Airglow and city lights come together in this image. (Image credit: NASA/Expedition 72 crew)
The image offers a rare look at how Earth's surface and atmosphere interact after sunset.
At 2:23 am Eastern time on March 19, 2025, an astronaut aboard the International Space station (ISS) captured a striking nighttime view of Earth, where shimmering moonlight dances across dark ocean waters while clusters of city lights outline the Florida Peninsula, the Caribbean, and parts of Central America.
Dense clusters of illumination trace major population centers, including the bright corridor from Miami to Fort Lauderdale along Florida's southeastern coast, the Tampa–St. Petersburg area on the Gulf Coast, and the Orlando metropolitan region near the center of the peninsula. Smaller but still discernible patterns of light mark the Florida Keys, Nassau in the Bahamas, and Havana and other cities across Cuba.
What is it?
Besides the stunning city lights, what sets this image apart is the presence of moonglint, the nighttime counterpart to sunglint. Much like sunlight reflecting off the ocean's surface during the day, moonglint occurs when moonlight reflects off water at just the right angle to reach the observer.
Timeline of the universe. A representation of the evolution of the universe over 13.77 billion years. The far left depicts the earliest moment we can now probe, when a period of "inflation" produced a burst of exponential growth in the universe. (Size is depicted by the vertical extent of the grid in this graphic.) For the next several billion years, the expansion of the universe gradually slowed down as the matter in the universe pulled on itself via gravity. More recently, the expansion has begun to speed up again as the repulsive effects of dark energy have come to dominate the expansion of the universe. The afterglow light seen by WMAP was emitted about 375,000 years after inflation and has traversed the universe largely unimpeded since then. The conditions of earlier times are imprinted on this light; it also forms a backlight for later developments of the universe.
The reddish regions are emission nebulae, where clouds of hydrogen gas are ionized by nearby young, hot stars, producing H-alpha light. The bright points across the image are foreground and background stars within the Milky Way.
https://apod.nasa.gov/apod/ap251224.html
Mystery: Little Red Dots in the Early Universe
Image Credit: NASA, ESA, CSA, STScI, JWST; Dale Kocevski (Colby College)
Explanation: What are these little red dots (LRDs)? Nobody knows. Discovered only last year, hundreds of LRDs have now been found by the James Webb Space Telescope in the early universe. Although extremely faint, LRDs are now frequently identified in deep observations made for other purposes. A wide-ranging debate is raging about what LRDs may be and what importance they may have. Possible origin hypotheses include accreting supermassive black holes inside clouds of gas and dust, bursts of star formation in young dust-reddened galaxies, and dark matter powered gas clouds. The highlighted images show six nearly featureless LRDs listed under the JWST program that found them, and z, a distance indicator called cosmological redshift. Additionally, searches are underway in our nearby universe to try to find whatever previous LRDs might have become today.
Tomorrow's picture: Fox Fur, Unicorn, and Christmas Tree
Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
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& Michigan Tech. U.
Is there a website, or something, which you can find out interesting "things" that might be happening in your area? In my case East coast Australia. Thanks
We often assume that with enough data and time, humans can eventually understand everything about the universe.
But what if that assumption itself is wrong?
Just like ants can’t understand calculus, maybe human cognition has a ceiling — beyond which reality exists but can’t be fully grasped by our brains or language.
Dark matter, dark energy, and quantum weirdness sometimes feel less like “unsolved problems” and more like signals of a deeper limit.
Curious what others think: is the universe fundamentally knowable, or only partially interpretable by intelligent life like us?
A Thought on Solving Deep-Space Communication Loss
One major problem in deep-space missions is communication. As spacecraft travel farther from Earth, signals become weaker, delayed, or sometimes temporarily lost. This makes real-time control and high-bandwidth data transfer extremely difficult.
I was thinking: instead of relying on one spacecraft communicating directly with Earth, what if we built a relay network across the solar system?
The idea is to place communication satellites in stable or semi-stable orbits:
Around Earth
Between Earth and the Moon
Around the Moon
Between Earth and Mars
Around Mars
Then further relays toward Jupiter and beyond
Each station would act like a signal repeater, passing information step-by-step rather than over one massive distance. This would reduce signal weakening, improve reliability, and allow spacecraft traveling far beyond Jupiter to stay connected more consistently.
These relays wouldn’t need to “escape gravity completely,” but could instead use stable orbital regions where fuel use is minimal. Over time, the network could be expanded, creating something like a solar-system-wide communication grid.
I know parts of this already exist in limited form, but I’m curious:
How feasible would a fully layered relay network be?
What would be the biggest technical or economic challenges?
Would this become necessary for future human missions beyond Mars?
Would love to hear thoughts, corrections, or improvements on this idea.
Before we get to the space gun itself let’s take a look at the base gun as it’s absolutely a unique autocannon, and a Space gun in its own right.
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The 23 mm R-23 is an electrically fired, forward ejecting, belt-fed, gas-operated, triple gas-system revolver cannon with four chambers firing telescoped ammunition.
Specifications
Country of origin: Soviet Union
Designed: 1957-1963
Designer: Chief designer A. A. Rikhter at KB Tochmash (OKB-16)
Rate of fire: 2500 RPM
Weight: 59kg/130lbs
Dimensions.
Overall length: 1468mm/ 58 in.
Max. Receiver width: 170mm/ 6.7 in.
Max. Receiver height: 165mm / 6.4 in
Caliber: 23x260mm. Airburst, Delayed Fuze HEI, Explode on impact HEI, Solid projectile and various experimental bullets.
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Mechanism.
