The Sun in April – Steady as she goes!

The monthly updated graph for April of the Sun’s solar cycle sunspot activity was posted yesterday by NOAA’s Space Weather Prediction Center. You can see it below.

Though the Sun remained active, you can see that the steep increase in sunspot activity that occurred in March has ceased. At the moment it looks as if the Sun’s sunspot activity is following the most recent scientific prediction, more or less exactly, though the small dip in April puts the numbers slightly below that prediction.

All in all, we still appear to be headed to the weakest solar maximum in two hundred years.

April Sunspot activity

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More info on the asteroid “flyby” of Earth this coming November 8

More information on the asteroid “flyby” of Earth this coming November 8.

“On November 8, asteroid 2005 YU55 will fly past Earth and at its closest approach point will be about 325,000 kilometers [201,700 miles] away,” said Don Yeomans, manager of NASA’s Near-Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, Calif. “This asteroid is about 400 meters [1,300 feet] wide – the largest space rock we have identified that will come this close until 2028.”

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Are astronomers finally going to push for a replacement for Hubble?

Astronomers are considering the merger two space missions to create a new optical/ultraviolet space telescope. The mission would be designed to do both deep cosmology and exoplanet observations.

The two communities would both like to see a 4–8-metre telescope in space that would cost in excess of $5 billion. “Our interests are basically aligned,” says [Jim Kasting, a planetary scientist at Pennsylvania State University]. Such a mission would compete for top billing in the next decadal survey of astronomy by the US National Academy of Sciences, due in 2020.

This story is big news, as it indicates two things. First, the 2010 Decadal Survey, released in August 2010, is almost certainly a bust. The budget problems at NASA as well as a general lack of enthusiasm among astronomers and the public for its recommendations mean that the big space missions it proposed will almost certainly not be built.
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Japan’s tsunami waves top historic heights

Japan’s tsunami in March produced the largest waves in history.

Some waves grew to more than 100 feet high, breaking historic records, as they squeezed between fingers of land surrounding port towns.

To me, however, this is the biggest takeaway:

Although terrible, the preliminary estimate also finds a better-than 92% survival rate for people living in coastal towns hit by the waves, Bourgeois says. “In that sense, given the magnitude of the unexpectedly large earthquake, things could have been even worse,” she says.

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Observations of Comet Hale-Bopp at 30 AU

In a paper published tonight on the Los Alamos astro-ph preprint website, astronomers described new observations of Comet Hale-Bopp at a distance of 30 astronomical units, or 2.8 billion miles, from the sun. Their conclusions:

  • These observations were the most distant detection of any known comet.
  • The comet’s starlike appearance and its drop in brightness since the last observations suggest that the comet has finally ceased, or is about to cease, all activity, and that they are now looking directly at the comet’s nucleus instead of the coma cloud surrounding it.
  • Nonetheless, the comet is brighter than expected, which also suggests that a thin layer of new ice covers its surface and thus increases its albedo.

To quote the paper, “Observing Hale-Bopp in a completely frozen state would be extremely important because a thick coma was constantly present during the entire appariation [Ed. the fly-by of the Sun]. The coma obscured the nucleus which was not observed directly. Lack photometric data of the bared nucleus, its size — one of the most important input parameter in activity models — remains uncertain.”

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