Frozen Giant Wakes: Unexpected Jet Activity Spotted in Deep Space Comet todayheadline

Scientists using the world’s most powerful radio telescope array have caught a massive comet behaving in unexpected ways while still freezing cold and incredibly distant from the Sun.

The observations reveal carbon monoxide gas erupting in evolving jet patterns from comet C/2014 UN271—a 140-kilometer-wide ice ball that represents the largest known comet from the mysterious Oort Cloud.

The findings, published in The Astrophysical Journal Letters, mark the first detection of molecular activity in this record-breaking comet and provide new insights into how these ancient objects work when operating far beyond the warmth that typically drives cometary behavior.

Watching Jets Evolve in Real Time

Using Chile’s Atacama Large Millimeter/submillimeter Array (ALMA), researchers observed C/2014 UN271 in March 2024 while it sat 16.6 times farther from the Sun than Earth—roughly the distance to Uranus. At such extreme distances, most comets remain completely dormant.

But this cosmic giant proved surprisingly active. The telescope detected carbon monoxide gas streaming away from the nucleus in asymmetric jets that shifted dramatically between observation sessions just nine days apart.

“These measurements give us a look at how this enormous, icy world works,” said lead author Nathan Roth of American University and NASA Goddard Space Flight Center. “We’re seeing explosive outgassing patterns that raise new questions about how this comet will evolve as it continues its journey toward the inner solar system.”

Temperature Clues From Gas Speed

The research team made a particularly intriguing discovery that wasn’t highlighted in initial announcements: they could calculate the comet’s surface temperature by measuring how fast carbon monoxide gas was moving away from the nucleus.

The gas expansion speeds revealed surface temperatures around 60 Kelvin (minus 213 degrees Celsius)—significantly colder than the 95 Kelvin predicted by standard thermal models. This unexpected finding suggests the comet’s surface properties differ from typical assumptions about how these objects absorb and emit heat.

The consistent gas speeds across different observation dates also indicate the jets originate from specific active regions on the nucleus rather than random outbursts.

Ancient Chemistry Preserved

C/2014 UN271 represents a scientific treasure because it’s making its first journey into the inner solar system after spending millions of years in the deep freeze of the Oort Cloud. This remote shell of icy objects preserves materials from our solar system’s earliest days.

The carbon monoxide production rates measured by ALMA—reaching 4.7 × 10²⁷ molecules per second—rival those seen in the famous Hale-Bopp comet when it was at similar distances. However, given UN271’s much larger size, this suggests its surface composition differs significantly from other well-studied comets.

Multiple Activity Patterns

The observations revealed a complex two-component outgassing system:

• A fast-moving sunward jet producing gas at 0.386 kilometers per second
• A slower, more diffuse component at 0.212 kilometers per second
• Evolving spatial patterns that changed between observation epochs

Complementary optical observations from Las Cumbres Observatory telescopes showed the comet experienced a significant outburst in late February 2024, brightening by nearly half a magnitude before gradually returning to normal levels during the ALMA observation period.

What Happens Next?

As C/2014 UN271 continues approaching the Sun, reaching its closest point in 2031 at Saturn’s distance, scientists expect additional frozen gases to activate. Based on temperature thresholds, methane outgassing may have already begun, with ethane, hydrogen sulfide, and other volatiles potentially activating as the comet warms further.

The research demonstrates how modern telescope technology can probe the behavior of objects at previously impossible distances. Why does this matter beyond scientific curiosity? Understanding these pristine time capsules helps reveal the chemical conditions present when planets formed—including the sources of water and organic compounds that made Earth habitable.

ALMA’s exceptional sensitivity allowed scientists to detect the faint radio signals from carbon monoxide molecules even at such extreme distances, opening new possibilities for studying the outer solar system’s most ancient residents.

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