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In Space, Flames Behave in Ways Nobody Thought Possible

Recent tests aboard the International Space Station have shown that fire in space can be less predictable and potentially more lethal than it is on Earth. “There have been experiments,” says NASA aerospace engineer Dan Dietrich, “where we observed fires that we didn’t think could exist, but did.”

Image: A composite false-color image of fire in space. The bright yellow traces the path of a drop of fuel, shrinking as it burns, producing green soot Credit: Paul Ferkul / NASA

That fire continues to surprise us is itself surprising when you consider that combustion is likely humanity’s oldest chemistry experiment, consisting of just three basic ingredients: oxygen, heat and fuel.

Here on Earth, when a flame burns, it heats the surrounding atmosphere, causing the air to expand and become less dense. The pull of gravity draws colder, denser air down to the base of the flame, displacing the hot air, which rises. This convection process feeds fresh oxygen to the fire, which burns until it runs out of fuel. The upward flow of air is what gives a flame its teardrop shape and causes it to flicker.

But odd things happen in space, where gravity loses its grip on solids, liquids and gases. Without gravity, hot air expands but doesn’t move upward. The flame persists because of the diffusion of oxygen, with random oxygen molecules drifting into the fire. Absent the upward flow of hot air, fires in microgravity are dome-shaped or spherical—and sluggish, thanks to meager oxygen flow. “If you ignite a piece of paper in microgravity, the fire will just slowly creep along from one end to the other,” says Dietrich. “Astronauts are all very excited to do our experiments because space fires really do look quite alien.”

Such fires might appear eerily tranquil to people accustomed to the capricious nature of earthly flames. But a flame in microgravity can be more tenacious, capable of surviving on less oxygen and burning for longer periods of time.

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Fires and Stars

From the photographer: “During the night of August 14, 2012, the mountains on the west side of Southern California’s Anza-Borrego Desert erupted with a series of massive and rapidly moving wildfires known as the Vallecito Lightning Complex. Though the glow and smoke were visible to all around the Borrego Valley , so too were the glistening stars overhead.” —Dennis Mammana

Star Fire

fyeahuniverse:

Blazing Fires In The US Caught By NASA’s Aqua Satellite

Just as the AIRS instrument on Aqua can detect the ambient temperature of clouds, the MODIS infrared imaging instrument can detect hot-spots on land. When Aqua takes an image, it highlights the hot spots in red and smoke clouds in light brown.

Image credit: NASA Goddard MODIS Rapid Response Team, Jeff Schmaltz

Experiment Investigates How to Fight Fire in Space

Image: Color image of a fuel droplet burning in space during NASA’s Flame Extinguishment Experiment aboard the International Space Station. Credit: NASA/GRC

New experiments on the International Space Station may reveal tips on fighting fires in space, and back here on Earth, too.

In space, where there is no up or down, and the atmosphere and pressure within the closed confines of a spacecraft are tightly controlled, fire burns differently. The Flame Extinguishment Experiment, known as FLEX, aims to better understand how.

For example, in the weightless environment of orbit, flames can burn at a lower temperature and require less oxygen to ignite than they do in normal gravity. Thus, fire extinguishers in space must use more-concentrated material.

Another difference is that a flame around a droplet of fuel in space can be completely spherical, while that is very different to achieve on the ground. And this spherical symmetry makes it easier to observe droplets’ behavior and to craft the calculations that explain it, the study’s leader, University of California, San Diego, aerospace engineering professor Forman Williams, said in a statement.

jtotheizzoe:

What is Gravity?

I can think of no better way to answer this question than fire and a trebuchet. Thank you, BBC.

(by BBC)

comicartappreciation:

Fire & Ice // Adam Hughes

Forest Fire and Milky Way

Copyright: Phil Jones

Aflame

Fire acts differently in space than on Earth. Sandra Olson, an aerospace engineer at NASA’s Glenn Research Center, demonstrates just how differently in her art. This artwork is comprised of multiple overlays of three separate microgravity flame images. Each image is of flame spread over cellulose paper in a spacecraft ventilation flow in microgravity. The different colors represent different chemical reactions within the flame. The blue areas are caused by chemiluminescence (light produced by a chemical reaction.) The white, yellow and orange regions are due to glowing soot within the flame zone.

Microgravity combustion research at Glenn not only provides insights into spacecraft fire safety, but it has also been used to create award-winning art images. This image won first place in the 2011 Combustion Art Competition, held at the 7th U.S. National Combustion Meeting.

Image Credit: NASA

Forest Fire and Milky Way

Copyright: Phil Jones

sciencecenter:

Global warming could scorch the Western US

“If climate change drives temperature up a degree or two,” goes the common dismissal, “how bad could that be?”

Here’s an example: Higher temperatures draw moisture out of live and dead trees and brush, making them more flammable. The heat also can alter precipitation, as well as shift spring thaw earlier, lengthening the fire season. A one degree Celsius climb in average global temperature could cause the median area burned annually by wildfires in parts of the American West to increase up to sixfold. “A one-degree rise could occur well before 2050,” notes Jeremy Littell, a climate and fire researcher at the University of Washington, who created the projections with the U.S. Forest Service and other institutions.

Scientists in Canada have reached similar conclusions about their western region. The U.S. prediction applies to area burned during median fire years; extreme fire years would consume still more area. Unfortunately, as temperature goes up, Littell predicts, “what were historically big fire years may become more frequent.”

The Milky Way Over the Peak of the Furnace

On Reunion Island, it is known simply as “The Volcano.” To others, it is known as the Piton de la Fournaise, which is French for the Peak of the Furnace. It is one of the most active volcanoes in the world. The Volcano started a new eruption last month by spewing hot lava bombs as high as 10 meters into the air from several vents. Pictured above, the recent eruption was caught before a star filled southern sky, appearing somehow contained beneath the arching band of our Milky Way Galaxy. Also visible in the background sky is the Pleiades open star cluster, the constellation of Orion, the brightest star Sirius, and the neighboring Large and Small Magellanic Cloud galaxies. (Can you find them?) The Piton de la Fournaise erupted for months in 2006, and for days in 2007, 2008, and in January of 2010. Nobody knows how long the current eruption will last, or when The Volcano will erupt next.

Credit & Copyright: Luc Perrot