Thread by @Deschscoveries

Since so many have asked, here’s my hot take on the spherules Loeb found and the manuscript he’s loudly rushed to the world. These are pretty typical cosmic spherules. Had he done the *obvious*--a control sample 100 km away from the meteor--he’d have found the same thing. 1/20

To claim these spherules were interstellar one must establish: 1) the 2014 meteor was interstellar; 2) it didn’t burn up completely; 3) debris was concentrated where they looked; 4) the spherules came from THAT meteor; AND 5) a solar system source is ruled out. 2/20

Not one of these was established, let alone the whole chain. VERY likely these spherules are plain vanilla micrometeorites from solar system asteroids that have reacted with sea water for tens of thousands of years. I elaborate on facts, and express my opinion, below. 3/20

The 2014 meteor was probably from our solar system. It would be interstellar if its speed was 45 km/s, and Space Force pinky swears it was; but for meteors you can check from the ground, those numbers are wrong 1/3 of the time (Devillepoix et al. 2019). 4/20

For fast speeds, error bars are ±20 km/s, and everything about this meteor seems more consistent with a speed of 25 km/s (Brown & Borovicka 2023), meaning it’s just another meteor from our asteroid belt. 5/20

A meteor at 45 km/s would have 99.9999% burned up (Desch et al. 2023, ACM2023). These are standard formulas in meteor physics. Tillinghast-Raby, Loeb & Siraj (arXiv) make some egregious physics errors when figuring 10% would survive. 6/20

The meteor location is not known to within tens of km. CNEOS reports locations to ±11 km. Siraj & Loeb (arXiv, not reviewed) try to use the Manus Island seismometer’s detection of the airburst to refine this. If the explosion arrived at 271.0±0.5 s it was 83.9±0.7 km away. 7/20

But look at their Figure 3. Can you say the first signal arrived at precisely 271 s and not 280 s? If not, then the distance is uncertain to within about 10 km. They don’t know where to look! Their Figure 4 even shows the meteor going the exact opposite direction! 8/20

Any material would be spread out over many tens of km2. This meteor disintegrated over 0.3 s, while moving tens of km to the east. Strewn fields are typically tens of km long.The Equatorial UnderCurrent would have spread sinking spherules tens of km. 9/20

The seafloor is littered with cosmic spherules from the last tens of thousands of years, *tens of millions* in their search area alone, outnumbering any from the 2014 meteor by thousandsfold. Loeb’s spherules don’t come with labels saying they are from the 2014 meteor. 10/20

Loeb asserts the 5 unusual spherules are from what he imagines is the meteor path, but they really didn’t sample away from the path, and it’s all small number statistics and circumstantial. Again, none of these spherules has to come from the 2014 meteor. 11/20

Loeb claims the chemistry of 5 spherules is unprecedented, even giving them the name “BeLaU”. Their Figure 10a shows they have huge excesses of Th, U, La, Nb, Ce, Ba, and depletions in Co, Zn, relative to presumed asteroidal material. 12/20

It took me 20 minutes to find a similar example in the literature. Figure 2 of Rudraswami et al. (2016; MaPS 51, 718) shows scoriaceous S-type spherules in the Indian Ocean with huge excesses of Th, U, La, Nb, Ce, Ba, and depletions in Co, Zn. 13/20

Why this chemistry? Because over tens of thousands of years, spherules react with sea water and sediments with these elements (Prasad et al. 2015; MaPS 50, 1013). Loeb’s spherules simply have sat on the seafloor for tens of thousands of years. 14/20.

As for Fe isotopes, measured values in the upper right of their Figure 17 suggest those spherules partially vaporized in our atmosphere and are from SOME meteor(s). But they all fall on the “terrestrial fractionation line” (TFL) like everything else in our solar system. 15/20

We expect spherules from another solar system would have very different Fe isotope ratios and array along a parallel line well above or below the TFL. This strongly suggests all these spherules are from solar system materials. (Hat tip @sethajacobson !) 15/20

Loeb’s strategy was to find spherules looking like nothing else on Earth. This strategy only works if you know what everything else on Earth looks like. And for that you need to learn from experts who’ve studied these things for decades. 16/20

But before taking the time to learn what’s normally on the seafloor, Loeb winks to the press that he hopes to find and press the buttons on an alien iphone, and ends the paper with “Another possibility is… extraterrestrial technological origin.” 17/20

That’s clickbait and not how science works. I, too, would be beyond excited to discover alien tech. But every claim has to run the gauntlet of peer review, and competent and responsible scientists eliminate mundane explanations until forced to speculate. 18/20

Instead, Loeb’s rule is if he doesn’t understand it, then “aliens” is a possibility, and we are small-minded and mediocre scientists for not dropping what we’re doing and checking that. Sorry, but I don’t have time to keep working on all the things Loeb doesn’t understand. 19/20

Before Loeb posts rough drafts on arXiv, jumps to speculative clickbait conclusions, issues press releases, writes books, and dupes himself and the public, he should read the literature and learn from (not dismiss) experts deeply passionate about asteroids and meteorites. 20/20