Well into its third decade of space exploration, NASA's Voyager 1 spacecraft cemented its place in the annals of human history when it officially reached interstellar space on Thursday. To mark the momentous achievement (Voyager 1 is now the furthest man-made object away from Earth), NASA scientists held a Reddit AMA on Friday.
During the online chat, NASA scientists and engineers answered Redditors' questions about Voyager 1's significance and its journey into heretofore unexplored regions of outer space.
See also: Voyager 1 Reaches Interstellar Space, a Milestone for Human Exploration
Voyager 1 announced the "Ask Me Anything" session via its Twitter account on Thursday:
I'm @NASAVoyager, now in #interstellar space. Ask me anything! Today Sept 12 3pm PT, 6pm ET, 2200 UTC http://t.co/48qhJKXWgd
— NASA Voyager (@NASAVoyager) September 12, 2013
The scientists involved confirmed their identities as the chat began:
The @NASAVoyager team at @NASA & @NASAJPL is ready to @reddit_AMA and answer your #interstellar Qs pic.twitter.com/aBJxFQ0wVy
— NASA JPL (@NASAJPL) September 12, 2013
The Q&A was filled with incredible facts about the Voyager mission, its scientists and interstellar space, which is over 11.6 billion miles away. When one Redditor asked if any of the team had been with the mission since its inception, Tim Krimings said, "I started in 1970 in planning the Grand Tour, and then was selected as principal investigator for Mariner-Jupiter-Saturn-77 (MJS-77) that became Voyager. And, I'm still at it!!" Krimings is the principal investigator for Voyager's low-energy charged particle. (The term Voyager, by itself, is used to refer to the mission as a whole, while adding 1 or 2 signifies one of the spacecraft.)
When asked about the continued relevance of such deep exploration, Bill Kurth, Voyager's plasma wave co-investigator, had a rather poetic answer: "James Van Allen once told me that the pursuit of knowledge was a sufficient answer for questions about applicability of space exploration. It's all about understanding who we are, where we come from and where we're going. We're all the stuff of stars, and now we're actually examining that 'stuff' ."
While the spacecraft is technically still in our solar system, it's cruising through a distant region of space beyond the heliosphere, which means it's now surrounded by material ejected not by our sun, but by the explosions of other nearby stars.
As Matt Hill, Voyager's low-energy charged particle science team member, defined it in the AMA, "Voyager 1 is currently surrounded by particles that came from other stars, not from our sun." Hill was 1 year old when the Voyager project officially began in 1972.
The artist concept from NASA, below, entitled "Voyager Goes Interstellar," illustrates the region in which Voyager 1 currently resides. The distance is measured in Astronomical Units; 1 AU is measured as the distance from the sun to the Earth, or 92,960,000 miles.
 
Space.com calls the Oort cloud (the furthest region from Earth in the image above) "the outer solar system's icy shell." It represents our solar system's boundary, and Voyager 1 won't cross that boundary for another 14,000 to 28,000 years, according to NASA.
Voyager 1 sends data back to Earth in the form of 0s and 1s, and it will continue to do so until its nuclear battery runs out, which will likely happen around 2025. Until that time, we'll keep communicating with it, albeit slowly. "A signal from Voyager 1, traveling at the speed of light, takes 17 hours one way to reach Earth," Courtney O'Connor, who is part of Jet Propulsion Laboratory's social-media team, revealed in the AMA.
"No one has been to interstellar space before, and it's like traveling with guidebooks that are incomplete," Ed Stone, Voyager's project scientist at CalTech, said in a NASA press release. "Still, uncertainty is part of exploration . We wouldn't go exploring if we knew exactly what we'd find."
To read the full AMA (and we recommend you do), head over to Reddit.
Image: NASA/JPL-Caltech
BONUS: 55 Astonishing Images of Earth From Space
Taken April 20, 2013 by the Operational Land Imager (OLI) on Landsat 8. These formations are part of the Great Barrier Reefs in Australia. This area lies on the east coast of Queensland’s Cape York Peninsula.
Taken Feb. 3, 2003 by the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Aqua satellite. Fires are marked in red.
