---
title: "NASA Is Hunting Alien Civilizations by Looking for Their Pollution"
description: "NASA scientists say they can hunt for alien civilizations by looking for industrial pollutants like nitrogen dioxide in exoplanets' atmospheres."
date: "2021-02-11"
modified: "2021-02-11"
authors:
  - name: "Dan Robitzski"
    link: "https://futurism.com/authors/danrobitzski"
url: "https://futurism.com/the-byte/nasa-hunting-alien-civilizations-pollution"
categories:
  - "Environment"
  - "NASA"
  - "Pollution"
  - "Science & Energy"
  - "Space"
tags:
  - "extraterrestrial life"
  - "technosignatures"
  - "the digest"
---

# NASA Is Hunting Alien Civilizations by Looking for Their Pollution

![NASA scientists say they can hunt for alien civilizations by looking for industrial pollutants like nitrogen dioxide in exoplanets' atmospheres.](<https://futurism.com/wp-content/uploads/2021/02/nasa-scientists-hunting-aliens-pollution.jpg>)
*\<em\>Image: NASA/Jay Freidlander\</em\>*

## Garbage Day

A team of NASA scientists is taking a clever approach to hunting for alien life: scanning exoplanets for signs of air pollution.

Just as pollutants like nitrogen dioxide and greenhouse gases in Earth's atmosphere are an indication of human activity below, a team of NASA researchers are now looking for pollutants on other, potentially-habitable exoplanets as a new alien technosignature, meaning a sign of an [advanced extraterrestrial civilization](<https://futurism.com/nasa-harvard-hunt-technological-civilizations>). Their [study](<https://arxiv.org/abs/2102.05027>), posted online and accepted for publication in *The Astrophysical Journal*, is the first to add nitrogen dioxide as a potential technosignature — giving scientists a new tool in the search for life.

## Sniff Test

The idea of sniffing out aliens based on their pollution [isn't a new one](<https://futurism.com/atmospheres-distant-planets-guide-scientists-search-alien-life>). But adding nitrogen dioxide, a byproduct of burning fossil fuels in power plants or vehicle engines, helps broaden the search.

"Therefore, observing \[nitrogen dioxide\] on a habitable planet could potentially indicate the presence of an industrialized civilization," lead study author Ravi Kopparapu, a researcher at NASA's Goddard Space Flight Center, [said in a press release](<https://www.nasa.gov/press-release/goddard/2021/technosignature>).

## Natural Gas

The problem is that many worlds might have naturally-occurring nitrogen dioxide in their atmospheres, especially since it can be given off by volcanic activity. So part of the new study was finding a way to model the amount of nitrogen dioxide there *should* be on a given exoplanet.

"If we observe more \[nitrogen dioxide\] than our models suggest is plausible from non-industrial sources," study coauthor and Goddard researcher Giada Arney said in the release, "then the rest of the \[nitrogen dioxide\] might be attributed to industrial activity."

**READ MORE:** [NASA Study: To Find an Extraterrestrial Civilization, Pollution Could Be the Solution](<https://www.nasa.gov/press-release/goddard/2021/technosignature>) \[NASA\]

**More on technosignatures:** *[NASA Funds Harvard Hunt for Alien “Technological Civilizations”](<https://futurism.com/nasa-harvard-hunt-technological-civilizations>)*

## Author
Dan Robitzki is a senior reporter for Futurism, where he likes to cover AI, tech ethics, and medicine. He spends his extra time fencing and streaming games from Los Angeles, California.

### Author social links  
[Twitter](<https://x.com/danrobitzski>)