<p style="margin: 5pt 0pt;">Absinthe-green <a id="mt8c" title="Auroras" href="http://science.nationalgeographic.com/science/space/universe/auroras-heavenly-lights.html">Auroras</a> course across the Yukon sky in a picture featured March 11 on NASA's <a id="n74z" title="Astronomy Photo of the Day" href="http://antwrp.gsfc.nasa.gov/apod/ap100311.html">Astronomy Photo of the Day</a> site. Captured around dawn on March 11 near Dawson City, Canada, the image is a digital combination of several exposures, which allowed both the northern lights and the paths of stars—which appear to be moving due to Earth's rotation—to shine.</p><p style="margin: 5pt 0pt;">With the vernal equinox, or spring equinox, arriving on Saturday, northern lights should be in abundance this week. For reasons that remain a mystery, the sky shows tend to proliferate around the first day of spring, <a id="oe3y" title="according to NASA" href="http://science.nasa.gov/headlines/y2008/20mar_spring.htm">according to NASA</a>.</p><p style="margin: 5pt 0pt;">Auroras occur as particles from the sun speed toward Earth and become energized as they encounter with the planet's magnetic field lines. As the powered-up particles smash into oxygen and nitrogen in our atmosphere, the particles release their energy as red, green, and blue light. (See <a href="http://photography.nationalgeographic.com/photography/photos/patterns-nature-northern-lights.html">aurora pictures</a>.)</p><p style="margin: 5pt 0pt;">(Related: <a id="wn1b" title="&quot;Giant &amp;squot;Space Tornadoes&amp;squot; Spark Auroras on Earth.&quot;" href="http://news.nationalgeographic.com/news/2009/04/090424-space-tornadoes-auroras.html">"Giant 'Space Tornadoes' Spark Auroras on Earth."</a>)</p>

Dawn of Aurora Season

Absinthe-green Auroras course across the Yukon sky in a picture featured March 11 on NASA's Astronomy Photo of the Day site. Captured around dawn on March 11 near Dawson City, Canada, the image is a digital combination of several exposures, which allowed both the northern lights and the paths of stars—which appear to be moving due to Earth's rotation—to shine.

With the vernal equinox, or spring equinox, arriving on Saturday, northern lights should be in abundance this week. For reasons that remain a mystery, the sky shows tend to proliferate around the first day of spring, according to NASA.

Auroras occur as particles from the sun speed toward Earth and become energized as they encounter with the planet's magnetic field lines. As the powered-up particles smash into oxygen and nitrogen in our atmosphere, the particles release their energy as red, green, and blue light. (See aurora pictures.)

(Related: "Giant 'Space Tornadoes' Spark Auroras on Earth.")

Image by Yuichi Takasaka, TWAN

Space Photos This Week: Spring Auroras, Starlets, More

Auroras spring to life, the Milky Way enters middle age, a Mars moon gets its close-up, and more in the week's best space pictures.

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