles an hour. A collision is inevitable. As stars, dust, and gas swirl around each other, gravitational interactions could slingshot our solar system out into intergalactic space.

The First Amendment and the very idea of free speech are under attack in America today. A growing number of Americans don't believe you have the right to speak your mind if what you have to say might offend someone, somewhere. They advocate for 'safe spaces' in which people won't be offended by ideas they may find troubling. But is that what America is about?
In No Safe Spaces, comedian and podcast king Adam Carolla and radio talk show host Dennis Prager travel the country, talking to experts and advocates on the left and right, tour college campuses, and examine their own upbringings to try to understand what is happening in America today and what free speech in this country should look (and sound) like.