First Look: ISON Approaches by Adam Block

Scientists are unraveling more information on Comet C/2012 S1 (ISON) as it continues on its journey toward the sun.

Comet C/ISON will skim 730,000 miles above the sun’s surface on Nov. 28 and has the potential to be readily visible from Earth starting in early December.

“We measured the rotational pole of the nucleus. The pole indicates that only one side of the comet is being heated by the sun on its way in until approximately one week before it reaches it closest point to the sun,” said Planetary Science Institute Research Scientist Jian-Yang Li, who led a team that imaged the comet.

“Since the surface on the dark side of the comet should still retain a large fraction of very volatile materials, the sudden exposure to the strong sunlight when it gets closer to the sun than Mercury could trigger huge outbursts of material,” Li said.

Li presented the findings today at the American Astronomical Society’s Division for Planetary Sciences 45th Annual Meeting in Denver.

Via (Comet ISON details emerge as it races toward the sun)


“Sungrazing” is an oxymoron
In spite of hopes and fantasy.
Nothing survives the touch of the Sun
(Save few like the Kreutz family).
Yet it is inexorable and fair
For comets’ deadly attempts.
Destined to keep on going,
They’re the Great Star’s contempt.
Like many have done before,
This mass of ice and dust
Ventured close to the Fire,
Bracing itself as it must,
‘Twas only around the corner,
The jubilation of the brilliance,
Endurance would keep it together
As it approached perihelion.
Wishing to mean something—
The comet of the century—
Not knowing that the Grace
Burns anything in its territory.
Like most other sungrazers,
It was defeated and gone,
Not a single trail left behind
To inspire with the coming of dawn.


Sungrazer’s “If”

This song has burned a hole in my head.

Comet Ison ‘May Have Survived’ Brush With Sun

Astronomers tracking what they hoped would be the “comet of the century” say some of it may have survived its close encounter with the Sun.

It was first reported that the Comet Ison’s nucleus and tail had been destroyed by the Sun’s radiation and tidal forces but the European Space Agency (ESA) said the “story continues”.

The latest pictures appear to show a brightening of a chunk of the comet which has caused a surge in excitement among skygazers.

It is hard to know what has happened but experts say dust and gas are being released and the tail may be growing back.

If it is visible in the night sky, it is too soon to know how bright it will be or how long it will last.

Comet Ison, which had been hurtling through space at speeds of 845,000mph, was due to pass within 730,000 miles of the surface of the star last night.

It was expected to be met with temperatures of about 2,700C (4,892F) and an intense gravitational pull as it prepared for its solar slingshot.

Full Article



Some Comets Like It Hot

Video description:

Astronomers are still scratching their heads over Comet Lovejoy, which plunged through the atmosphere of the sun in December and, against all odds, survived. The comet is now receding into the outer solar system leaving many mysteries behind.

Video by NASA

Video transcript:

Some Comets Like it Hot.

Presented by Science at NASA.

Comets are icy and fragile.

They spend most of their time orbiting through the dark outskirts of the solar system safe from the withering depredations of intense sunlight.

Their natural habitat is the deepest cold.

Last November amateur astronomer Terry Lovejoy discovered a different kind of comet.

The icy fuzzball he spotted in the sky over his backyard observatory in Australia was heading almost directly for the sun.

On December 16th, less than three weeks after he found it, Comet Lovejoy would swoop through the sun’s atmosphere only 120,000 km above the stellar surface.

Astronomers would soon realize a startling fact: Comet Lovejoy likes it hot.

“Terry found a sungrazer,” says Karl Battams of the Naval Research Lab in Washington DC. “It appeared to be as wide as two football fields the biggest such comet in nearly 40 years.”

Sungrazing comets aren’t a new thing.

In fact, the orbiting Solar and Heliospheric Observatory (SOHO) watches one fall toward the sun and evaporate every few days.

These frequent “kamikaze comets” are thought to be splinters of a giant comet that broke apart hundreds of years ago.

Typically they measure about 10 meters across, small, fragile, and easily vaporized by solar heat.

Based on its orbit, Comet Lovejoy was surely a member of the same family, except it was 200 meters wide instead of the usual 10.

Astronomers were eager to see such a whopper disintegrate.

There was little doubt that it would be destroyed.

When December 16th came, however, “Comet Lovejoy shocked us all,” says Battams. “It survived, and even flourished.”

Images from NASA’s Solar Dynamics Observatory showed the comet vaporizing furiously as it entered the sun’s atmosphere, apparently on the verge of obliteration yet

Comet Lovejoy was still intact when it emerged on the other side. The comet had lost its tail during the fiery transit, a temporary setback.

Within hours, the tail grew back, bigger and brighter than before.

“It’s fair to say we were dumbfounded,” says Matthew Knight of the Lowell Observatory and the Johns Hopkins Applied Physics Lab.

“Comet Lovejoy must have been much bigger and tougher than we thought.”

Only a few days after it left the sun, the comet showed up in the morning skies of the southern hemisphere.

Observers in Australia, South America, and New Zealand likened it to a search light beaming up from the east before dawn.

The tail lined up parallel to the Milky Way and, for a few days, made it seem that we lived in a double-decker galaxy.

Astronauts on the International Space Station also witnessed the comet.

