Never mind the aliens, ... yet.
The most suprising event this year is not the assassination of the Iranian top general Qasem Soleimani, BLM, wildfires ore Covid-19 but the release of U.F.O footages from 2005/2015/2017 by the U.S goverment.
Aliens smell like farts. If they land they will stink the place out.
https://www.popularmechanics.com/space/deep-space/a29932234/what-would-aliens-smell-like/...Which led my son to one inescapable conclusion: If aliens exist, they probably smell like farts.
I dont know enough about farts, Mars, or aliens to refute him, so I reached out to somebody who does: Clara Sousa-Silva, a molecular astrophysics postdoctoral associate at MIT.
Your son is absolutely correct in his inference, she told me. Most of my work in astrobiology looks at anaerobic environments, which have a lot in common with the environments that produce farts. So, yes, aliens are reasonably likely to smell like farts.