Hubble charts road map for NASA probes' interstellar trip

Along the way, the Voyagers are measuring the interstellar medium, the mysterious environment between stars.

"Hubble gives context to what each Voyager is passing through," said study leader Seth Redfield of Wesleyan University in Middletown, Connecticut, US.

NASA launched the twin Voyager 1 and 2 spacecraft in 1977. Both explored the outer planets Jupiter and Saturn. Voyager 2 went on to visit Uranus and Neptune.

The pioneering Voyager spacecraft are currently exploring the outermost edge of the sun's domain.

A preliminary analysis of the Hubble observations reveals a rich, complex interstellar ecology, containing multiple clouds of hydrogen laced with other elements, the researchers said.

Even after the Voyagers run out of electrical power and are unable to send back new data, which may happen in about a decade, astronomers said they can use Hubble observations to characterise the environment through which these silent ambassadors will glide.

"This is a great opportunity to compare data from in situ measurements of the space environment by the Voyager spacecraft and telescopic measurements by Hubble," Redfield said.

Hubble data, combined with the Voyagers, have also provided new insights into how our sun travels through interstellar space, according to the study presented at the winter meeting of the American Astronomical Society in Grapevine, Texas.

"The Voyagers are sampling tiny regions as they plow through space at roughly 38,000 miles per hour. But we have no idea if these small areas are typical or rare. The Hubble observations give us a broader view because the telescope is looking along a longer and wider path," Redfield noted.

The astronomers hope that the Hubble observations will help them characterise the physical properties of the local interstellar medium.

"Ideally, synthesising these insights with in situ measurements from Voyager would provide an unprecedented overview of the local interstellar environment," Hubble team member Julia Zachary of Wesleyan University, noted.

--IANS

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