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the comet is still showing an unexpected behavior that cometary specialists are fighting to explain

. The brightness has remained practically constant for more than 270 days or 9 months, a behavior without any precedent in cometary astronomy

presented and discussed what he identified as a peculiar photometric signature previously observed in disintegrating comets

. The following few weeks will reveal the real fate of weird Comet ISON.

No theoretical model exists capable of explaining all the observed phenomena with those defunct comets.

Several well known facts about the strange behavior of Comet ISON should be widely recognized.

It was expected that the comet would bright up after passing the "frost line

the comet has already passed that line and almost none has occurred.

ISON has surprised experts by maintaining almost unmodified its photometric behavior.

ISON faces other challenges

First, the comet will reach perihelion very near the Sun

calculated a temperature of 2,700 degrees Celsius, high enough to melt iron and lead

Second,

the comet will penetrate the solar Roche limit.

Any object penetrating this forbidden limit will experience solar tides that may tear apart the nucleus of the comet

The combination of temperature, radiation and tides may prove too much for the comet, which may not survive the encounter with the Sun

addition of gas and dust should cause the comet’s coma to increase in size.

this is the first look at cloud structures on a distant world.

observing this planet with Spitzer and Kepler for more than three years, we were able to produce a very low-resolution 'map' of this giant, gaseous planet

wouldn't expect to see oceans or continents on this type of world, but we detected a clear, reflective signature that we interpreted as clouds

Kepler-7b was one of the first

Kepler's visible-light observations of Kepler-7b's moon-like phases led to a rough map of the planet that showed a bright spot on its western hemisphere

data were not enough on their own to decipher whether the bright spot was coming from clouds or heat

Spitzer Space Telescope played a crucial role in answering this question

Spitzer can fix its gaze at a star system as a planet orbits around the star, gathering clues about the planet's atmosphere

Spitzer's ability to detect infrared light means it was able to measure Kepler-7b's temperature, estimating it to be between 1,500 and 1,800 degrees Fahrenheit (1,100 and 1,300 Kelvin).

relatively cool for a planet that orbits so close to its star -- within 0.06 astronomical units (one astronomical unit is the distance from Earth and the sun)

, too cool to be the source of light Kepler observed.

Instead, they determined, light from the planet's star is bouncing off cloud tops located on the west side of the planet.

Kepler-7b reflects much more light than most giant planets we've found, which we attribute to clouds in the upper atmosphere

the cloud patterns on this planet do not seem to change much over time -- it has a remarkably stable climate

With Spitzer and Kepler together, we have a multi-wavelength tool for getting a good look at planets that are trillions of miles away

exoplanet science

moving beyond just detecting exoplanets, and into the exciting science of understanding them

observations of Kepler-7b previously revealed that it is one of the puffiest planets known: if it could somehow be placed in a tub of water, it would float

found to whip around its star in just less than five days

a fully rendered 3D visualization tool, available for download at http://eyes.nasa.gov/exoplanets

program is updated daily with the latest findings from NASA's Kepler mission and ground-based observatories around the world as they search for planets

The technique, called proximity placement, uses the APXS as if it were a radar for assessing how close the instrument is to a soil or rock surface

The rover can interpret the data and autonomously move the turret closer if it is not yet close enough

This will enable placement of the instrument much closer to soil targets than would have been feasible without risk of touching the sensor head to loose soil

extra days of having team members check the data and command arm movement in response

demonstration test flight from the California coast carrying a Canadian satellite to an elliptical earth orbit

Both Cygnus and Falcon 9 were developed with seed money from NASA in a pair of public-private partnerships between NASA and Orbital Sciences and SpaceX

docking was delayed a week due to an easily fixed communications glitch

The Cygnus spacecraft

Hatches to Cygnus

opened on Monday, Sept. 30 after completing leak checks

second commercial partner’s demonstration mission reaches the ISS

Cygnus delivers about 1,300 pounds (589 kilograms) of cargo, including food, clothing, water, science experiments, spare parts and gear to the Expedition 37 crew

SpaceX Falcon 9 blasted off from Space Launch Complex 4 at Vandenberg Air Force Base in California

deployed Canada’s 1,060 pound (481 kg) Cascade, Smallsat, and Ionospheric Polar Explorer (CASSIOPE) weather satellite and several additional small satellites.

silver as an example

has the same number of protons

Silver has 47

not every atom of an element necessarily has the same number of neutrons

different versions of an element's atoms are called isotopes

Silver occurs as silver-109 and silver-107

Chemists calculate the atomic weight of an element that you see on the periodic table from the masses of its isotopes, giving more common isotopes more weight than less common isotopes

doesn't necessarily mean every sample of silver on Earth has an atomic weight of exactly

samples of elements vary from place to place

erences play an important role in many sciences

They help chemists trace the origin of different materials

and date archaeological findings

The latest atomic weights measurements differ too little from their predecessors to really change science

do it?"

