Heat - Blog Posts

Earth’s Hot and It’s Cold 🎶(and We Can Tell from Space)

From people and pets to pens and pencils, everything gives off energy in the form of heat. We’ve got special instruments that measure thermal wavelengths, so we can tell whether something is hot, cold or in between. Hotter things emit more thermal energy; colder ones emit less.

We have special instruments in space, zipping around Earth and measuring the hottest and coldest places on our planet.

We can also measure much subtler changes in heat – like when plants cool down as they take up water from the soil and ‘sweat’ it out into the air, in a process called evapotranspiration.

This lets us identify healthy, growing crops around the world.

The instrument that can do all this is called the Thermal Infrared Sensor 2 (TIRS-2). It just passed a series of rigorous tests at our Goddard Space Flight Center in Greenbelt, Md., proving it’s ready to survive in space.

TIRS-2 is bound for the Landsat 9 satellite, which will continue decades of work studying our planet from space.

 Learn more about TIRS-2 and how we see heat from space: https://www.nasa.gov/feature/goddard/2019/new-landsat-infrared-instrument-ships-from-nasa/.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.

Global Temperature by the Numbers

The Year

4th Hottest

2018 was the fourth hottest year since modern recordkeeping began. NASA and the National Oceanic and Atmospheric Administration work together to track temperatures around the world and study how they change from year to year. For decades, the overall global temperature has been increasing.

Over the long term, world temperatures are warming, but each individual year is affected by things like El Niño ocean patterns and specific weather events.

1.5 degrees

Globally, Earth’s temperature was more than 1.5 degrees Fahrenheit warmer than the average from 1951 to 1980.

The Record

139 years

Since 1880, we can put together a consistent record of temperatures around the planet and see that it was much colder in the late-19th century. Before 1880, uncertainties in tracking global temperatures were too large. Temperatures have increased even faster since the 1970s, the result of increasing greenhouse gases in the atmosphere.

Five Hottest

The last five years have been the hottest in the modern record.

6,300 Individual Observations

Scientists from NASA use data from 6,300 weather stations and Antarctic research stations, together with ship- and buoy-based observations of sea surface temperatures to track global temperatures.

The Consequences

605,830 swimming pools

As the planet warms, polar ice is melting at an accelerated rate. The Greenland and Antarctic ice sheets lost about 605,830 Olympic swimming pools (400 billion gallons) of water between 1993 and 2016.

8 inches

Melting ice raises sea levels around the world. While ice melts into the ocean, heat also causes the water to expand. Since 1880, sea levels around the world have risen approximately 8 inches.

71,189 acres burned

One symptom of the warmer climate is that fire seasons burn hotter and longer. In 2018, wildfires burned more than 71,189 acres in the U.S. alone.

46% increase in CO2 levels

CO2 levels have increased 46 percent since the late 19th Century, which is a dominant factor causing global warming.

A persistent heatwave has been lingering over parts of Europe, setting record high temperatures and turning typically green landscapes brown.

The United Kingdom experienced its driest first half of summer (June 1 to July 16) on record. 

These images, acquired by our Terra satellite, show the burned landscape of the United Kingdom and northwestern Europe as of July 15, 2018, compared with July 17, 2017. 

Peter Gibson, a postdoctoral researcher at our Jet Propulsion Laboratory, examined how rising global temperatures are linked to regional heatwaves. “If the globe continues to warm, it’s clear we will continue to see events like this increasing in frequency, severity and duration,” Gibson said. “We found that parts of Europe and North America could experience an extra 10 to 15 heatwave days per degree of global warming beyond what we have seen already.”

Read more HERE.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com 

Why Won’t Our Parker Solar Probe Melt?

This summer, our Parker Solar Probe will launch to travel closer to the Sun than any mission before it, right into the Sun’s outer atmosphere, the corona.

The environment in the corona is unimaginably hot: The spacecraft will travel through material with temperatures greater than 3 million degrees Fahrenheit. 

So…why won’t it melt? 

The Difference Between Heat and Temperature

Parker Solar Probe was designed from the ground up to keep its instruments safe and cool, but the nature of the corona itself also helps. The key lies in the difference between heat and temperature.

Temperature measures how fast particles are moving, while heat is the total amount of energy that they transfer. The corona is an incredibly thin and tenuous part of the Sun, and there are very few particles there to transfer energy – so while the particles are moving fast (high temperature), they don't actually transfer much energy to the spacecraft (low heat).

