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The Voyager 1 space probe was launched from Cape Canaveral #OTD in 1977, a few weeks after Voyager 2.

Now it's the most distant human-made object – about 14.96 billion miles from Earth, racing away from us at 38,000 miles per hour with respect to the Sun.


Color photo of the Voyager 1 launch. The probe sits atop a rocket mounted on a larger rocket with twin solid fuel boosters – a Titan IIIE launch vehicle. The photo is taken just after ignition. The bottom of the rocket has lifted up about half the height of the gantry, and is engulfed in bright white flame and smoke.
Color plot of the Voyager 1 and Voyager 2 trajectories. While Voyager two visited all four outer planets, Voyager 1 took a quicker route to Jupiter and Saturn that sent it careening out of the solar system.
A color rendering of the Voyager 1 probe against a star field. Two prominent antenna gantries emerge from the main body of the probe, positioned underneath a large radio dish.

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Voyager 1’s outbound trajectory took it by Jupiter in 1979, then past Saturn the next year.

This time lapse of the Jupiter approach consists of 66 frames, take once per Jovian day. Look carefully for moons darting past, shadows flickering across the face of the planet.

Credit: NASA/JPL

Voyager 1 discovered three new moons (Prometheus, Pandora, and Atlas) shepherding Saturn's A- and F-rings.

It also uncovered a wealth of new information about basic properties of Saturn's moon Titan, from size to atmospheric composition.

Image: NASA/JPL-Caltech

A false-color image of Saturn taken by Voyager 1 in 1980. The planet's cloud bands appear as orange, yellow, white, and a pale blue-green. The ring system is a darker golden-brown, and the portion circling behind the planet is partly in shadow. The image is tilted at a roughly 30 degree angle, with the equatorial ring system stretching from the lower left to upper right corners of the photo.
A color photo of Titan sent back by Voyager 1. The hazy blue limn of an atmosphere is visible; the moon itself is a featureless yellow-orange.

The trajectory that gave Voyager 1 the best view of Titan (a mission priority) sent it out of the ecliptic and towards interstellar space.

Ten years later, in 1990, Carl Sagan suggested that the probe should point its camera back at the solar system for a family portrait.

The sixty frame mosaic captured by Voyager 1 on Valentine's Day of 1990 shows Jupiter, Earth, Venus, Saturn, Uranus, and Neptune.

Image: NASA/JPL-Caltech

A 60 frame mosaic of mostly black-and-white photos showing Voyager 1's view of the solar system as it sailed toward interstellar space. Color call outs show frames with Jupiter, Earth, Venus, Saturn, Uranus, and Neptune.

The frame containing Earth shows a dramatic optical artifact because we are near the Sun in the camera's field of view.

That's the Pale Blue Dot. Suspended in a sunbeam, captured from a distance of 40 AU by a probe out on the edge of darkness.

After that, mission scientists turned off Voyager 1's cameras to save power.


The "pale blue dot" photo. It shows three or four colored beams of light – optical artifacts – passing from the left side of the image to the right. The background is dark, empty space. In the topmost light beam is a single pale blue pixel. That's Earth. Sagan's quote is printed on the image. It reads ""We succeeded in taking that picture [from deep space], and, if you look at it, you see a dot. That's here. That's home. That's us. On it, everyone you ever heard of, every human being who ever lived, lived out their lives. The aggregate of all our joys and sufferings, thousands of confident religions, ideologies and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilizations, every king and peasant, every young couple in love, every hopeful child, every mother and father, every inventor and explorer, every teacher of morals, every corrupt politician, every superstar, every supreme leader, every saint and sinner in the history..."

By 1998, Voyager 1 was at 68 AU, further out than Pioneer 10.

Around 2004, at about 94 AU from the Sun, it crossed the termination shock and entered the heliosheath.

And in 2012, at 121 AU from the Sun, Voyager 1 crossed the heliopause and entered interstellar space.

But Voyager 1 hasn't left the solar system. At 161 AU, its current distance from the Sun is a fraction of Sedna's 936 AU aphelion (though it is currently further out than the minor planet).

And it's nowhere near the inner edge of the Oort cloud, thousands of AU from the sun.

This chart shows Voyager 1's location in 2013, with distance from the sun plotted on a log scale. It is at roughly the same place today, since the next step on the scale jumps from 100 to 1000 AU.

Image: NASA/JPL-Caltech

A color graphic produced by NASA which shows Voyager 1's distance from the Sun compared to other parts of the solar system and nearby stars. It is a log plot, so a wide range of distances are compressed onto a smaller scale. Each step on the horizontal axis corresponds to 10x the distance of the previous step. Voyager 1 is just outside 120 AU on this plot, in what is labeled "Interstellar Space," but it is still far from the inner edge of the Oort Cloud at around 1,000 AU.