Taken Dec. 5, 2003 by the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Aqua satellite.
Taken May 22, 2013 by the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Aqua satellite, captured behind Isla Socorro, a volcanic island in the Pacific Ocean located off the western coast of Mexico.
Taken May 31, 2013 by a member of the International Space Station crew using a Nikon digital camera. Located in the Pacific Ocean, Gaua island is the top of a stratovolcano part of the Vanuatu Archipelago.
Taken April 20, 2013 by a member of the International Space Station crew using a Nikon digital camera.
Taken May 24, 2013 by a member of the International Space Station crew using a Nikon digital camera.
Taken May 18, 2013 by a member of the International Space Station crew using a Nikon digital camera. Pavlof Volcano, located on the Alaskan peninsula, began erupting on May 13, 2013.
Taken June 23, 2013 by a member of the International Space Station crew using a Nikon digital camera. The Strait of Tiran links the Gulf of Aqaba and the Red Sea, south of Saudi Arabia.
Taken Feb. 5, 2013 by the Advanced Land Imager (ALI) on the Earth Observing-1 (EO-1) satellite.
Taken Feb. 10, 2011 by a member of the International Space Station crew using a Nikon digital camera. This agricultural region is located southwest of the city of Perdizes in the Minas Gerais state of Brazil.
Taken March 23, 2013 from the WorldView-2 satellite. The Wilkins Ice Shelf, located on the Antarctic Peninsula, has experienced a series of breakup events since 1998.
Taken Dec. 14, 2004 by the Thematic Mapper (TM) on Landsat 5. The Mergui Archipelago in southern Myanmar lies along the border with Thailand.
Taken May 5, 2013 by the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra satellite.
Taken Oct. 30, 2012 by the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi NPP satellite. The image is rotated, looking south from Canada -- north is at the bottom of the image.
Taken Nov. 12, 2012 by the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Aqua satellite. The image shows the Guadalquivir River emptying sediment deposits into the Gulf of Cádiz.
Taken Sept. 18, 2001 by the Enhanced Thematic Mapper Plus (ETM+) on Landsat 7.
Taken on July 31, 2009 by the Advanced Land Imager (ALI) on the Earth Observing-1 (EO-1) satellite. The Cocos (Keeling) Islands, comprised of coral atolls and islands, lie in the eastern Indian Ocean northwest of Perth, Australia.
Taken Sept. 10, 2009 by the Thematic Mapper (TM) on Landsat 5.
Taken on Aug. 9, 2012 by a member of the International Space Station crew using a Nikon digital camera.
Taken Sept. 2, 2000 by the Enhanced Thematic Mapper Plus (ETM+) on Landsat 7. The image pictures an area east of Alaska in Canada and includes Liverpool Bay, the Eskimo Lakes and the Tuktoyaktuk Peninsula.
Taken Sept. 2, 2011 by the Thematic Mapper (TM) on Landsat 5. The image was taken nearly a week after Hurricane Irene dumped large amounts of rain onto New England.
Taken on Sept. 28, 2011 by the Advanced Land Imager (ALI) on the Earth Observing-1 (EO-1) satellite. The Nabro Volcano is located in the Danakil Desert on the border between Eritrea and Ethiopia.
Taken on Sept. 17, 2011 by a member of the International Space Station crew using a Nikon digital camera.
Taken July 23, 2011 by the Advanced Land Imager (ALI) on the Earth Observing-1 (EO-1) satellite. The Medvezhiy Glacier in Tajikistan started to slide abruptly in summer 2011, having moved 800 to 1,000 meters from June to July 2011, faster than its normal 200 to 400 meters in a year.
Taken Sept. 22, 2002 by the Enhanced Thematic Mapper Plus (ETM+) on Landsat 7. The Yukon River flows from British Columbia, Canada, through Yukon Territory before emptying out into the Yukon Delta in southwestern Alaska.
Taken March 10, 2011 by a member of the International Space Station crew using a Nikon digital camera.
