T-42 Our Pale Blue Dot, Revisited

The iconic Pale Blue Dot image, reprocessed using modern techniques

Thirty years ago, on Feb. 14, 1990, our Voyager 1 spacecraft turned back toward its home for one last look. Almost 4 billion miles from the Sun, Voyager snapped the first-ever “family portrait” of our solar system.

In this family portrait, Earth is visible as a tiny blue dot. This image of Earth, a tiny point of light, is contained in a camera artifact that resembles a beam of sunlight.

The late Carl Sagan referred to this image of Earth in the title of his 1994 book, Pale Blue Dot. Sagan wrote: “That’s here. That’s home. That’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives.”

This year, we revisited the Pale Blue Dot image, using modern image-processing software and techniques that weren’t available in 1990. As we count down to Earth Day, we invite you to reflect on this new look at our home planet.

T-43: Aiding Response in Severe Weather

Computer model of Hurricane Sandy


In 2012, one of the largest recorded hurricanes hit New Jersey: Hurricane Sandy. The storm took 30 lives and damaged or destroyed at least 340,000 homes.

More than 2 million people lost power, and Sandy caused an estimated $70 billion in damage in the United States. NASA’s Short-term Prediction Research and Transition Center (SPoRT) gathered satellite imagery and data, providing timely data to forecasters and first responders to enhance preparation and recovery efforts.

In the immediate aftermath of Hurricane Sandy, the SPoRT team rapidly developed a prototype “blackout composite” from near real-time satellite data and produced false-color composites to identify damaged roads and homes across the affected states.

Response teams used these unique data to organize and allocate personnel, equipment and supplies, and to initiate recovery efforts quickly in areas in most need of assistance.

T-44: Sharing the View

NASA has been looking at Earth from space for more than 60 years. As our satellite fleet has grown and technology has improved, our view has become sharper and more expansive. For more than 20 years, NASA satellites have taken hundreds of daily images of our planet, letting us zoom in on fires, floods, hurricanes, volcanic eruptions and more.

We’ve made that data all available to the public, for research purposes and just to explore. NASA’s Worldview compiles more than two decades of satellite data to allow people to home in on places of interest and change their view from day to night or cycle through different observations, from vegetation and dust storms to ice bergs and energy output in population centers.

NASA logo with the blue circle replaced with EarthYou can even create and download your own still images or gifs to share how you view our world.

T-45: Women of NASA Earth Science

Today, we’re celebrating International Women’s Day with the women of NASA’s Earth Science Division. Earth science is for everyone, and across the agency, women are building satellites, conducting research in the field, and taking important measurements from space.

Meet just a small number of the women in Earth science at NASA:

The Earth Science division at NASA is currently led by Dr. Sandra Cauffman. She’s worked on missions exploring the solar system, astrophysics and is now the acting director of the Earth Science divisions. Currently, three of NASA’s four science divisions are led by women.

Dalia Kirschbaum with GPM

Dr. Dalia Kirschbaum is a research scientist and the Deputy Project Scientist for Applications for the Global Precipitation Measurement mission. She studies how precipitation affects landslides and works to improve landslide prediction models.

Africa Flores

From growing up in Guatemala to working with the SERVIR program – a joint effort between NASA and the U.S. Agency for International Development (USAID) – to help communities protect their natural resources, Africa Flores hopes her path sends a message to young women interested in science: “Don’t give up.”


Liz Hoy in the field

Dr. Liz Hoy studies Earth’s Arctic and boreal regions, looking at how fires affect carbon storage in a warming climate. She travels to Alaska and Canada during the summer with NASA’s Arctic Boreal Vulnerability Experiment field campaign.



Catherine Nakalembe with her sons

Dr. Catherine Nakalembe turned her love of geography into a career helping countries in Africa use NASA satellite data to improve food security – including her home country of Uganda. She often brings her twin sons with her when she travels for field work.


Kelly Brunt in Antarctica

Dr. Kelly Brunt is a scientist studying the cryosphere — Earth’s icy reaches. She uses ICESat-2 data to track how Antarctic ice sheets are changing in a warming world. About once a year, she travels to Antarctica to verify those measurements from the ground.

Carrie Vuyovich in Colorado

How much water is in winter snow? Dr. Carrie Vuyovich, lead for NASA’s Terrestrial Hydrology Snow program is working to find out. Carrie studies seasonal snow and how to measure it: Vital info for drinking water, climate, agriculture, ecosystems and more.

Melody Djam

Melody Djam is an engineer and the deputy project manager for one of the Landsat 9 instruments. Her team built and then tested the instrument by simulating the harsh environment of space before successfully integrating it into the spacecraft.

These are just a few of the women doing the important work of studying our home planet. We’ve highlighted even more on Twitter and head to nasa.gov/women for even more.

T-46: How NASA Observes Earth’s Atmosphere

Better and faster computers have improved how we model and study Earth. More information is the other piece of the puzzle.

