(CBS) A weekly commentary by CBS News correspondent Andy Rooney.

Saturday morning, I went out to get the newspaper about seven o'clock. A stranger I passed nodded and said, "Have a nice day."

It was friendly of him but it didn't help my day. None of us had a nice day. At about 9 o'clock, we had a death in the family.

We search for something good about the worst things that happen in our lives and the only good thing about the disaster that took seven special people and our spaceship Columbia out of the sky is that it has brought us together. For this brief time, there is a warmth among us that didn't exist Friday.

It didn't happen to five men and two women alone - it happened to all of us. President Bush said it, we're together in our grief.

For this terrible time, we are not Republicans or Democrats.

We are not Protestants, Catholics, Jews or atheists. We're Americans together with the same awful feeling in our stomachs.

The purpose of exploring the mysterious space beyond our planet has been to improve life here on Earth. The more we know about what's out there, the easier it will be to change life for the better here. We don't do it often, but we're even thinking of future generations.

It has always been the brave men and women who have changed things for the better. The Wright Brothers risked their lives to prove we could fly.

Many of the soldiers who fought our wars were brave men who risked their lives to change the course the world was taking. The seven who died when the Columbia disintegrated were brave men and women.

It isn't bravery when we do some foolish thing for personal glory. The astronauts who waved goodbye and climbed on board the Columbia knew better than the rest of us how dangerous their mission was.

Looking at these pictures of them before their flight, it's difficult to suppress tears. Great, smiling people assuring us that they are not afraid, even though they must have been afraid.

If brave men and women never died, there would be nothing special about bravery. Cautious living is comfortable and safe, but it is not what made this nation great. The Pilgrim fathers were not cautious explorers. Casper Milquetoast was not one of our Revolutionary War heroes. We have lost seven brave people, trying to make things better for those of us here on Earth.

There is nothing good to say about it.