Recent comments in /f/space

space-ModTeam t1_j9xxzxl wrote

Reply to Is it possible (at least theoretically) for an meteorite to ricochet from Earth instead of exploding? Are there any known cases (even if not on Earth)? by khukharev

Hello u/khukharev, your submission "Is it possible (at least theoretically) for an meteorite to ricochet from Earth instead of exploding? Are there any known cases (even if not on Earth)?" has been removed from r/space because:

  • Such questions should be asked in the "All space questions" thread stickied at the top of the sub.

Please read the rules in the sidebar and check r/space for duplicate submissions before posting. If you have any questions about this removal please message the r/space moderators. Thank you.

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Vindve t1_j9xxk90 wrote

Reply to Which space launch are you most excited for in 2023? by DealCommercial348

Ariane 6 first flight, in Q4 2023. European space desesperately needs it, as Ariane 5 production has been stopped. Ariane 6 may not be the perfect rocket (yes I know it's not reusable), but it's a better Ariane 5. 50% cheaper and looking awesome. Currently there is a market for it, it will buy time for Europe to figure out what's next.

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polaroppositebear t1_j9xx1n8 wrote

Reply to comment by khukharev in Is it possible (at least theoretically) for an meteorite to ricochet from Earth instead of exploding? Are there any known cases (even if not on Earth)? by khukharev

Something would have to be going incredibly fast and be massive enough not to have it's momentum reduced by the impact, at which point it would probably just sheer off a chunk of earth as it kept going.

Atmosphere will do nothing but slow an object down, increasing its odds of slamming into earth. Our planet is pretty soft so the chance of a ricochet like a bullet off a steel plate is very low.

Edit: also, once a meteorite is deep enough in earth's gravity well it won't be able to escape without some form of propulsion.

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marketrent OP t1_j9xwj1g wrote

Reply to Euclid space telescope launch scheduled for July — ESA mission to chart a 3D map of the universe, in search of dark matter and dark energy by marketrent

Excerpt from the linked content:^1

>Cannes (France) (AFP) – For now, Europe's Euclid spacecraft sits quietly in a sterilised room in the south of France, its golden trim gleaming under the fluorescent light.

>But in a few months the space telescope will blast off on history's first mission to search for two of the universe's greatest mysteries: dark matter and dark energy.

>How will Euclid, which is named after the ancient Greek founder of the field of geometry, observe something that cannot be seen? By searching for its absence.

>The light coming from billions of years in the past is slightly distorted by the mass of visible and dark matter along the way, a phenomenon known as weak gravitational lensing.

>"By subtracting the visible matter, we can calculate the presence of the dark matter which is in between," [Euclid project manager] Racca said.

>To do this, Euclid has two main instruments, a 1.2-metre (four-foot) diameter telescope and the Near Infrared Spectrometer and Photometer (NISP), which can split infrared wavelengths not visible to the eye.

> 

>Aiming to shed light on these dark secrets, the European Space Agency's mission will chart a 3D map of the universe encompassing two billion galaxies across more than a third of the sky.

>The third dimension of this map will be time -- because Euclid's gaze will stretch out to 10 billion light years away, it will offer new insight into how the 13.8-billion-year-old universe evolved.

>Partly what sets Euclid apart from other space telescopes is its field of view, which takes in an area equivalent to "two full moons", said David Elbaz, an astrophysicist at the French Atomic Energy Commission.

>This wide view will enable Euclid to locate massive structures like black holes that the Webb telescope cannot hope to find because its "field of view is too small", Euclid's project scientist Rene Laureijs told AFP.

>Only a few final tests remain before it heads to Cape Canaveral in the United States for a launch scheduled between July 1 and 30 on a SpaceX Falcon 9 rocket.

>Euclid was originally planned to get a ride into space on a Russian Soyuz rocket, but last year Moscow withdrew its launchers in response to European sanctions over its invasion of Ukraine, delaying the launch.

^1 AFP via France Médias Monde‘s RFI, 25 Feb. 2023, https://www.rfi.fr/en/science-environment/20230225-euclid-spacecraft-prepares-to-probe-universe-s-dark-mysteries

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Hispanoamericano2000 t1_j9xwfn6 wrote

Reply to How would radiation affect attempts to colonize the Galilean moons? by Old-Entertainment-91

From what I understand:

-The intensity of radiation on Io and the surrounding space is practically unbearable for anyone, even with existing protections that can be added to a spacesuit without making it unusable. Although Io's volcanoes could be an attractive energy source once the other moons are colonized.

-Europe is an improvement over Io, though not vastly better. I think it can be endured for only a few minutes on the surface before the dose becomes lethal. Any attempt at colonization would have no choice but to be carried out by burying the habitats under the ice, preferably in caves or canyons.

-Ganymede's radiation situation is orders of magnitude better than that of Io and substantially better than that of Europa, plus the moon also has its own magnetosphere (albeit shadowed by Jupiter's magnetic field) such that human settlement on the surface would be feasible. It would also be a feasible candidate for terraforming.

-Callisto is the most promising of the Galiean moons for human colonization, due to its distance from Jupiter's radiation belts. It was also the target selected by the HOPE (Revolutionary Concepts for Human Exploration of the Outer Planets) study. Building settlements on its surface should be quite feasible, and it was even considered that such settlements could be used as a fuel producer for further exploration of the outer solar system.

https://en.wikipedia.org/wiki/Colonization_of_the_Solar_System

https://www.universetoday.com/130637/colonize-jupiters-moons/

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Decronym t1_j9xvtvo wrote

Reply to Which space launch are you most excited for in 2023? by DealCommercial348

Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I've seen in this thread:

|Fewer Letters|More Letters| |-------|---------|---| |CST|(Boeing) Crew Space Transportation capsules| | |Central Standard Time (UTC-6)| |EVA|Extra-Vehicular Activity| |NG|New Glenn, two/three-stage orbital vehicle by Blue Origin| | |Natural Gas (as opposed to pure methane)| | |Northrop Grumman, aerospace manufacturer| |OFT|Orbital Flight Test| |SLS|Space Launch System heavy-lift|

|Jargon|Definition| |-------|---------|---| |Starliner|Boeing commercial crew capsule CST-100| |Starlink|SpaceX's world-wide satellite broadband constellation|

^(6 acronyms in this thread; )^(the most compressed thread commented on today)^( has 7 acronyms.)
^([Thread #8613 for this sub, first seen 25th Feb 2023, 10:20]) ^[FAQ] ^([Full list]) ^[Contact] ^([Source code])

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khukharev OP t1_j9xvtvm wrote

Reply to comment by Nosferatu-87 in Is it possible (at least theoretically) for an meteorite to ricochet from Earth instead of exploding? Are there any known cases (even if not on Earth)? by khukharev

Honestly, I am not sure what options could realistically be, so let’s treat it as “all of the above”. The one I had in mind was mostly about surface contact at an angle that allows for ricochet. But ricocheting off atmosphere could be an interesting option too.

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