ISS Commander Dan Burbank, who has seen his share of wonders, even once flying directly through the Northern Lights onboard the space shuttle, declared Comet Lovejoy “the most amazing thing I have ever seen in space.”

An armada of spacecraft including SOHO, the Solar Dynamics Observatory (SDO), NASA’s twin Solar Terrestrial Relations Observatory (STEREO) probes, Japan’s Hinode spacecraft, and

Europe’s Proba2 microsatellite recorded the historic event. “We’ve collected a mountain of data,” says Knight. “But there are some things we’re still having trouble explaining.”

For instance, what made Lovejoy’s tail wiggle so wildly when it entered the solar corona?

Perhaps it was in the grip of the sun’s powerful magnetic field.

What caused Lovejoy to lose its tail inside the sun’s atmosphere, and then regain it later?

“This is one of the biggest mysteries to me,” says Battams.

And then there is the ultimate existential puzzle: How did Comet Lovejoy survive at all?

The “Comet that liked it Hot” is returning to the outer solar system, apparently still intact, leaving many mysteries behind.

“It’ll be back in about 600 years,” says Knight. “Maybe we will have figured them out by then.”

To learn about more Solar System mysteries hot and cold visit

First-Ever Observations of Comet’s Demise Inside Solar Atmosphere

Image: C/2007 Lulin N3

In a paper to be published tomorrow in the journal Science, for the first time ever scientists at the Lockheed Martin Solar and Astrophysics Laboratory (LMSAL) at the Advanced Technology Center (ATC) in Palo Alto, and collaborators at other institutions, have reported observations and analysis of the final death throes of a comet, as it passed across the face of the Sun on July 6, 2011, to vanish in flight.

Using observations from the Atmospheric Imaging Assembly (AIA) instrument on board NASA’s Solar Dynamics Observatory (SDO), the comet was first seen about 0.2 solar radii off the limb of the Sun, travelling at nearly 400 miles per second and was tracked for 20 minutes until it disintegrated and evaporated in the low solar corona, about 62,000 miles above the solar surface.

The Extreme-Ultraviolet Imager (EUVI), on one of NASA’s twin Solar-Terrestrial Relations Observatories (STEREO), made simultaneous additional observations of the comet’s passage from its near-quadrature view relative to the Sun-Earth line.

The comet was discovered on July 4, 2011 by using the Large Angle and Spectrometric Coronagraph (LASCO) on the ESA/NASA Solar and Heliospheric Observatory (SOHO), and was designated comet C/2011 N3 (SOHO). It was the SOHO discovery that alerted Lockheed Martin scientists to watch the AIA data stream for the comet’s likely transit across the face of the Sun.

A small comet plunged into the sun on August 20th. Just before it arrived, the sun expelled a magnificent full-halo CME.

In the final frames of the movie, the comet can be seen furiously vaporizing. Indeed, those were the comet’s final frames. It did not emerge again from its flyby of the hot sun. “With a diameter of perhaps a few tens of meters, this comet was clearly far too small to survive the intense bombardment of solar radiation,” comments Karl Battams of the Naval Research Lab, who studies sungrazing comets.

The CME (coronal mass ejection) came from an explosion on the farside of the sun. Although the CME and the comet appear to intersect, there was probably no interaction between the two. The comet is in the foreground and the farside CME is behind it.

Occasionally, readers ask if sundiving comets can trigger solar explosions. There’s no known mechanism for comets to spark solar flares. Comets are thought to be too small and fragile to destabilize the sun’s magnetic field. Plus, this comet was still millions of kilometers from the sun when the explosion unfolded.

The comet, R.I.P., was a member of the Kreutz family. Kreutz sungrazers are fragments from the breakup of a single giant comet many centuries ago. They get their name from 19th century German astronomer Heinrich Kreutz, who studied them in detail. Several Kreutz fragments pass by the sun and disintegrate every day. Most, measuring less than a few meters across, are too small to see, but occasionally a bigger fragment like this one attracts attention.

As Earth passes through the wake of one CME, which did little to stir geomagnetic activity on Aug. 20th, another CME is on the way. NOAA forecasters expect a coronal mass ejection hurled into space yesterday by an erupting magnetic filament to deliver a glancing blow to Earth’s magnetic field on Aug. 23rd. High-latitude sky watchers should be alert for auroras.

Listen to radar echoes from satellites and meteors, live on listener-supported Space Weather Radio.

via spaceweather


Common Believer by Sungrazer


Comet Lovejoy (2011 W3) rising over Western Australia (via


Comet Lovejoy evidently survives a close solar passage

A newfound comet defied long odds today (Dec. 15), surviving a suicidal dive through the sun’s hellishly hot atmosphere, according to NASA scientists.

Comet Lovejoy plunged through the sun’s corona at about 7 p.m. EST today (midnight GMT on Dec. 16), coming within 87,000 miles (140,000 kilometers) of our star’s surface. Temperatures in the corona can reach 2 million degrees Fahrenheit (1.1 million degrees Celsius), so most researchers expected the icy wanderer to be completely destroyed.

But Lovejoy proved to be made of tough stuff. A video taken by NASA’s Solar Dynamics Observatory (SDO) spacecraft showed the icy object emerging from behind the sun and zipping back off into space.


Sungrazer “Wild Goose”