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WATCH LIVE @ 7:30 pm ET: Planet Definition Debate Tonight

Pluto Viewed From One of Its Moons
Artist's concept showing Pluto, center, and several of its five known moons, as viewed from the surface of one of the satellites.
CREDIT: NASA, ESA and G. Bacon (STScI)

If you're confused about what exactly a planet is, don't feel bad: Astronomers are still arguing over the term eight years after the International Astronomical Union (IAU) came up with a controversial new definition that demoted Pluto to "dwarf planet" status.

The Harvard-Smithsonian Center for Astrophysics (CfA) is putting on an event tonight (Sept. 18) at 7:30 p.m. EDT (2330 GMT) that could help crystallize your views. The event, which will be webcast live in the window below, is called "What Is a Planet?" and features three different experts presenting their viewpoints on the term, and on the ongoing debate.

Photos of Pluto and Its Moons

Pluto: A Dwarf Planet Oddity (Infographic)

Our Solar System: A Photo Tour of the Planets

REPLAY: Solar Storm Webcast, Sept. 11: To see our latest story on the solar storm effects on Earth last week, visit: Back-to-Back Sun Storms May Supercharge Earth's Northern Lights

The online Slooh Community Observatory will host a free webcast on Thursday, Sept. 11, to provide live views of the active sunspot AR2158, which unleashed a massive X1.6 solar flare on Wednesday (Sept. 10). The webcast will begin at 1 p.m. EDT (1700 GMT). You can watch it live on the Slooh website ( and in the window below:

X-class solar flares  are the most powerful type of storms on the sun. The Slooh  webcast will feature live views of AR2158 from a solar telescope at the Prescott Observatory in Prescott, Arizona. Slooh host Geoff Fox, astronomer Bob Berman and Prescott Observatory owner Matt Francis will provide live commentary during the webcast. Viewers can submit questions via Twitter using the hashtag #Sloohflare. Sun Unleashes Major Solar Flare at Earth

Powerful Solar X-Flare Pointed At Earth

"What solar experts fear most is a recurrence of the huge coronal mass ejection events of 1921 and 1859. A government­-sponsored panel in 2008 estimated that such a solar event today would likely destroy the U.S. electrical grid, inflict a staggering $1 to $2 trillion dollars worth of damage, and require over a year to repair," Berman said. "So it's more than of mere academic interest to monitor and observe these violent events as they unfold. Plus, they're amazing to watch."

Biggest Solar Flares of 2014: Sun Storm Photos

Solar Quiz: How Well Do You Know Our Sun?

Anatomy of Sun Storms & Solar Flares (Infographic )

The Sun's Wrath: Worst Solar Storms in History

Mid-Sized Solar Flare Blasts CME, Possibly Earth-Bound | Video

September Harvest Moon Replay

The Slooh Community Observatory will host a webcast featuring live views of the 2014 full Harvest Moon tonight (Sept. 8) at 9:30 p.m. EDT (0130 Sept. 9 GMT). The full moon that rises closest to the September equinox is deemed the Harvest Moon. This moon is also special because it is the third in a series of "supermoons" - full moons that rise when the moon is at its closest point to Earth in its orbit. You can watch the webcast from Slooh in the window below: 

You also can watch the Slooh webcast by following this link:

From Slooh: "Whether we call this a super Harvest Moon or a Harvest supermoon, and whether we fuss over the fact that lunar perigee happened just one night before this moon was full, there's no denying that it's the Harvest Moon," Slooh astronomer Bob Berman said in a statement. "This is the year's most famous full moon, and one of only two that even have a name. Yet it's bathed in myth and misconception even without all the extra 'supermoon' business. It will be fun to explore the true secrets of the Harvest Moon while watching it live."

Related Links

Replay: Slooh 'Supermoon' Webcast

The online Slooh Community Observatory will host a webcast about the supermoon on Sunday (Aug. 10) starting at 7:30 p.m. EDT (2330 GMT). Slooh representatives will discuss this month's full moon, the biggest of 2014. Latest StoryIs Sunday's Supermoon Full Moon Really That Super?  The moon is going to turn full phase at perigee - the point in its orbit when the natural satellite is closest to Earth. You can watch the webcast in the window below or directly through Slooh

"Nothing in the sky is more striking than the rising of an enormous-looking full moon," Slooh astronomer Bob Berman said in a statement. "And this will be largest since March, 2011. And although the size-enhancement is 11 percent compared to an apogee full moon like the the one this past January, it will seem even larger -- much larger -- thanks to the psycho-optical effect we will discuss during the show. And, thanks to the super-tides that day and the following day, Earth’s biosphere will definitely be affected by this event."

Related Links:

Webcast Replay

The online Slooh Community Observatory  offered live views of the annual Delta Aquarid meteor shower on Monday night (July 28) and you can relive the webcast live via and here on this page. The webcast, which will be followed Tuesday by a NASA meteor webcast, will begin at 10 p.m. ET (7 p.m. PT/0200 GMT) and feature commentary from Slooh experts. Full Story: Don't Miss These Minor Meteor Showers This Summer

The Slooh Community Observatory webcast will feature a live video stream of the peak of the Delta Aquarids from the Institute of Astrophysics, Canary Islands and the Prescott Observatory in Arizona. Slooh astronomer Bob Berman will provide audio commentary during the event. Viewers can also follow the meteor shower webcast on Twitter with the hashtag #SloohShower.

Slooh will be using a new super-sensitive low-light equipment to enhance its meteor views from the Canary Islands, courtesy of the Prescott Observatory, Slooh representatives said in a statement.

"The results obtained by this new equipment are what's primarily fascinating," Berman said. "We're hoping to capture more meteors than ever before, despite the modest nature of this relatively little­-known shower."

Berman said that the origins of the Delta Aquarid meteor shower thought to be the Comet Macholtz, which was discovered in 1986, but it is not known for sure. "The slightly mysterious nature of these often-­overlooked shooting stars adds to the night's fun."

Replay: Full Moon on Friday the 13th

Friday the 13th coincides with a full moon but you don't have to wait to see amazing views of the full moon. The online Slooh community telescope will provide live views of the moon June 12 at 9:30 p.m. EDT. Watch live here. 

From Slooh

"Slooh will cover the Honey Moon live on Thursday, June 12th starting at 6:30 PM PDT / 9:30 PM EDT / 01:30 UTC (6/13) ­ International Times: Slooh will broadcast the event live for two hours from Slooh member controlled observatory sites: (1) off the west coast of Africa, at the Institute of Astrophysics of the Canary Islands, and (2) the Pontificia Universidad Católica De Chile (PUC) near Santiago, Chile. Viewers can watch the full Honey Moon broadcast free on The image stream will be accompanied by discussions led by Slooh host, Geoff Fox, Slooh astronomer, Bob Berman, and Slooh Observatory Engineer, Paul Cox, who will be reporting in live at Slooh’s Canary Islands observatory. Viewers can follow updates on the show by using the hashtag #Sloohhoneymoon."

More resources: 

The Moon: 10 Surprising Lunar Facts

Full Moon: Why Does It Happen? How Does It Affect Us?

Moon Master: An Easy Quiz for Lunatics

Beast Asteroid Replay

The online Slooh community observatory will hold a free webcast today (June 5) at 2:30 p.m. EDT (1830 GMT) to showcase the newfound asteroid 2014 HQ124, which is 1,100 feet wide and will pass safely by Earth on Sunday, June 8. You can watch the webcast live on and in the window below here. FULL STORY HERE: Huge 'Beast' Asteroid to Fly By Earth Soon, Live Webcast Today: Video

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