So even though Voyager 1 has a long way to go, I wouldn't fault anyone for describing it as being at "the edge of the solar system."

It’s the fastest and most distant thing humans have ever made, it’s okay to sound a little dramatic.

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When we receive data from Voyager 1, we’re picking up a signal sent about 22 hours and 19 minutes ago.

Of all the objects humans have hurled into space, Voyager 1 is the closest to being one full light-day away from us.

The speed of light is 3 x 10⁸ m/s, and Voyager 1 is traveling at about 38,000 mph with respect to the Sun. A few conversions turns that into about 0.5 light-hours per year. So we're a little over three years away from Voyager 1 being one full light-day away from us.

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Six of the probe’s scientific instruments have been powered down. The other four will be shut off over the next few years. When it reaches a distance of one light-day we’ll still be able to communicate with it, but it won't have much to say.

Voyager 1 will remain in range of our Deep Space Network for some time after that. Eventually, though, it won't be able to muster enough power for a detectable signal, and will quietly sail off into darkness.
Image: NASA/JPL-Caltech

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I don't understand why we don't send out another few probes with much better technology that can last much much longer and provide SIGNIFICANTLY better data.
@CitizenFortress I think it's chiefly lack of political will. It would be awesome as a prestige project for a medium sized country.
Despite how much I really don't like Musk now, I think having SpaceX is a huge huge push in the right direction. Getting it out the hands of the government and into the hands of private entity is the best option forward, as business customers and businesses seem to push things much farther than governments do.
This is the best thread I read on Mastodon today, and I read the @vagina_museum one..
You need more hashtags for more reach though..
Because. Everyone. Needs. To. Read. This. Thread.
Thanks, I really enjoyed this thread and it sent me down a Oort Cloud versus Kuiper Belt rabbit hole.
And you can get updates via @NSFVoyager2 and

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I love how we’re even littering in SPACE though.
It's really quite headache-inducing to hold in my head the thoughts "A light-day away" and "Hasn't gotten near leaving the solar system's gravitational influence yet."
Multiply that by 365 and suddenly a light year doesn’t seem very large at all
The radio signal received is 10e-16 watts. One millionth of one billionth of a watt. As incredible as NASA's spacecraft designers are, people often overlook how incredible the Deep Space Network is.
it's the same as the series of discoveries of water on Mars. Every time it's actually something new and different from the previous instances, but it inevitably gets oversimplified to just "Breaking news: water on Mars!"
I have this above my headboard because Carl Sagan was a mythic epic genius
Sagan's words that describe this picture get to me every time.
Every time I read and see this I get goose bumps.
one of my all time favourite pictures, thank you 😊
Yes there we are, and we could share all we have with everybody so all would be happy and in unison with nature… instead mankind is the only animal that has created models and means to suppress their kind and reason some are mediocre because of skincolor or beliefs, and go to war committing planned murder and destruction on its own kind.
We do not deserve this pale blue dot…

Carl Sagan then wrote a book. „Pale Blue Dot: A Vision of the Human Future in Space“

Written in his typical positively visionary style, it comes recommended.

How do astronomers arrive at the length of a day for a gas giant?

There are various bands of fluid rotating in different directions in the time-lapse video

Given the relatively static nature of the Great Red Spot in Voyager 1’s photographs, I’m guessing that the rotational period of this well-known feature is (or was at the time) used as the rotational period of the planet as a whole, i.e. the length of a Jovian day

Or is the composition of Jupiter sufficiently well understood that it’s possible to calculate the moment of inertia of the planet about its rotational axis?

@transponderings They're all rotating the same way. The appearance of rotating in different directions is a result of capturing frames at fixed intervals while they move at slightly different speeds.

There's not too much variation in the speeds, though. Depending on whether you use polar or equatorial bands, the day varies by about 5 or 10 minutes. Another definition (used by IAU) is rotational period of the planet’s magnetosphere.

I love these pictures so much.
Thank you for the alt text.
It's humbling knowledge that this is still only 0.35% of the distance to the nearest star.
kms please (miles are not scientific measures)
I graduated from college in 1977, now almost retired. Voyager 1 has been traveling during my entire career. Likely that the folks tracking it are not those who began after the launch. During that time we’ve gone from a scientific calculator for $150 to smartphones that have more computing power than the room-size mainframes of the day probably used to calculate launch and trajectory parameters.
This entry was edited (3 weeks ago)