Earth Observation Archives

March 3, 2023March 3, 2023 by Nancy Atkinson

Why are Earth’s Hemispheres the Same Brightness? New Research Solves a 50-year-old Mystery.

The Blue Marble from Apollo 17 — The Blue Marble image of Earth from Apollo 17. Credit: NASA

NASA’s Apollo program most notably explored the Moon. But it also helped us study the Earth as well, as it provided some of the first high-resolution images of our whole planet, like the famous “Blue Marble” photo taken by the Apollo 17 astronauts.

However, these full-Earth photos revealed a mystery. Scientists expected that Earth’s two hemispheres, the north and south, would have different albedos, a difference in the amount of light they reflect. This is because Earth’s northern and southern hemispheres of Earth are quite different from each other. The southern hemisphere is mostly covered with dark oceans, while the northern hemisphere contains vast land areas that are much brighter than the oceans

Yet, when observing Earth from space, the two hemispheres appear equally bright.

This symmetry in brightness has been a puzzle for over 50 years. But now, a new study shows that the albedos are roughly the same because of the increased clouds and storms in the southern hemisphere.

January 20, 2023January 20, 2023 by Evan Gough

Light Pollution is Obscuring the Night Sky. RIP Stargazing

A startling analysis from Globe at Night — a citizen science program run by NSF’s NOIRLab — concludes that stars are disappearing from human sight at an astonishing rate. Image Credit: NOIRLab/NSF/AURA, P. Marenfeld

A citizen science initiative called Globe at Night has some sobering news for humanity. Our artificial light is drowning out the night sky for more and more people. And it’s happening more rapidly than thought.

January 13, 2023January 13, 2023 by Matt Williams

NASA Satellites can Pinpoint the Exact Locations of Excessive CO2 Emissions

Carbon dioxide in Earth's atmosphere if half of global-warming emissions are not absorbed. Credit: NASA/JPL/GSFC

In 2013, the National Oceanic and Atmospheric Administration (NOAA) reported that atmospheric concentrations of carbon dioxide (CO₂) had reached four-hundred parts per million (ppm) for the first time since the Pliocene Era (ca. three million years ago). According to the IPCC’s Sixth Assessment Report (AR6), “excess carbon dioxide” in our atmosphere will result in a global average temperature increase of between 1.5 and 2 °C (2.7 and 3.6 °F) by 2030. This will significantly affect ecological systems worldwide, including species extinction, droughts, wildfires, extreme weather, and crop failures.

Aside from curbing emissions, these changes call for mitigation and adaptation strategies and climate monitoring. This is the purpose of NASA’s Orbiting Carbon Observatory (OCO) 2 and 3 missions, twin satellites that make space-based observations of CO2 in Earth’s atmosphere to understand the characteristics of climate change better. Using the world’s fifth-largest coal-fired power plant as a test case, a team of researchers used data from OCO 2 and 3 to detect and track changes in CO₂ and quantify the emissions produced below.

December 15, 2022December 15, 2022 by Evan Gough

NOAA’s New Weather Satellite is Operational, and its Pictures of Earth are Gorgeous

Polar-orbiting satellites capture swaths of data throughout the globe, and observe the entire planet twice each day. The global mosaic, captured by the VIIRS instrument on the recently launched NOAA-21 satellite, is a composite image created from these swaths. Image Credit: NOAA STAR VIIRS Imagery Team.

You’d have to be in some kind of sense-of-wonder-repressed coma not to appreciate satellite images of Earth. If you are, then images from the NOAA’s newest satellite might pull you out of it.

And they’re only a taste of the fascinating images that it will provide.

October 31, 2022October 31, 2022 by Carolyn Collins Petersen

Good News! The Ozone Hole is Continuing to Shrink

earth's atmosphere has an ozone hole (not seen here) — Earth’s atmosphere seen from space. The top layer of the stratosphere is the ozone layer, which protects us from harmful solar UV. Scientists are tracking the ozone hole over the Antarctic. Credit: NASA

Most of us don’t think about ozone as we go about our daily lives. Yet, this pale blue gas plays a huge role in keeping our planet habitable. There’s a layer of it in Earth’s stratosphere, and it absorbs most of the ultraviolet radiation streaming from the Sun. Without the ozone layer, the UV would cause severe damage to most life on Earth. What would happen if we had an ozone hole?

