Lisa Kaltenegger: "We have discovered a planet that tells us what the Earth will be like in 5 billion years"

Lisa Kaltenegger (Kuchl, Austria, 45 years old) wants to be the first person to find life on a planet beyond the solar system.

In 1995, when Michel Mayor and Didider Queloz discovered the first exoplanet, young Kaltenegger had just entered university to study engineering and astrophysics.

Less than 30 years later, we know of more than 5,000 of these worlds.

About 40 of them are the size of Earth and may contain liquid water.

Kaltenegger, director of the Karl Sagan Institute at Cornell University (USA), leads a project to observe the only three of these worlds that we can reach with current telescopes.

"There is a fascinating fact," she explains in this interview given in Armenia during the Starmus VI festival.

“Now we know that in our galaxy alone, the Milky Way, there may be 40.

billion habitable planets.

And in the universe there are billions of galaxies.

I am often asked if there is life in the universe.

With these numbers, the surprise will be if we don't find it."

Ask.

What is the next big goal in the search for exoplanets?

Response.

Space Telescope

can see the chemical composition of the atmosphere of habitable rocky planets;

other lands.

There are combinations of molecules that could not be there if there were no life.

We call them biomarkers.

If we find this combination on a rocky planet, there is no other option: there has to be life.

Q.

What combination are you looking for?

A.

Oxygen and methane.

The two together transform into carbon dioxide and water.

Methane can come from geological sources.

But if there are also large amounts of oxygen, this can only come from living beings.

Q.

Is it just a matter of time?

R.

Yes. We are going to take a while, because obviously the

is not dedicated only to this topic.

For now, Earth is the only planet we know of where there is life.

Throughout its existence this planet has changed a lot.

I ask my students on the first day of class what they would take with them if they could travel back in time.

Many tell me that a camera, a mobile.

The truth is that the gases on Earth have changed so much that if you travel to the distant past and open the door, you die because you can't breathe.

That change of the predominant gases that happened on Earth can be observed in the light that other planets emit.

In this way we will be able to see planets that do not have life, but that may have it in the future if it follows our same path.

Q.

How can you know that a planet will follow that course?

A.

In my group we make models of what the Earth's atmosphere was like at all stages from its birth until now.

We want to do the same with all objects in the solar system.

We have also compiled a catalog of the colors of life.

We have searched for more than 100 species of microbes in many different ecosystems, deserts, glaciers..., to determine what kind of light they emit and what they would look like with a telescope.

Imagine a planet completely covered in water, an ocean world.

It is possible that there are green or red algae similar to those on Earth and that my telescope can pick it up.

Or think of corals on land that fluoresce when exposed to ultraviolet radiation.

We may suddenly see such a flash.

“In three years we will know if there are signs of life on exoplanets similar to Earth”

Q.

Will the

be able to see the surface of planets like Earth?

A.

No. But some changes on the surface have repercussions in the atmosphere.

We are seeing it on Earth with the accelerated melting of glaciers.

The number of microbes living in them is concentrated.

This decreases the amount of light reflected by the ice, which receives more heat and melts faster.

In this way, if you see a very cold planet, but it has gases of possible organic origin, it is possible that there are also living microbes there.

Q.

How long will it take to check if there is oxygen or methane on any terrestrial planet?

R.

With

we only get to see three of those 40 habitable terrestrial planets.

In these we are going to take about three years to know if there is water, oxygen or methane.

Q.

If they find the signal, what would be the next step?

R.

First we are going to celebrate it in a big way.

Then, before we say anything, we will analyze it until we are sure that there is no other possible explanation.

If confirmed, more time would have to be spent observing with all possible telescopes.

We could also make a specific telescope to study a single planet so that we can capture the light reflected by its clouds and its surface.

Q.

How do you think people would react to such a discovery?

R.

I think they will not be so surprised.

My first-year students have already been born in a world in which the existence of exoplanets was known.

It's normal for them.

Think of the next generation.

There is not going to be so much shock when we discover life.

Many will think that it had already been discovered, as is the case with Mars.

It will not scare us so much.

Q.

Will the world not change so much?

A.

Of course.

It will change our position in the cosmos.

In the history books there will be a before and after extraterrestrial life, just as there is a before and after Christ.

Q.

Your team has discovered a very peculiar Earth recently...

A.

Yes, the habitable zone has limits;

if you go too close you become Venus and if you go a little further than necessary, you become Mars.

But really the limit is more diffuse.

What we have now found is a solar system called Speculoos 2. There are two planets here.

One of them is too hot.

The other I call the world on the edge of the knife, because it is right on the border between Venus and Earth.

This planet is very interesting to know what will happen at some point when the Sun begins to die, becomes much larger and the Earth becomes scorching.

It will be in about 5,000 million years.

Thanks to this planet we will know with what exact level of radiation we will begin to lose all the water on the planet.

This world is like traveling to our future in 5 billion years.

Q.

The discovery of extraterrestrial life will make the story of many religions inconsistent. Do you think there will be room for God?

R.

I see no conflict between religion and science.

One is based on data and the other on beliefs.

Our Christian religion, like any other, is a story written by human ancestors in the context of their time.

That is why they said that the apostles were all men.

It is difficult to conceive a story like this now.

The most important thing is not to take these stories at face value.

I believe in something, but I don't know what it is.

It is possible that God is just something that was there before the

and then the laws of physics and evolution took over.

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