Brainy Quote of the Day

Monday, March 13, 2017

ET, FRBs and Light Sails...

Image Source: Science Alert
Topics: Astrophysics, Photonics, SETI, Solar Sail, Space Exploration

It's not the first time I've discussed Fast Radio Burst (FRBs): I had posts in 2013, 2015 and just last year in 2016. I first read this in Science Alert, then followed the links to arXiv. Although I've posted from physics arXiv before, some things I should give as a caveat emptor:

- The arXiv is a pre-print journal, i.e. it precedes publication in peer-reviewed, scientific journals.
- As such, it's a good way to "get an idea out there." The first stringent peer reviews should be from your own research team. You can also in subsequent submission to scholarly publications correct previous conclusions, especially after peer challenge.
- You can submit your paper here, if you're a registered author.

What took me aback was a Harvard astrophysicist* submitting it, and it's apparently not as the colloquial phrase goes, his first rodeo (see #P4TC related link below). I was a little thrilled and a little worried if the hypothesis falls flat.

However, it does work on physics that we know, or at least think we know: we haven't built a functional solar sail YET, but it's a little more practical on our humble 0.7 Kardashev Scale than warp drive (to the chagrin of my inner Trekkie), but within the realm of reasonable relativistic speeds, a fraction of light speed, but doable.

If we're receiving these fast radio bursts, the question are: is this just stellar phenomena, a lucky observation break, or are we in a flight path? And if the latter, for what purpose?

* Loeb admits that this work is speculative. When asked whether he really believes that any fast radio bursts are due to aliens, he replied, "Science isn't a matter of belief, it's a matter of evidence. Deciding what’s likely ahead of time limits the possibilities. It's worth putting ideas out there and letting the data be the judge.”

We examine the possibility that Fast Radio Bursts (FRBs) originate from the activity of extragalactic civilizations. Our analysis shows that beams used for powering large light sails could yield parameters that are consistent with FRBs. The characteristic diameter of the beam emitter is estimated through a combination of energetic and engineering constraints, and both approaches intriguingly yield a similar result which is on the scale of a large rocky planet. Moreover, the optimal frequency for powering the light sail is shown to be similar to the detected FRB frequencies. These `coincidences' lend some credence to the possibility that FRBs might be artificial in origin. Other relevant quantities, such as the characteristic mass of the light sail, and the angular velocity of the beam, are also derived. By using the FRB occurrence rate, we infer upper bounds on the rate of FRBs from extragalactic civilizations in a typical galaxy. The possibility of detecting fainter signals is briefly discussed, and the wait time for an exceptionally bright FRB event in the Milky Way is estimated.

Physics arXiv: Fast Radio Bursts from Extragalactic Light Sails
Manasvi Lingam, Abraham Loeb


Light Sails Leakage, September 9, 2015

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