Taken Jan. 23, 2011 by a member of the International Space Station crew using a Nikon digital camera. Durrat Al Bahrain is a series of 14 artificial islands created for residents and tourists located at the southern end of Bahrain Island in the Persian Gulf.
Taken June 24, 2006 by the Thematic Mapper (TM) on Landsat 5. These islands lie along the northeastern coast of Brazil.
Taken Nov. 7, 2007 by a member of the International Space Station crew using a Kodak digital camera.
Taken October 5, 2010 by a member of the International Space Station crew using a Nikon digital camera.
Taken Sept. 30, 2010 by a member of the International Space Station crew using a Nikon digital camera. The Syr Darya River flows from the Tien Shan Mountains in Central Asia to the Aral Sea. This floodplain is in Kazakhstan.
Taken June 23, 2011 by the Advanced Land Imager (ALI) on the Earth Observing-1 (EO-1) satellite. Floods receded in the Wabash-Ohio Confluence after spring flooding in the Mississippi River basin extended to the region.
Taken June 24, 2007 by the Advanced Land Imager (ALI) on the Earth Observing-1 (EO-1) satellite.
Taken June 21, 2013 by the Operational Land Imager (OLI) on Landsat 8. The image shows the beginning of Greenland's summer melt.
Taken July 1, 2009 by a member of the International Space Station crew using a Nikon digital camera. Previously known as Caroline Island before 2000, Millennium Island is an uninhabited island part of the Republic of Kiribati in the South Pacific Ocean.
Taken Dec. 22, 2002 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on the Terra satellite.
This composite includes images taken in April and October of 2012 by the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi NPP satellite.
Taken Aug 13, 2010 by a member of the International Space Station crew using a Nikon digital camera. The Mataiva Atoll is part of the Tuamotu Archipelago in French Polynesia, the largest chain of atolls in the world, in the South Pacific Ocean.
Taken Oct. 4, 2010 by the Advanced Land Imager (ALI) on the Earth Observing-1 (EO-1) satellite. The Imja Glacier flows through eastern Nepal and eventually empties into the Ganges River.
Taken Sept. 28, 2010 by a member of the International Space Station crew using a Nikon digital camera.
Taken June 30, 2009 by the Advanced Land Imager (ALI) on the Earth Observing-1 (EO-1) satellite. Tikehau Atoll is a part of French Polynesia in the South Pacific Ocean.
Taken May 19, 1999 by the Enhanced Thematic Mapper Plus (ETM+) on Landsat 7. This is a false-color composite image.
Taken Aug. 4, 2002 by Landsat 7. This is Foxe Basin near Baffin Island in the Canadian Arctic.
Taken Sept. 25, 2000 by the Enhanced Thematic Mapper Plus (ETM+) on Landsat 7. This is a false-color composite image.
Taken on June 16, 2010 by the Advanced Land Imager (ALI) on the Earth Observing-1 (EO-1) satellite.
Taken Aug. 22, 1999 by the Enhanced Thematic Mapper Plus (ETM+) on Landsat 7.
Taken April 26, 2000 by the Enhanced Thematic Mapper Plus (ETM+) on Landsat 7.
Taken May 10, 2001 by the Enhanced Thematic Mapper Plus (ETM+) on Landsat 7. New Caledonia is a French-governed archipelago east of Australia. Its lagoons were added as a World Heritage site in 2008.
Taken Jan. 17, 2001 by the Enhanced Thematic Mapper Plus (ETM+) on Landsat 7.
Taken Jan. 10, 2013 by a member of the International Space Station crew using a Nikon digital camera.
Taken on June 12, 2009 by a member of the International Space Station crew using a Nikon digital camera. Sarychev Volcano is located on Matua Island, part of the Kuril Islands east of Russia and Japan.
Taken on Feb. 4, 2011 by the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra satellite. The Shinmoe-dake Volcano on the island of Kyushu in Japan began erupting on Jan. 26, 2011.
Taken July 13, 2005 by Landsat 7. These phytoplankton swirls surround the Swedish island of Gotland in the Baltic Sea.
Taken Sept. 11, 2001 by a member of the International Space Station.