An environmental scientist who is admired by Microsoft co-founder Bill Gates doesn’t like Elon Musk’s plan to colonize Mars. According to the scientist, the SpaceX CEO is delusional for wanting to leave Earth.

Recently, Musk unveiled SpaceX’s latest project dubbed as Starship, which will serve as the company’s main spacecraft to provide commercial spaceflights to Mars. For Musk, Starship will eventually ferry humans to the Red Planet in the hopes of colonizing it.

In order to establish a human colony on Mars, which has a very harsh environment, the SpaceX founder shared his controversial plans to terraform it. One of the plans proposed by Musk involves detonating multiple nuclear weapons on the planet. According to the tech mogul, doing so would change the planet’s environmental and atmospheric conditions and make it habitable.

Although most of the scientific community praised Musk for his ultimate goal of establishing a human colony on the Red Planet, others are not too happy about it. One of Musk’s critics is Vaclav Smil, a Czech-Canadian scientist who is focused on advancing research in the fields of energy, environment, population and economics.

Due to his scientific achievements, he has been named by Gates as one of his most favorite scientists.

According to Smil, Earth is currently dealing with a number of pressing matters including climate change. Instead of leaving the planet, Smil strongly believes that people should be more concerned about coming up with ways on how to solve these issues.

For Smil, leaving Earth is not an option. Even though there are planets out there that are considered habitable, Earth is still unique and well-suited for humans. For the scientist, this is the only planet where humans should live on. Because of this, he described Musk as delusional for wanting to leave Earth in order to live on Mars.

“Absolutely, because it’s the only planet we have, you know,” Smil said when asked about the importance of climate change on Earth, according to Express.

“You have to be a delusional Elon Musk to think that we can terraform Mars and leave this planet,” he added. We will never leave this planet.”

Europe's Mars Express Orbiter captures a dust storm raging at the edge of Mars' north polar ice cap on May 29, 2019. ESA/GCP/UPV/EHU Bilbao