If it's just small changes, why

should give the best numbers there are

some new idea will come up that needs more accurate data

Molybdenum, Losing 0.0122

Atomic weights are relative, so they don't have units

Thorium, Losing 0.000322

Yttrium and Niobium, Tied, Losing 0.00001

Selenium, Gaining 0.0088

Cadmium, Gaining 0.0026

Holmium, Thulium and Praseodymium, All Tied, Gaining 0.00001

The changes in weights mostly come from continuing improvements in atomic mass measurements

advances in the technology behind mass spectrometers

not all about measuring more accurately

thorium, the IUPAC decided to recognize an isotope, thorium-230, that it previously thought was too rare to include in atomic weight calculations

The last time international chemistry

really altered the periodic table was in 2009, when IUPAC decided to list the atomic weights of some elements as ranges, instead of single numbers

recently succeeded in collecting “really interesting” new high resolution survey scans of Solander Point

The new MRO data are crucial for targeting the rover’s driving in coming months.

Solander Point is an eroded ridge located along the western rim of huge Endeavour Crater where Opportunity is currently located

it will take some time to review and interpret the bountiful new spectral data and decide on a course of action

Expect that analysis to take a “couple of weeks”

The new CRISM survey from Mars orbit will vastly improve the spectral resolution – from 18 meters per pixel down to 5 meters per pixel

Another important point about ‘Solander Point’ is that it also offers northerly tilted slopes that will maximize the power generation during Opportunity’s upcoming 6th Martian winter

winter’s last six full months

The rover recently investigated an outcrop target called ‘Poverty Bush’.

deployed her 3 foot long (1 meter) robotic arm and collected photos with the Microscopic Imager (MI)

collected several days of spectral measurements with the Alpha Particle X-ray Spectrometer (APXS).

There are several geologic units that are overlapping

Opportunity is sitting on the contact

the east side of the contact are rocks maybe a billion years older than those on the west side of the contact

So far

has snapped over 184,500

images

total odometry stands at over 23.82 miles (38.34 kilometers) since touchdown on Jan. 24, 2004

key ingredient of plastic containers, car bumpers and other everyday items on Earth

strung together in long chains to form a plastic called polypropylene

Scientists used Cassini's composite infrared spectrometer (CIRS) instrument, which measures infrared light given off by Saturn and its moon, made the discovery

When Voyager 1 conducted the first close flyby of the moon in 1980, it recognized gasses in the moon's brown atmosphere as hydrocarbons.

measurement was very difficult to make because propylene's weak signature is crowded by related chemicals with much stronger signals

A moderately large telescope.

A comet's brightness

an "extended" object with the light inside the comet's head spread out over a larger area of space

(a dark sky) is absolutely necessary

telescope in the 8 to 12-inch range

magnification of at least 200 to 300 power

if you're trying to see the comet you’ll have much better success by looking off to one side of its position (averted vision) rather than staring right at it; in that way you’ll be able to better detect its faint and fuzzy image

if you're trying to see the comet you’ll have much better success by looking off to one side of its position (averted vision) rather than staring right at it; in that way you’ll be able to better detect its faint and fuzzy image

Tuesday, Oct. 15. 

the comet will appear 1.1 degrees above and to the left of Mars, while Mars itself is passing only 0.9 degrees above and to the left of the bluish 1st-magnitude star Regulus

Comet ISON continues to run roughly two magnitudes fainter than original projections

recent 'discovery' of a jet feature may be the key in understanding Comet ISON's behavior during the past 7 weeks

observers

have begun to notice a lengthening of Comet ISON's tail

might" be a sign that the sun's warmth has indeed begun to make the comet more active by way of sublimation