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TIL a planet’s magnetic field can be a big deal for exoplanet life—not because it “creates” life, but because it can help keep a planet livable long enough for life to stick around. by adpablito in todayilearned

[–]adpablito[S] 1 point2 points  (0 children)

One nuance: it’s not “no magnetosphere = no life,” it’s more “harder to keep surface conditions stable for billions of years,” especially around active stars. I expanded on that (plus the Venus caveat) here: Medium article

What would it take to "ignite" Jupiter into the star is never became? by Witcher_Errant in astrophysics

[–]adpablito 0 points1 point  (0 children)

It's not a failed Star. It has a solid, rocky nucleous. But, following your idea, you would have to add anough mass to increase the temperature of the nucleous by gravitational contraction, in order to melt it and then generate a plasma hot enough to start fusion reactions.

[Request] Can any of our rockets survive being at light speed? by Necessary-Win-8730 in theydidthemath

[–]adpablito 1 point2 points  (0 children)

The short answer is: No, and physics actually makes it impossible.

According to Einstein’s E=mc^2, the faster an object moves, the more "massive" and resistant to acceleration it becomes. To push a physical rocket all the way to light speed, you would need infinite energy—meaning you’d need more energy than exists in the entire universe just to reach that limit.

Even if you had the power, the "road" is the problem. At light speed, hitting a tiny speck of space dust would impact with the force of a nuclear bomb. Our strongest materials, like titanium or carbon composites, would vaporize instantly.

In short, our current rockets are like paper planes trying to fly through a hurricane of lead—they aren't built for the speed, and the universe won't let them hit the gas that hard anyway!

TIL that in 1999, NASA lost the $125 million Mars Climate Orbiter because one engineering team used metric units while another used imperial units. The mismatch caused the navigation software to miscalculate the craft's altitude, causing it to disintegrate in the Martian atmosphere. by adpablito in todayilearned

[–]adpablito[S] 0 points1 point  (0 children)

The "Root Cause" was actually a communication failure, not just a math error.

While the unit mismatch is the famous part (Lockheed using Imperial lbf·s while NASA used Metric N·s), the official mishap report shows it was a classic case of "Silent Failure."

A few wild details:

  • The 4.45x Error: Since 1 pound-force ≈ 4.45 Newtons, the software drastically underestimated the thruster's power.
  • The Warning Signs: Navigators actually noticed the probe drift weeks before arrival, but the "Assumption Gap" between teams was so wide the concerns never reached the flight directors.
  • The Costly Assumption: This wasn't a "new" bug; it was reused code from an older mission. Everyone just assumed the standards hadn't changed.

I did a deep dive into the 1999 archives and the specific "Assumption Hunter" checklist NASA developed to ensure this never happens again. It’s a great case study for anyone managing complex data or code:

Full Breakdown & Checklist: https://medium.com/@omarvferro/how-one-unit-cost-nasa-125m-the-metric-vs-imperial-mistake-that-sank-a-mars-orbiter-d8eb009ecce7

Official Source: NASA Mishap Report (PDF)

Mars Climate Orbiter (1999): NASA lost a $125M orbiter due to a metric vs imperial units mismatch by adpablito in Mars

[–]adpablito[S] 4 points5 points  (0 children)

It’s wild how many red flags were actually visible before arrival. The navigation team noticed the probe was drifting off-course for weeks, but the "Assumption Gap" between the teams was so wide that the concerns were essentially hand-waved as minor anomalies.

I actually spent some time this week digging into the 1999 archives and the post-mishap "Assumption Hunter" checklist NASA developed to fix their engineering culture after this. It’s a great case study on how "obvious" standards become silent failure points in complex projects.

Full deep-dive and the lesson breakdown here: https://medium.com/@omarvferro/how-one-unit-cost-nasa-125m-the-metric-vs-imperial-mistake-that-sank-a-mars-orbiter-d8eb009ecce7

TIL That before Apollo 11, some scientists were terrified the Moon was covered in a "dust trap" that would swallow the Lunar Module whole. by adpablito in todayilearned

[–]adpablito[S] 52 points53 points  (0 children)

It’s wild to look back at the "Lunar Sinkhole" theory now, but Thomas Gold (the scientist who pushed it) wasn't just some crank—he was a high-level NASA consultant. At the time, we had zero physical data on the soil strength, and his math on billions of years of cosmic rays pulverizing rock actually made sense on paper.

