Sky-watchers took to Twitter today to share their experiences watching the solar eclipse, which was visible from Australia and parts of the Pacific.
Tweeted @xoxoalbertxoxo: "Instead of studying for my AP tomorrow, I'm just gonna watch the #SolarEclipse tonight." Advised @Pandabattlemode, "Something awesome is happening BUT DON'T LOOK AT IT. EVER."
Others found the eclipse obscured from their vantage point. "It seems there's no #SolarEclipse today, clouds are blocking the sun. How am i suppose to see that stuff?" tweeted @KarlAlocada. Noted @PaoloAnota: "5:56AM—The sun sneaks thru a break in the cloud formation."
The "ring of fire" will darken skies on Thursday as the black silhouette of the moon appears to glide across the face of the sun until only a bit of sunlight is visible. (See annular eclipse pictures.)
Though the celestial phenomenon will be visible mostly in remote areas in the Pacific, armchair astronomers can watch a live feed of the eclipse, thanks to the Coca Cola Space Science Center.
The Georgia-based center will webcast the annular eclipse via a telescope from Cape York, Australia, starting on May 9 at 5 p.m. ET (21:00 UT). (See a list of cities and times along the path of the eclipse, and find out when the eclipse will occur in your time zone.)
"It is always astonishing to see the moon apparently cut bites out of the sun," said eclipse expert Jay Pasachoff, Field Memorial Professor at Williams College in Massachusetts and a National Geographic explorer. (Related: "Eclipse Expert Makes Hot Finds in Sun's Darkest Hour.")
"And it is a wonder of modern science and mathematics that you can travel halfway around the world, arriving on a normal day with blue sky, but then, on schedule, the lunar silhouette breaks up the sunlight."
What is an annular eclipse?
A solar eclipse occurs when the Earth, moon, and sun line up so that the moon's shadow is cast on the Earth. (Video: Sun 101.)
A total solar eclipse occurs when the sun's entire disk is covered by the moon.
During an annular eclipse, the new moon's apparent diameter is smaller than the visible disk of the sun, making the covered sun appear for a few minutes as a striking annulus (ring)—otherwise known as the ring of fire. (Also see "'Ring of Fire' Solar Eclipse Coming Sunday .")
Why do we get two kinds of solar eclipses?
Two types of solar eclipses—total and annular—occur because the moon's path around the Earth is egg-shaped, so over a course of the moon's one-month orbit, its distance to our planet can vary. For sky-watchers, this means that the moon's apparent diameter in the sky will change too.
If the moon is near its farthest point from Earth during a solar eclipse, it will appear to sky-watchers to be smaller than the sun's disk, allowing a ring of sunlight to peek out around the moon. (Also see "Solar Eclipses Can [Slightly] Change Weather on Earth.")
However, if the moon happens to be at its closest point to Earth during a solar eclipse, it will appear to cover the sun completely.
Who will see Thursday's ring of fire?
The 140-mile-wide (225-kilometer-wide) track of the moon's shadow starts in western Australia on Friday morning, May 10, at 6:32 a.m. local time, goes over Australia's Northern Territories and Queensland, and sweeps across to Cape York Peninsula (map) at 8:44 a.m. local time.
The shadow reaches the eastern shores of Papua New Guinea at 9 a.m. local time and then races across the Pacific Ocean, making its last major landfall on the Solomon Islands at 10:15 a.m. local time.
Unfortunately for most avid sky-watchers, the full shadow path cuts across some of the more remote and unpopulated areas of the Pacific region.
"The only other land in the path of annularity is the Pacific Island group of Kiribati," said Pasachoff.
For most viewers who can see the event, the eclipse will last three to five minutes.
Where will the partial eclipse be visible?
Partial phases of the eclipse—where only a percentage of the sun is covered by the lunar disk—will be visible across a much wider area, including Australia, New Zealand, the Philippines, Indonesia, and Hawaii.
While the entire event will be invisible for all of mainland U.S., a partial eclipse will be visible for observers in Honolulu, Hawaii, with up to 44 percent of the sun covered at 3:48 p.m. local time (1:48 UT on May 10).
How best to watch this event?
For observers along the path of the eclipse, astronomers recommend using either a professionally manufactured solar filter in front of a telescope or camera, or eclipse-viewing glasses that sufficiently reduce the sun's brightness and filter out damaging ultraviolet and infrared radiation. (Check out a DIY alternative: Build an eclipse viewer).
What if I miss this one?
The next solar eclipse will occur on November 3, with the shadow path crossing the open Atlantic Ocean and central parts of Africa.