Did you know that several forest species need fire to survive?
In the conifer-rich forests of western North America, lodgepole pines constantly seek the sun. Their seeds prefer to grow on open, sunny ground, which pits saplings against each other as each tries to get more light by growing straighter and faster than its neighbors. Over time, generations of slender, lofty lodgepoles form an umbrella-like canopy that shades the forest floor below. But as the trees’ pine cones mature to release their twirling seeds, this signals a problem for the lodgepole’s future: very few of these seeds will germinate in the cool, sunless shade created by their towering parents.
These trees have adapted to this problem by growing two types of cones. There are the regular annual cones that release seeds spontaneously:
And another type called serotinous cones, which need an environmental trigger to free their seeds:
Serotinous cones are produced in thousands and are like waterproof time capsules sealed with resinous pitch. Many are able to stay undamaged on the tree for decades. Cones that fall to the ground can be viable for several years as well. But when temperatures get high enough, the cones pop open.
Once it’s gotten started, a coniferous forest fire typically spreads something like this: flames ravage the thick understory provided by species like Douglas Fir, a shade-tolerant tree that’s able to thrive under the canopy of lodgepole pines. The fire uses these smaller trees as a stepladder to reach the higher canopy of old lodgepole pines. That ignites a tremendous crown fire, reaching temperatures of up to 2400 degrees Fahrenheit. At those temperatures, the serotinous cones burst open, releasing millions of seeds which are carried by the hot air to form new forests. After the fire, carbon rich soils and an open, sunlit landscape help lodgepole seeds germinate quickly and sprout in abundance. From the death of the old forest comes the birth of the new.
So however counterintuitive it may seem, wildfires are important for the wider ecosystem as a whole. Without wildfires to rejuvenate trees, key forest species would disappear—and so would the many creatures that depend on them. And if a fire-dependent forest goes too long without burning, that raises the risk of a catastrophic blaze which could destroy a forest completely, not to mention people’s homes and lives. That’s why forest rangers sometimes intentionally start controlled burns—to reduce fuels in order to keep the more dangerous wildfires at bay.
From the TED-Ed Lesson Why wildfires are necessary - Jim Schulz
Animation by @provinciastudio
Scientists from Chalmers University of Technology have been able to extend the lifetime of an artificial atom, allowing it to remain charged for up to ten times longer. They achieved this by placing the artificial atom in front of a short circuit, which acts as a mirror. The distance between the atom and the mirror affects how long the atom “lives,” which is the time from when an atom is charged to when it returns to its ground state.
Research team leader and Professor of Physics Per Delsing says, “We can vary the lifetime of the atom by changing the distance between the atom and the mirror. If we place the atom at a certain distance from the mirror the atom’s lifetime is extended by such a length that we are not even able to observe the atom.”
Know more at: http://futurism.com/links/scientists-extend-an-atoms-lifetime-with-a-mirror/
Why the Brain Makes Mistakes
A study conducted at Carnegie Mellon University investigated the brain’s neural activity during learned behavior and found that the brain makes mistakes because it applies incorrect inner beliefs, or internal models, about how the world works. The research suggests that when the brain makes a mistake, it actually thinks that it is making the correct decision—its neural signals are consistent with its inner beliefs, but not with what is happening in the real world.
The research is in eLife. (full access paywall)
Area of a circle
Interactive version:
http://www.malinc.se/math/geometry/circleen.php
It often seems so quiet after a snowfall because the fresh powder absorbs sound waves. As the snow melts and freezes, it then creates a reflective surface that allows sound to travel farther than normal. Source
Our solar system is huge, let us break it down for you. Here are a few things you should know this week:
1. Closeup of a King
For the first time since it entered orbit around Jupiter in July, our Juno spacecraft has flown close to the king of planets—this time with its eyes wide open. During the long, initial orbit, Juno mission managers spent time checking out the spacecraft “from stem to stern,” but the science instruments were turned off as a precaution. During this latest pass, Juno’s camera and other instruments were collecting data the whole time. Initial reports show that all went well, and the team has released a new close-up view that Juno captured of Jupiter’s north polar region. We can expect to see more close-up pictures of Jupiter and other data this week.
+Check in with Juno
2. Getting Ready to Rocket
Our OSIRIS-REx mission leaves Earth next week, the first leg of a journey that will take it out to an asteroid called Bennu. The mission will map the asteroid, study its properties in detail, then collect a physical sample to send back home to Earth. The ambitious endeavor is slated to start off on Sept. 8.
+See what it takes to prep for a deep space launch
3. New Moon Rising
The Lunar Reconnaissance Orbiter (LRO) has already mapped the entire surface of Earth’s moon in brilliant detail, but the mission isn’t over yet. Lunar explorers still have questions, and LRO is poised to help answer them.
+See what’s next for the mission
4. A Mock-Eclipse Now
We don’t have to wait until next year to see the moon cross in front of the sun. From its vantage point in deep space, our Solar Dynamics Observatory (SDO) sometimes sees just that. Such an event is expected on Sept. 1.
+See the latest sun pictures from SDO
5. Jupiter’s Cousins
Our galaxy is home to a bewildering variety of Jupiter-like worlds: hot ones, cold ones, giant versions of our own giant, pint-sized pretenders only half as big around. Astronomers say that in our galaxy alone, a billion or more such Jupiter-like worlds could be orbiting stars other than our sun. And we can use them to gain a better understanding of our solar system and our galactic environment, including the prospects for finding life.
Want to learn more? Read our full list of the 10 things to know this week about the solar system HERE.
Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com
Researchers at the Massachusetts Institute of Technology want to change how we connect to Wi-Fi. To avoid the cumbersome network login process, a team has come up with a way to grant computers access to a Wi-Fi network based on their proximity to a router. But what about security?
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