It's like the difference between putting your hand in a hot oven versus putting it in a pot of boiling water (don’t try this at home!). In the air of the oven, your hand doesn't get nearly as hot as it would in the much denser water of the boiling pot. 

So even though Parker Solar Probe travels through a region with temperatures of several million degrees, the surface of its heat shield will reach only about 2,500 F.

The Heat Shield

Of course, thousands of degrees Fahrenheit is still way too hot for scientific instruments. (For comparison, lava from volcano eruptions can be anywhere between 1,300 to 2,200 F.) 

To withstand that heat, Parker Solar Probe is outfitted with a cutting-edge heat shield, called the Thermal Protection System. This heat shield is made of a carbon composite foam sandwiched between two carbon plates. The Sun-facing side is covered with a specially-developed white ceramic coating, applied as a plasma spray, to reflect as much heat as possible.

The heat shield is so good at its job that even though the Sun-facing side of the shield will be at 2,500 F, the instruments in its shadow will remain at a balmy 85 F.

Parker Solar Probe Keeps its Cool

Several other designs on the spacecraft help Parker Solar Probe beat the heat. 

Parker Solar Probe is not only studying the Sun – it's also powered by it. But even though most of the surface area of its solar arrays can be retracted behind the heat shield, even that small exposed segment would quickly make them overheat while at the Sun.  

To keep things cool, Parker Solar Probe circulates a single gallon of water through its solar arrays. The water absorbs heat as it passes behind the arrays, then radiates that heat out into space as it flows into the spacecraft's radiator. 

It's also important for Parker Solar Probe to be able to think on its feet, since it takes about eight minutes for information to travel between Earth and the Sun. If we had to control the spacecraft from Earth, by the time we knew something went wrong, it would be too late to fix it. 

So Parker Solar Probe is smart: Along the edges of the heat shield's shadow are seven sensors. If any of these sensors detect sunlight, they alert the central computer and the spacecraft can correct its position to keep the sensors – and the rest of the instruments – safely protected behind the heat shield.

Over the course of its seven-year mission, Parker Solar Probe will make 24 orbits of our star. On each close approach to the Sun, it will sample the solar wind, study the Sun’s corona, and provide unprecedentedly close up observations from around our star – and armed with its slew of innovative technologies, we know it will keep its cool the whole time. 

Parker Solar Probe launches summer 2018 on its mission to study the Sun. Keep up with the latest on the mission at nasa.gov/solarprobe or follow us on Twitter and Facebook.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com

2017 Was One of Our Planet’s Hottest Years on Record

We just finished the second hottest year on Earth since global temperature estimates first became feasible in 1880. Although 2016 still holds the record for the warmest year, 2017 came in a close second, with average temperatures 1.6 degrees Fahrenheit higher than the mean.

2017’s temperature record is especially noteworthy, because we didn’t have an El Niño this year. Often, the two go hand-in-hand.

El Niño is a climate phenomenon that causes warming of the tropical Pacific Ocean waters, which affect wind and weather patterns around the world, usually resulting in warmer temperatures globally. 2017 was the warmest year on record without an El Niño.

We collect the temperature data from 6,300 weather stations and ship- and buoy-based observations around the world, and then analyze it on a monthly and yearly basis. Researchers at the National Oceanic and Atmospheric Administration (NOAA) do a similar analysis; we’ve been working together on temperature analyses for more than 30 years. Their analysis of this year’s temperature data tracks closely with ours.

The 2017 temperature record is an average from around the globe, so different places on Earth experienced different amounts of warming. NOAA found that the United States, for instance, had its third hottest year on record, and many places still experienced cold winter weather.

Other parts of the world experienced abnormally high temperatures throughout the year. Earth’s Arctic regions are warming at roughly twice the rate of the rest of the planet, which brings consequences like melting polar ice and rising sea levels.

Increasing global temperatures are the result of human activity, specifically the release of greenhouse gases like carbon dioxide and methane. The gases trap heat inside the atmosphere, raising temperatures around the globe.  

We combine data from our fleet of spacecraft with measurements taken on the ground and in the air to continue to understand how our climate is changing. We share this important data with partners and institutions across the U.S. and around the world to prepare and protect our home planet.

Earth’s long-term warming trend can be seen in this visualization of NASA’s global temperature record, which shows how the planet’s temperatures are changing over time, compared to a baseline average from 1951 to 1980.

Learn more about the 2017 Global Temperature Report HERE. 

Discover the ways that we are constantly monitoring our home planet HERE. 

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.