This article was originally published in conversation. (opens in new tab) This publication contributed articles to Space.com’s Voices of the Experts: Columns and Insights.
Alice Gorman (opens in new tab)Associate Professor of Archaeology and Space Studies, Flinders University
Forty-five years ago on August 20, 1977, an extraordinary spacecraft left the planet and embarked on a journey like no other. Voyager 2 will show us a close-up of an exoplanet for the first time. It’s like sending a fly to New York City and asking it to come back and report.
Voyager 1 was launched on September 5 after Voyager 2. Each Voyager is flanked by a gold record containing greetings, sounds, images and music from Earth.
The spacecraft are more or less twins, but their trajectories and scientific instruments differ. Voyager 1 then flew into interstellar space as both flew past Jupiter and Saturn. Voyager 2 has delayed its only visit to the ice giants Uranus and Neptune.
gallery: Celebrate Voyager’s 45th anniversary with these stunning solar system images
Upon reaching Uranus in 1986, Voyager 2 mapped pale blue-green clouds and a possible “dark spot” that was later confirmed by the Hubble Space Telescope.There is an unexpected magnetic field (opens in new tab), which drags a spiraling particle trail behind the planet as it rolls in its orbit.ten new moons (opens in new tab) Found, including grey craters (opens in new tab)and two new coal black rings.
Three years later, Voyager 2 reached Neptune and sent home images of turquoise and cobalt blue clouds spun by winds of up to 11,000 mph (18,000 km/h). A slate-colored “large black spot” indicates a storm the size of Earth.The largest moon, Triton, is dyed pink by methane ice and spews frozen nitrogen geysers (opens in new tab).
No spacecraft has returned since then.
message to the future
In addition to glimpses of these distant icy planets, the Voyager mission is even more fascinated by the famous golden record (opens in new tab). Commission led by visionary astronomer Carl Sagan worked for over a year (opens in new tab) Assemble materials to represent the earth. Music garnered the most attention as “the mixtape of the universe,” but that wasn’t the only bright spot.
One of the sounds of the earth is making stone tools (opens in new tab), or “knock”.This is the most durable technology ever designed by humans and their ancestors, used for about 3 million years (opens in new tab) From before to now. For most of human existence, the sound of rocks hitting rocks to separate sharp cutting pieces has been heard every day in every community.
On the record, you can hear the stones hitting your heartbeat.
In 116 images, a black scientist in a lab coat stoops over a microscope, layered earrings falling gracefully from her ears. Earrings are the subject of some debate: Will future alien audiences recognize the concept of “jewelry”?Hope this photo, along with the photomicrograph (opens in new tab) The cell division in Figure 17 will help the viewer understand that the science of microscopy is well known on our planet.
People record information in 55 languages (opens in new tab). Some are ancient languages like Akkadian (opens in new tab) And the Hittites, unheard of on Earth for thousands of years. The most frequently used words are “greetings”, “peace” and “friends”. Janet Sternberg’s Portuguese greeting simply says “peace and happiness for all”.
Finally, in 2018, Voyager 2, along with Voyager 1, surpassed the heliopause, where the solar wind is blown back by winds from interstellar space. Our galaxy is 100,000 light-years wide, and Voyager 2 is now less than 18 light-hours from Earth.
Both spacecraft send reed signals that travel between the planets to three antennas still listening: Tidbinbilla (opens in new tab)Goldstone and Madrid.
Voyagers will have to traverse the Oort Cloud, a huge, dark sphere of icy celestial bodies surrounding the solar system, for another 20,000 years before they can actually leave.
Slowly, Voyager 2’s systems are shutting down (opens in new tab) Maintain power for as long as possible. But at some point in the 2030s, there will be nothing left.
Even if Voyager 2 stops transmitting, it won’t completely freeze. The half-life of plutonium-238 in its NPS is 87.7 years, while the half-life of a coating of small pieces of uranium-238 is 87.7 years. (opens in new tab) It’s 4.5 billion years on the gold record. Both elements are slowly turning into lead.
The radioactive transmutation of elements is a kind of reverse alchemy on a cosmic time scale. The process of becoming will not end until there is nothing on Voyager 2 to revamp.
Continued bombardment of dust particles will gradually erode Voyager 2’s surface, possibly at higher speeds than Voyager 1, as it travels through different regions of interstellar space. However, its golden record should be at least partially clear in 5 billion years.
The Earth depicted on the golden record may not be recognizable even 100 years from now. The spacecraft and records will serve as a fragmented archaeological record for an unknowable future.
While the Golden Records are fascinating, the true cultural significance of Voyagers lies in their location. Spacecraft are boundary markers showing the physical extent of human contact with the universe.
When Voyager stops transmitting, it’s like losing your senses. Telescopes can only show us so much: nothing can replace being there.
Who will follow their path?
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