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Despite the recent whinging about whether or not the maps on the Pioneer and Voyager space probes might have been a big mistake that might lead to Earth being invaded by hostile aliens, it turns out that the pulsar maps included on these probes are actually worthless for determining the location of our Solar System. Pulsars were first discovered in 1967 by Jocelyn Bell-Burnell, and at the time they were believed to be unique and stable landmarks suitable for that purpose. However, subsequent discoveries have shown that they are not actually as stable and reliable as they were first believed. Ethan Siegel at Starts With A Bang has an article on this:
[...] While fear-mongers foolishly claim that hostile aliens could follow the Voyager maps back to Earth, the maps themselves are actually among the most useless information aboard Voyager. According to Frank Drake, who worked on the Voyager message with Carl Sagan:
"We needed to put something on the Voyager that said where it came from, and how long it was traveling... There was a magic about pulsars ... no other things in the sky had such labels on them. Each one had its own distinct pulsing frequency, so it could be identified by anybody, including other creatures after a long period of time and far, far away."
Although these identifiers were thought to be unique and stable, we now know that long-term changes will render this map useless. If you tried to identify Earth by the presence of Pangaea, you'd be sorely disappointed. By sending the messages we did with Voyager, we actually delivered a much more challenging problem to any aliens "lucky" enough to come upon it. The idea to send pulsar positions and frequencies was a brilliant one, but by the time anyone receives it, they'll only encounter one of the most difficult-to-decipher riddles we could have possibly imposed.
In summary, it turns out that pulsars are far from being as unique, rare, and stable as they were believed to be in the 1970s when they came up with the idea. There are an estimated one billion neutron stars in the Milky Way, and almost all of these will look like pulsars somewhere in space because their spin and magnetic axes aren't perfectly aligned and so they will beam radio waves in some direction. The pulsar periods are also not as unique as they were at the time believed, so any extraterrestrial finding the Voyager plaque will have a hard time figuring out which fourteen pulsars out of a billion are described. Second, the properties of a pulsar can change in unpredictable fashion. Pulsars have since been observed to appear and disappear as the orientations of their spins relative to Earth change due to various factors, such as their motion in space and events internal to the pulsar itself such as starquakes and pulsar speedup. If one really wanted to tell aliens were we were it would have been better to give them a description of the Solar System, with the astronomical properties and description of our sun and the planets. It is, after all, how we identify exoplanet systems today.
(Score: 5, Funny) by looorg on Friday August 18 2017, @11:41PM (6 children)
The alien overlords will not be impressed with our lack of pulsar knowledge. One wonders if this is what drives them into a killing frenzy.
(Score: 3, Funny) by takyon on Friday August 18 2017, @11:55PM
Wasn't this regularity [metawellness.com] of pulsars supposed to make space navigation a cinch for our space battleships?
We're literally lost in space!
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 3, Funny) by Anonymous Coward on Saturday August 19 2017, @12:35AM (3 children)
We're safe. The alien overlords are male and they are NOT going to stop and ask for directions.
(Score: 2) by looorg on Saturday August 19 2017, @12:49AM (2 children)
Not being male would/could explain why it's taking so long for them to get here, they are not even driving at the intergalactic speed-limit. Plus they are probably stopping at every store there is between there and here.
(Score: 5, Funny) by maxwell demon on Saturday August 19 2017, @04:51AM (1 child)
The danger is an alien couple. The female will ask for directions, and the male will drive at maximum speed and insist on her not visiting any shops. And on arrival, they will both be in very bad mood because of the inevitable arguments about visiting shops, his driving style, and so on. Destroying Earth will be a welcome opportunity for them to let off steam.
The Tao of math: The numbers you can count are not the real numbers.
(Score: 2) by melikamp on Saturday August 19 2017, @05:33AM
(Score: 0) by Anonymous Coward on Saturday August 19 2017, @08:08AM
Inter-Galactic Planetary Pizza Delivery
Driver: Captain, it's a fake address.
Captain: What? Again?? This is the last straw!
Driver: I told you it looked fishy. Who orders a pizza via probe?
Captain: Oh, shut up. You're cleaning the bathrooms when you get back!