John M. Grunsfeld Quotes

The bottom line is, like, one in five stars has at least one planet where life might spring up. That's a fantastically large percentage. That means in our galaxy, there's on the order of tens of billions of Earth-like worlds.

It now appears that essentially every star has a planetary system. In the very beginning, we thought at best half.

I do a lot of work with NASA and am involved in research projects studying planetary evolution, Earth-like planets, and potential conditions for life elsewhere.

There are millions of stars out there. It is difficult to think that life does not exist in any one of them.

The universe is almost 14 billion years old, and, wow! Life had no problem starting here on Earth! I think it would be inexcusably egocentric of us to suggest that we're alone in the universe.

The Moon and Mars were the two most likely candidates for life in the solar system; what exists beyond our solar system is mere guesswork.

We're going to understand that there is life on other bodies in the solar system.

There's life all over this universe, but the only life in the solar system is on earth, and in the whole universe we are the only men.

We think that life develops spontaneously on Earth, so it must be possible for life to develop on suitable planets elsewhere in the universe. But we don't know the probability that a planet develops life.

A century ago, scientists believed there was only one obvious stomping ground for alien biology in our solar system: Mars. Because it was reminiscent of Earth, Mars was assumed to be chock-a-block with animate beings, and its putative inhabitants got a lot of column inches and screen time.

How can the human race be, like, the only living form in the universe? There have to be other life forms out there. I believe it.

When I grew up as a kid, we didn't know there were any other planets outside of our own solar system. It was widely speculated that planet formation was an incredibly rare event and that it's possible that other planets just don't exist in our galaxy, and it's just this special situation where we happen to have planets around our sun.

I think Pluto has to be considered among the places in the solar system that are possible homes for life.

One of the first thoughts I had, when doing early exoplanet research, was that Earth and its many companions seemed very different from the planetary systems we were detecting.

Most of the solar system resides beyond the orbits of the asteroids. There is more to learn there about general planetary processes than on Mars.

It's quite likely that planets and solar systems like ours could be forming in other galaxies in great numbers.

We should be ready to reach out beyond our planet and beyond our solar system to find out what is really going on out there.

The existence of life beyond Earth is an ancient human concern. Over the years, however, attempts to understand humanity's place in the cosmos through science often got hijacked by wishful thinking or fabricated tales.

I believe that there may be intelligent life on other planets.

It might be arrogant to think that we're the only living creations in all of the solar systems that there are. Space is so vast.

I am sorry to say that there is too much point to the wisecrack that life is extinct on other planets because their scientists were more advanced than ours.

It's just too egotistical to think that we are the only lifeform in the universe.

Mars still remains the astrobiology community's number one choice for 'nearest rock with life,' but there are many researchers who argue that the moons of Jupiter are better bets. In particular, Europa, Ganymede, and Callisto are all thought to hide vast oceans of liquid water beneath their icy, outer skins.

I haven't a clue if there is life on other planets but I'd be charmed if we found a unicellular organism on Mars. It would change our whole concept of life on Earth.

Should we find a second form of life right here on our doorstep, we could be confident that life is a truly cosmic phenomenon. If so, there may well be sentient beings somewhere in the galaxy wondering, as do we, if they are not alone in the universe.