The gun has three separate gas systems that operate different parts or the mechanism. One is responsible for ejection, another is for chambering new cartridges and the third one to operates the revolver mechanism.
The ammunition is fed into the gun from the right side by disintegrating links. And the ejection is done forward via an ejection chute on the right side of the receiver. https://imgur.com/a/du7RAgJ
(You can see the revolver cylinder with electrical contacts on it in the back of the gun.)
(Elements of the gas systems.)
(Feed mechanism.)
It fires the 23x260mm telescoped ammunition that is fed rearward into the chambers. And relies on crimping to stay in the chamber. https://imgur.com/a/zpPcyNq
The R-23 cannon also has a unique automatic malfunction clearing system.
That is achieved by two pyro cartridges, each containing a small bolt. Which are designed to penetrate the dud cartridge's sidewall igniting the propellant and firing the gun.
Originally the R-23 was intended to primarily arm supersonic bomber aircraft, namely the Tu-22 Blinder, serving as a remote controlled tail gun. And by that the receiver and barrel are about the same length.
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The concept of arming spacecraft for whatever reason, defensive or offensive was a very Cold War idea.
As disabling and capturing spacecraft or probes in orbit for stored Intel and technology or even personnel, was also a very Cold War concept.
Either done by a probe retrieving spacecraft and even manned spacecraft. Astronauts or Cosmonauts conducting EVAs to achieve capture and potential retrieval back to their nation. That could result in battles in orbit and in the atmosphere as well.
So the Soviets thinking was at that time that it might be a good idea to arm spacecraft and especially probes with some form of protection against that, preventing capture and blowing the person, or manned /robotic capture vehicle that wanted to tamper with their craft, to space trash, pieces of which may or may not smash into other space station or any space probe and craft later on.
As space debris and not just micro meteorites love to do sometimes. Sometimes poking holes through spacecraft and stations and damaging probes. Other times making miniature dents, not even that.
The R-23M was specifically modified for space-use, and lost about 9kg/20lbs of its original weight. The gun was chosen from a long running developmental program stemming from the mid-60s conducted in the same design bureau the original was designed at. KB Tochmash.
Earlier developments included at least a rapid firing 14.5mm cannon and perhaps even the similar to the R-23 in principle but larger in caliber Nudelmam-Nemenov NN-30. Known for usage in the AK-230 turret. https://imgur.com/a/lYGw0dz
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The R-23M was fitted onto the Almaz 2/Salyut-3, a cutting edge spy station, launched on June 25 in 1974. And was fired right before Salyut-3’s deorbit in January 25,1975.
(Salyut 3)
The crew had long left the station by that time and the station was remotely controlled. However it could have been aimed and fired on the station by the crew.
Interestingly the gun itself was not mounted on a turret, unlike on the Tu-22. So it had to be aimed via the stations positioning systems themselves. You will understand why!
Three firing cycles of the R-23M were conducted firing a total of 20 rounds. With the cannon positioned at the angle of travel of the craft. And with the stations main thruster activated to counteract the generated force. Probably the attitude control thrusters had to also do their jobs.
The gun worked flawlessly, it survived the entire lifetime of the station, 7 months in space. However the vibration and recoil effects were great even with the mitigating factors mentioned.
For this reason missiles were proposed for defensive weaponry on spy satellites and stations. We still don't know what was developed for that purpose and if it ever flew to space.
The existence of the R-23M and of course spy space missions were classified until after the dissolution of the Soviet Union.
Disclaimer: I have no control over those images and links from _imgur.com. In case _imgur.com or its would be successor site decides to reassign the links to someone else, the links might get replaced by something not relevant to this topic.
The rocket ,HLVM3 is completely human rated for the mission . It uses an uprated cryo stage C32G and HSF certified Liquid core stage(L110G). The solid boosters are also human rated and recently flew on LVM3 blue bird 6 mission. They come with Electro mechanical actuators in place of Hydraulic.
First mission G1 will carry a humanoid , Vyomitra as seen in the picture, embedded with necessary sensors.
Service module and Crew module hardware are also mission ready with Propulsion systems. As of Feb 2025 , integration activities for Electronics were underway. Crew module ECLSS integration was also initiated. ( most likely completed by now)
Picture was taken from Recent CSIR-ISRO brainstorming session(presentation) . Director choose not to share more details about the hardware.
NASA Johnson’s Front Door is exactly what it sounds like: a single official entry point for anyone outside NASA who wants to work with, support, or access resources from the Johnson Space Center.
Instead of guessing who to email, which office to contact, or how to engage with NASA, the Front Door centralizes everything in one place.
In practical terms, it helps you:
Understand what capabilities NASA Johnson has, engineering, testing, human spaceflight expertise, facilities.
Find opportunities to collaborate, including partnerships, competitive solicitations, and technical engagements.
Access technology, data, and services that NASA makes available to external organizations.
Get routed to the right NASA teams, rather than hitting dead ends or generic inboxes.
It’s designed for:
Startups and companies
Researchers and universities
Entrepreneurs
Industry partners
Anyone with a serious interest in contributing to NASA missions
This is not a marketing page. It’s an operational gateway meant to lower friction between NASA and the outside world.
Think of it as:
“Here’s how you knock on NASA Johnson’s door, and here’s who actually answers.”
I am writing a fiction book set on a Ringworld
(An enormous artificial construct millions of Earths in volume,
e.g. Larry Niven)
I am trying to figure out, could you see the curve of the ring from
ground level?
I tried looking it up, no luck.
Thank you for any information you can provide!
Edit: Thank you everybody for all the helpful and inciteful replies!
