Comet ISON

On April 30, NASA's Hubble Space Telescope observed Comet ISON. (Courtesy of NASA, Baltimore Sun / July 16, 2013)

Comet ISON is alive and kicking, according to recent observations, and one study released last week found it could likely remain intact through its close pass by the sun next month.

That is good news for those hoping the comet will be visible from Earth at twilight late this year.

Recent observations show the comet's nucleus -- the ball of rock, mineral and ice from which its tail emanates -- is substantial, at somewhere between about 2/3 of a mile and 4 miles across, National Geographic reports. The Space Telescope Science Institute in Baltimore says it's more like slightly more than a mile across, citing its expert, Dr. Jian-Yang Li of the Planetary Science Institute.

That the comet has a large enough nucleus makes it less likely the sun's heat will split the comet into chunks, which might not shine as bright to be seen from Earth.

A study released Wednesday found that ISON's pass through the sun's corona, an intensely hot layer of plasma and charged particles, is not likely to doom the comet.

Researchers at the Lowell Observatory and Southwest Research Institute conducted numerical simulations to compare ISON to other sun-grazing comets and comets that were broken up by the sun, including comet Lovejoy in 2011, which put on a spectacular show regardless.

Amateur astronomers' images of the comet have begun to appear as ISON nears the sun, and more images from the Hubble Space Telescope are forthcoming. The telescope, managed from the telescope institute in Baltimore, was slated to take a new round of images on Wednesday.