Since 1980, the tenth anniversary of Earth Day, the number of observing systems, which includes satellites, weather balloons, and even instruments flown on commercial airlines, has dramatically increased—from 175,000 observations gathered over a six-hour period in 1980 to around 5 million observations in 2018.

NASA logo with the blue circle replaced with EarthThe Global Modeling and Assimilation Office (GMAO) at NASA Goddard Space Flight Center uses the Goddard Earth Observing System (GEOS) modeling and data assimilation system to produce estimates of Earth’s atmospheric state by combining short-term forecasts with observations from numerous observing systems. The GEOS modeling system helps us see Earth more clearly and better understand our atmosphere and how it changes.

T-47: Climate Modeling Then and Now

In 1970, a NASA computer model forecast temperature over boxes 250 miles wide. Now, NASA computer models can forecast temperature across boxes 7.5 miles wide.

Think about how much faster and better computers are today than in 1970. With better computing power, NASA can study our planet in new ways and at much higher resolution. Computer models of climate have changed dramatically since the first Earth Day.

In 1970, a NASA experiment* used a computer model to produce a forecast of global temperature. That model solved mathematical equations to forecast temperature across grid boxes 400 kilometers (250 miles) wide — about the length of the state of Maryland. All the data came from one single satellite: Nimbus 3.

In 2020, a global temperature forecast from NASA’s GEOS model uses grid boxes just 12 kilometers (7.5 miles) wide — narrower than the city of Baltimore. Every 6 hours, GEOS ingests 4 million observations from satellites and other sources and then runs a research forecast on a NASA supercomputer.

Today’s improved models run reliably accurate weather forecasts out to 10 days. They help save lives and property, including by better predicting hurricane tracks, intensity and winds days in advance. Models also make longer-term climate predictions that can assist farmers and governments in preparing for abnormally hot/cold or dry/wet periods.

View GEOS forecasts for yourself at:



*Jastrow, R. and M. Halem, 1970: Simulation Studies Related to GARP. Bull. Amer. Meteor. Soc., 51, 490–514, https://doi.org/10.1175/1520-0477-51.6.490. © American Meteorological Society. Used with permission.

T-48: Astronaut Photos of Earth

As astronauts orbit Earth, they can see the limb of the planet.

Astronauts living aboard the International Space Station are Earth’s human eyes in sky. The photos they snap from our orbiting laboratory do much more than create beautiful art. They have also helped power numerous scientific studies and support disaster response efforts.

From the Space Station, astronauts can see electric lights on Earth.

Crew Earth Observation images are currently supporting a number of urban night lighting studies, glacier and volcano monitoring, and studies of atmospheric processes such as the frequency of lightning flashes. The images also are used in ecological studies, including a collaborative project called Aviation Migration Aerial Surface Space (AMASS), which tracks bird migration routes and the effects of changes occurring along those routes. Crew Earth Observations have been ongoing since 1961 and more than 1,500,000 images have been taken during space station operations.

Astronauts photograph hurricanes and other storms to help study them from space.

Want to take a look at more of the images? Pictures taken by the crew are free to the public! You can access the database at any time at Gateway to Astronaut Photography of Earth.

T-49: Mapping U.S. Crops and Farmland from Space

Growing food is one of humanity’s most expansive and essential uses of the environment, and it’s something we can now track in great detail from satellites. From vast swaths of corn fields to smaller clusters of citrus groves, Landsat satellites help the U.S. Department of Agriculture (USDA) track what’s growing on America’s farmland. On a color-coded map, a patchwork of corn (yellow) and soybeans (green) span the Midwest, while a rainbow of crops cover California’s Central Valley.

Landsat, jointly managed by NASA and the U.S. Geological Survey, collects data-rich images of Earth’s land cover with a resolution that can detect individual farm fields. By combining Landsat data with information from other satellites and on-the-ground surveys, the USDA maps each crop and tabulates the acreages every year. The program started in 1997, grew to include all of the contiguous United States in 2009, and continues today.

NASA logo with the blue circle replaced with Earth

The crop data helps officials evaluate damage from floods, droughts and other natural disasters, while resource managers can use it to direct crop rotation, study land-use change and monitor water use.

T-50: Earthrise

Iconic Earthrise image showing Earth rising over the limb of the Moon with the NASA logo in the bottom left corner
Earthrise was taken on Dec. 24, 1968 from the Apollo 8 mission.

In 1968, humanity had its first look back at Earth from another world. Three astronauts on Apollo 8 orbiting the Moon peered out their capsule window and saw our home planet rising in the sky.

“We came all this way to explore the Moon, and the most important thing is that we discovered the Earth,” said William Anders, who snapped the iconic image that would become known as Earthrise.

Since NASA’s very beginning, we’ve kept a careful eye on Earth. From space, our view has shaped how humans see and understand our home. The Earthrise image, for example, helped inspire the first Earth Day 50 years ago. And our scientific observations from Earth orbit have shown how the planet is changing and point the way to solutions for environmental challenges around the globe.

Over the next 50 days leading up to Earth Day on April 22, we’ll bring you images and stories like this – some new, some familiar – every day to mark 50 years of celebrating our home planet.