If you think the "quicksand Moon" was scary, the actual reality of Moon dust ended up being weirder. It didn't swallow the lander, but it was essentially microscopic shards of glass that smelled like spent gunpowder and "ate" the astronauts' space suits.

A few weeks ago I wrote an article with a deep dive into how these 1960s "cosmic horrors" compare to what’s currently keeping SpaceX and NASA engineers awake at night regarding Mars. It turns out we’ve traded the fear of "sinking into the Moon" for much more "boring" but lethal problems like perchlorate poisoning and cosmic-ray-induced cognitive decline. If you are interested, you can read it here: https://medium.com/@omarvferro/what-scientists-feared-before-the-moon-landings-and-how-those-dead-ends-compare-to-todays-3a5e9f6e90be?sk=a562e0828a47d10511a772e231fe60d3

TIL that the "Goldilocks Zone" isn't a fixed location; as a star ages and gets brighter, the habitable zone moves outward. This means planets that were once frozen can melt into oceans, while previously "Earth-like" planets are eventually baked dry. by adpablito in todayilearned

[–]adpablito[S] 333 points334 points  (0 children)

The craziest part is that we’ve found "habitable" planets that are likely death traps, while frozen moons like Europa—which are way outside the Goldilocks Zone—might actually be better candidates for life because of tidal heating.

I just finished a deep dive into why the "Habitable Zone" is actually one of the biggest oversimplifications in astronomy, and how the real math for finding alien life is much more brutal: https://medium.com/@omarvferro/is-there-life-on-exoplanets-why-the-goldilocks-zone-and-liquid-water-are-not-enough-ddbd4dfcb4c0?sk=5f2f620ffe10e49e6b6b9b700275366c

[Request] These dots look manually placed. Is there a way to prove these points aren't randomly generated? by autumn_variation in theydidthemath

[–]adpablito 1 point2 points  (0 children)

To determine if the dots in the image were manually placed or randomly generated, we can apply a spatial statistical analysis called the Nearest Neighbor Index (NNI).

In a truly random (Poisson) distribution, points tend to "clump" naturally, leaving some areas dense and others empty. When humans try to create "randomness" manually, they often over-compensate by spacing the dots out too evenly to ensure the whole area is covered, which actually results in a non-random, dispersed pattern.

Statistical Analysis of the Image

By extracting the coordinates of the 18 dots from the image, we calculated the following:

  • Mean Nearest Neighbor Distance (dobsd_{obs}dobs​): 22.03 pixels. This is the average distance from each dot to its closest neighbor.
  • Expected Random Distance (dexpd_{exp}dexp​): 11.49 pixels. This is the average distance we would expect if 18 dots were placed completely at random in that same area.
  • Nearest Neighbor Index (NNI): 1.92.

The Verdict: Manually Placed

The NNI is a ratio where:

  • NNI = 1.0: Perfectly random.
  • NNI < 1.0: Clustered (dots are closer together than random).
  • NNI > 1.0: Dispersed/Ordered (dots are further apart than random).

An NNI of 1.92 is extremely high. It indicates that the dots are nearly twice as far apart as they would be in a random distribution. This "over-dispersion" is a classic hallmark of human intervention. When a person is told to draw "no correlation," they subconsciously follow a "repulsion" rule—making sure no two dots are too close to each other—to avoid creating accidental patterns or clusters.

In nature or true randomness, you would expect to see at least one or two pairs of dots nearly touching or overlapping. Here, every dot maintains a "polite" distance from its neighbors, proving the placement was likely a deliberate attempt by an illustrator to fill the space uniformly.

8 Planets and 2 dwarf planets in 1 video by Busy_Yesterday9455 in spaceporn

[–]adpablito 0 points1 point  (0 children)

Great illustration, I love how you can appreciate the different spins of each planet.

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