Hubble's Latest View Shows Comet ISON Still Intact, Fairly Average

By Nancy Atkinson - October 17, 2013 at 7:39 PM UTC | Solar Astronomy
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We've been showing images of Comet ISON from amateur astronomers around the world, but now that NASA is back from the government shutdown, here's more proof that the comet is still intact and has not disintegrated ... despite some predictions to the contrary. This image was taken on October 9.

NASA explains:

In this NASA Hubble Space Telescope image taken on October 9, the comet's solid nucleus is unresolved because it is so small. If the nucleus broke apart then Hubble would have likely seen evidence for multiple fragments.

Moreover, the coma or head surrounding the comet's nucleus is symmetric and smooth. This would probably not be the case if clusters of smaller fragments were flying along. What's more, a polar jet of dust first seen in Hubble images taken in April is no longer visible and may have turned off.

This color composite image was assembled using two filters. The comet's coma appears cyan, a greenish-blue color due to gas, while the tail is reddish due to dust streaming off the nucleus. The tail forms as dust particles are pushed away from the nucleus by the pressure of sunlight. The comet was inside Mars' orbit and 177 million miles (284 million km) from Earth when photographed.

So, its not disintegrating, its not a three-piece body, its not a UFO... instead Comet ISON is turning out to be a rather average, ordinary comet. How has this comet sparked predictions that have gone from "bright as the full moon" to "disintegrating as we speak," asked Josh Sokol from the

Hubble ISON blog?

"Simply put, ISON peaked early. When it was first discovered, way out past Jupiter, ISON was really bright," Sokol wrote. "Extrapolated, those first data points made ISON look like it would shine even more as it got closer — and when it didn't, the coverage seesawed back toward calling ISON a total bust."

But ISON is still en route to the Sun. It will pass closest to the Sun on November 28, and if it remains intact after that close pass, it will make its closest approach to Earth on December 26, at a distance of 39.9 million miles (64 million km).

NASA is having a

live Hangout with Hubble comet scientists

to discuss the new image and latest research findings about ISON today (Oct. 17) at 4 p.m. EDT (20:00 UTC).

Update: here's the replay:

Also, check out the

Comet ISON Toolkit from NASA

Sources:

HubbleSite

,

Hubble ISON blog

Nancy Atkinson

Nancy Atkinson

Nancy Atkinson is a space journalist and author with a passion for telling the stories of people involved in space exploration and astronomy. She is currently retired from daily writing, but worked at Universe Today for 20 years as a writer and editor. She also contributed articles to The Planetary Society, Ad Astra (National Space Society), New Scientist and many other online outlets.

Her 2019 book, "Eight Years to the Moon: The History of the Apollo Missions,” shares the untold stories of engineers and scientists who worked behind the scenes to make the Apollo program so successful, despite the daunting odds against it. Her first book “Incredible Stories From Space: A Behind-the-Scenes Look at the Missions Changing Our View of the Cosmos” (2016) tells the stories of 37 scientists and engineers that work on several current NASA robotic missions to explore the solar system and beyond.

Nancy is also a NASA/JPL Solar System Ambassador, and through this program, she has the opportunity to share her passion of space and astronomy with children and adults through presentations and programs. Nancy's personal website is nancyatkinson.com