You've urged a
methodical approach to looking for life with your CoLD scale,
ranking possible detections from one to seven.
Why do we need
such a scale?
A couple of
years ago, scientists came out and said they'd seen phosphine
in the atmosphere of Venus.
At the level
they saw it, which was enormous, that led them to believe life
was one of the major possibilities. On the CoLD scale, where
seven is "we found life," it is "one." It didn't even make it to
was contamination in their signal and it may not even be
phosphine and we can't reproduce it.
So we have to
do a better job in communicating.
We see methane
all over the place on Mars. Ninety-five percent of the
methane we find here on Earth comes from life, but there's a few
percent that doesn't.
We're only at a
CoLD Level 3, but if a scientist came to me and said,
instrument that will make it a CoLD Level 4," I'd fund that
mission in a minute...
jumping to seven, they're making that next big step, the right
step, to make progress to actually finding life in the solar
we've got to do, stop screwing around with just crying wolf.
The search for
life on Mars has been a focus for NASA for so long, starting in
1976 with the Viking 1 and 2 landers and later with missions
from the 1990s onward.
surprised we haven't found life in that time?
Yes and no.
doing now is much more methodical, much more intelligent in the
way we recognize what signatures life can produce over time. Our
solar system is 4.5 billion years old, and at this time, Earth
is covered in life.
But if we go
back a billion years, we would find that Venus was a blue
planet. It had a significant ocean. It might actually have had
life, and a lot of it. If we go back another billion years, Mars
was a blue planet.
We know now
Mars lost its magnetic field, the water started evaporating and
Mars basically went stagnant about 3.5 billion years ago.
We would like
to have found life on the surface.
We put the
Viking landers in a horrible place because we didn't know where
to put them - we were just trying to put them down on the
surface of Mars.
It was like
putting something down in the Gobi Desert. We should have put
them down in Jezero Crater, in this river delta we're at right
now with the
Perseverance rover, but we didn't even know it existed at
One of the
Viking experiments indicated there was microbial life in the
soils, but only one of the three instruments did, so we couldn't
say we found life. Now we'll really, definitively know because
we're going to bring
We didn't know
it would need a
sample return mission.
previously suggested it might be possible to terraform Mars by
placing a giant
magnetic shield between the planet and the sun, which would
stop the sun from stripping its atmosphere, allowing the planet
to trap more heat and warm its climate to make it habitable.
Is that really
stripping, and the pressure is going to increase. Mars is going
to start terraforming itself.
That's what we want:
the planet to
participate in this any way it can...
pressure goes up, the temperature goes up.
The first level
of terraforming is at 60 millibars, a factor of 10 from where we
are now. That's called the
Armstrong limit, where your blood
doesn't boil if you walked out on the surface.
If you didn't
need a spacesuit, you could have much more flexibility and
mobility. The higher temperature and pressure enable you to
begin the process of growing plants in the soils.
several scenarios on how to do the magnetic shield. I'm trying
to get a paper out I've been working on for about two years.
It's not going
to be well received. The planetary community does not like the
idea of terraforming anything. But you know. I think we can
Venus, too, with a physical shield that reflects light.
We create a
shield, and the whole temperature starts going down.
In 2015, NASA approved
Europa Clipper mission to search for signs of life on
Jupiter's moon Europa, set for launch in 2024, following the
detection of plumes erupting from its subsurface ocean in 2013.
Did you want
to see that mission happen sooner?
Oh, yeah, I
would love to have seen it earlier, but it wasn't going to
certain series of missions that are so big they're called
strategic missions. For them to actually happen, the stars have
You have to
propose it, have a solid case work, go to the NASA
administration and then pitch it to Congress. Every year, I
proposed a Europa mission. Every year.
administration was not interested in going to Europa.
The plumes on
Europa are what made the Europa mission happen. I was at an
American Geophysical Union meeting in 2013. Several of the
scientists were going to give a talk on
a plume with Hubble on Europa, and I go, "Oh, my God."
I said this is
fantastic, I want to do a press conference.
I call back to
NASA headquarters, and they pulled it off. I took that
information back with me to headquarters and added that into the
story of Europa.
turned the corner.
we should do this."
against putting a lander on the mission. Did you want one?
I would love a
lander, but it's not in the cards.
It makes the
mission too complicated, but everything we do on Clipper feeds
forward to a lander.
I insisted that
we had a high-resolution imager to the point whereas we fly over
certain areas, we're going to get the information we need to go,
right there, and safely."
Europa has got
some really hazardous terrains, so if we don't get the
high-resolution imaging, we'll never be able to land.
You want to
take a step, but not a huge step. You fail when you do that.
Viking is that example, where we took too big a step.
We didn't know
where to go, we didn't know enough about the soils or the toxins
in the soils. We hadn't really gotten a good idea where water
was on the planet in the past.
There were 10
things we should have known before we put the two Vikings on the
Are you still
going to work on scientific papers in your retirement?
I've got the
Mars paper to do. I have a Europa paper I'm writing right now. I
have an astrobiology book I'm doing. I have an insatiable
appetite for science...