October 14, 2022October 16, 2022 by Evan Gough

If Earth Were an Exoplanet, it Would Still be Tricky to Figure Out if There’s Life Here

Earth as seen by the JUNO spacecraft in 2013. Credit: NASA/JPL-Caltech/SwRI/MSSS/Kevin M. Gill.

How would Earth appear to alien astronomers? What would their observations tell them about Earth if they searched the heavens for signs of habitability like we are? It’s a fun thought experiment.

But the experiment is more than just fun: it’s scientifically instructive. In many ways, it’s easier to study our planet and how it appears and then extrapolate those results as far as they go.

A new study shows that finding evidence of life on Earth may depend on the season alien astronomers are observing.

October 8, 2022October 8, 2022 by Nancy Atkinson

The Methane Released From the Damaged Nord Stream Pipeline is Visible From Space

On September 20, 2022 a GHGSat satellite observed the area of the Nordstream pipeline break, and saw an estimated emission rate of methane of 79,000 kg per hour – making it the largest methane leak ever detected by GHGSat from a single point-source. Credit: GHGSat and ESA.

On September 26, 2022, leaks were discovered in the underwater Nord Stream 1 and 2 gas pipelines, located near Denmark and Sweden. Both pipelines are owned by Russia and were built to transport natural gas from Russia to Germany through the Baltic Sea. Officials have said the leaks were caused by deliberate action, not accidents, and were likely intentional sabotage. While accusations have abounded, the motives behind the damage are not yet known.

Seismic disturbances in the Baltic Sea were detected, and officials said that while neither pipeline was transporting gas at the time of the blasts, they still contained pressurized methane, which is the main component of natural gas. The methane has now spewed out, producing a wide stream of bubbles on the sea surface which are visible from various satellites in Earth orbit.

October 3, 2022October 3, 2022 by Nancy Atkinson

Gaze Down Into the eye of Hurricane Ian, Seen From Orbit

On September 28, the Landsat 8 satellite passed directly over Ian’s eye as the storm approached southwest Florida. Credit: US Geological Survey.

NASA and NOAA satellites — as well as astronauts on the ISS — captured some stunning imagery of Hurricane Ian, as seen from orbit. Our lead image shows an eerie view of the hurricane’s eye on September 28. The Landsat 8 satellite passed directly over Ian’s eye as the storm approached southwest Florida.

August 16, 2022December 16, 2022 by Carolyn Collins Petersen

Satellites are Tracking Rivers of Garbage Flowing Across the Oceans

garbage patches in Earth's oceans — A a computational model of ocean currents called ECCO-2 that shows how garbage can be distributed across Earth's oceans. Courtesy NASA's Scientific Visualization Studio

There’s an ocean of human-made garbage floating through Earth’s seas. From plastic straws to beverage bottles and food wrappers, the ocean waters are this planet’s fastest-growing junkyard. Some of the plastic gets ground into little beads called microplastics, and ends up in the food chain, with humans at the top. For that reason, and many others, the European Space Agency is tracking ocean-bound plastics through the auspices of the MARLISAT project. It’s one of 25 efforts created to identify and trace marine litter as it moves through the world’s waterways. The ultimate goal is to help countries reduce ocean litter, particularly plastics.

July 14, 2022July 14, 2022 by Carolyn Collins Petersen

A New Instrument is Going to the ISS to Study the Climate Impact of Dust in Earth’s Upper Atmosphere

People often seem surprised when they learn that NASA doesn’t just look out to the other planets, stars, and galaxies. It’s also an agency that studies our own home planet—from space! And why not? Earth is part of the solar system, too. So, to that end, there’s a new Earth studies mission called EMIT on its way to the International Space Station. It’s designed to track dust as it moves from one place to another on our planet through through our atmosphere.

The official name of the mission is the Earth Surface Mineral Dust Source Investigation (EMIT, for short). It will use a high-tech imaging spectrometer to study dust around the globe over the next year.