Tuesday, December 14, 2021

Parker Solar Probe Achieves a Major Mission Goal

A video posted today by NASA's Goddard Center says that the probe has achieved one of its major program goals and actually plunged into the corona.  The area that the probe entered is considered part of the sun so this is actually plunging into the sun. 

Saying the probe "touches the sun" is a bit on the poetic side, but the probe passed into the Corona and was touched by particles some of which are going back into denser parts of the sun, so a bit poetic and a bit accurate, too.  From the video description:

The new milestone marks one major step for Parker Solar Probe and one giant leap for solar science. Just as landing on the Moon allowed scientists to understand how it was formed, touching the very stuff the Sun is made of will help scientists uncover critical information about our closest star and its influence on the solar system.

I recalled the Parker Solar Probe both from having written about it back before launch and from seeing a news item once or twice.  It was starting a long term mission that would take it successively closer to the sun on each orbit and eventually reach the highest speed any man made object has ever achieved.  

The probe will be sent on its way atop a second stage mounted on a Delta IV heavy Lifter. It will go into a fairly eccentric elliptical orbit around the sun (see figure below). It will orbit the sun 24 times, and on seven of them will make flybys of Venus to increase its speed and tighten its orbit. The last orbit around the sun will take only 88 days traveling at up to 450,000 mph.

That speed of 450,000 mph is the fastest any man made object has flown by a large margin - the previous record holders were NASA's Helios I and Helios II probes (1974 and 1976, respectively) at 157,000 mph (253,000 km/h).  Still, Parker's 450,000 mph is .00067 of the speed of light.  At that speed, the nearest stars are over 6400 years away.  Add in the fact that we have no known way to generate that speed without multiple gravitational slingshots.

It's pretty cool stuff.  There's nothing I can say that's equal to what Goddard has put up on the project web page, so if you think solar physics and astronomy is interesting, head on over. 


  1. The next question is, at those speeds, why aren't we slinging a probe to do something similar, and having it broadcast atomic clock readings to see how slow time moves at those speeds, just to double-check Albert E.'s math ...?

    1. Your GPS does that verification every day. It's probably the only thing in daily life that depends on relativistic corrections to work properly.

      For GPS satellites time slows about 7,000 nanoseconds per day as compared to a stationary receiver just due to their speed.

      Clock slowing due to position in the gravity well: gravitational effects speed the satellite atomic clocks by about 45,000 nanoseconds. 45,000 nsec faster – 7,000 nsec slower due to time dilation means the clocks are 38,000 nsec per day faster for the GPS satellites. Radio waves travel about 1 foot per nanosecond, so without designing for the relativistic effects, the distance measurements to each satellite would be off by 38,000 feet (or about 7 miles) per day. In two days, 14 miles off, and so on.

      There's a pdf from the National Institutes of Standards and Technology,

      Part of blog post I did in 2015.

    2. And all the long-distance probes are also showing the time-dilation effect. There's a small but measurable difference between what should be the bounce-back signal time and what it actually is.

      And will be real interesting once both Voyagers leave the effects of our solar system and go into true 'outer space.' Will they survive the gravity waves? Will other things happen to them? Can't wait to find out.

    3. Noted, SiG, but the point would be to show an exact correlation based on the tremendous speeds achieved.

      Airplanes and space flight have already shown a differential, but GPS satellites are only moving at about 9,000 MPH, and as you said in the OP, we've never had anything going 450,000 MPH before now, and that, plus the incredible mass of the Sun, should be having a ridiculously huge time shift effect.

      I just want to see it.

      Based just on the velocity difference, that should be a daily increase of 2.25 million nanoseconds.

    4. To say that we have "never" had anything going 450,000mph is not correct. All kinds of particles (which have specific decay rates) have been accelerated near the speed of light. That has been done since the 1950's. And time dilation measurements (which is what you are referring to) have been done since then. Essentially, you accelerate something (like a muon or pion) near the speed of light (like 0.99c) and measure its decay time. One of the favorite experiments, if I remember correctly, is to use a proton beam (at something like 600MeV) to generate a muon beam, which is itself accelerated. The decay time for the muon is lengthened due to time dilation. I am also pretty sure that an experiment like that was done at FNAL in the late 90's when I was there.

      If you really want to see it, I am sure that you can find Phys Rev papers from the 50's, 60's, and 70's that describe both the experimental setup and results.

    5. It's all relative.

    6. Dear Anonymous,

      Thanks for checking the box marked "high-functioning Asperger's".

      When you can put an instrumentation package on an accelerated particle, instead of merely extrapolating nuclear decay rates from sub-atomic ephemera, you'll have a point to your pedantry, and science will have a far more substantial data-point, which was that for which I expressed a desire. The "anything" explicitly referenced was "any man-made object", something your punctilious yet pointless reply failed to note (probably because the possessive use of the pronoun "we" escaped your otherwise detailed attention).

      The day mankind creates a particle ex nihilo, and someone then accelerates it to 450,000 MPH your reply will actually be on-topic, and "we" will have something else of ours moving as fast as the Parker probe solar experiment referenced from the outset, rather than merely playing pinball with one of Nature's pre-extant tiny bits and bobs.

      I'm frankly surprised that you didn't simply refer us all to experiments in turning on a light, and moving that product at the speed of light(!), which would have been a reply observation roughly 1488 times more clever.

      So now, we have something at which to look forward.

    7. On the contrary, I thought you were actually expressing genuine interest in relativity. I was even going to go as far as to give you cites to some of the papers so that you could read them yourself. My mistake; I'm sorry.

      I am also not going to respond to your comment because it is apparent that you are in pain from your anger and vitriol. I will pray for you.

      With all sincerity, may God bless you and have a Merry Christmas.

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  3. Here's to old farts and their old blog posts. I did one about the Parker Solar Probe back in 2018.

    1. Leave a link when you say something like that. I'd like to go read.