Over the last few weeks, I have covered a lot about the Pioneer and Voyager missions... it is not surprising that these are intriguing topics: these missions have changed planetary science and more. All four of these missions feature a pulsar map - which would ideally allow aliens who might find the spacecraft to work out where Earth is.

Well, not really. The idea behind the map is brilliant. Pulsars are exceptional timekeepers, as they pulsate with incredible regularity... but over time, they slow down. Also, nothing stays still in this universe. In the timeframe that the map works, the spacecrafts won't be far enough away that hypothetical ETs would be able to work out their origin.

So the question is, is there a way to find your position in space without the pulsars? For sure there is, but I was making it very complicated. I was thinking of the Celestial Reference Frame, a crucial component of standard GPS you have on your phone, which requires using quasars, the active state of a supermassive black hole at the center of distant galaxies. Well, a new study came out showing you that it can be done much more easily.

Scientists tested a new method for celestial navigation on New Horizons, the fifth spacecraft that will be able to leave the solar system like the Pioneers and the Voyagers. Using New Horizons cameras, the team observed the position of Proxima Centauri (the closest star to the Sun) and Wolf 359 (another nearby star). The spacecraft is so far away from Earth that we can compare the position of those stars from Earth and from its position, and use that to work out where New Horizons is. At the moment, the uncertainty of its position is quite big, in the tens of millions of kilometers, but this test was done without a specialized camera.

_{The parallax of Proxima Centauri (left) and Wolf 359 (right) as seen from Earth and by New Horizons on the same days in 2020. Image Credit: NASA/Johns Hopkins APL/SwRI}

We hardly do navigation by stars on Earth anymore, thanks to GPS, so it was funny that for finding our way around a new city we indirectly use supermassive black holes, and for a spacecraft to find its position as it goes towards interstellar space, you can simply look at nearby stars.

Obviously, it doesn't matter to know where you are if you do not care where you are going. Just ask Comet 3I/ATLAS, the third-ever known interstellar interloper to be discovered in the Solar System. And before any professor at Harvard makes a claim: no, it is not aliens!

Unrelated

Astronomers make mistakes too when it comes to space. It's me, I am the astronomer!

I set the telescope up two nights ago to catch the peculiar Lunar X, and despite getting some pretty pictures of the Moon, I realized too late that the Moon was going to set before the terminator reached the X, leaving me cold and tired and not eXceptionally pleased! But hey! Very pretty picture of the Moon!