r/Mars

Although gullies are most common in the middle latitudes of Mars, they are also found in equatorial regions. This image shows a 3-kilometer-wide impact crater with gullies all along the steep inner slopes.

An enhanced-color cutout better distinguishes the gully deposits from the surrounding boulder fields. These slopes are very steep, so a fluid like water is not required to explain gully formation.

ID: ESP_035945_1755

date: 28 March 2014

altitude: 262 km

https://uahirise.org/hipod/ESP_035945_1755

NASA/JPL-Caltech/University of Arizona

The drainages in this image are part of Hebrus Valles, an outflow channel system likely formed by catastrophic floods.

Hebrus Valles is located in the plains of the Northern Lowlands, just west of the Elysium volcanic region. Individual channels range from several hundred meters to several kilometers wide and form multi-threaded (anastamosing) patterns. Separating the channels are streamlined forms, whose tails point downstream and indicate that channel flow is to the north. The channels seemingly terminate in an elongated pit that is approximately 1875 meters long and 1125 meters wide. Using the shadow that the wall has cast on the floor of the pit, we can estimate that the pit is nearly 500 meters deep.

The pit, which formed after the channels, exposes a bouldery layer below the dusty surface mantle and is underlain by sediments. Boulders several meters in diameter litter the slopes down into the pit. Pits such as these are of interest as possible candidate landing sites for human exploration because they might retain subsurface water ice that could be utilized by future long-term human settlements.

ID: ESP_048036_2025

date: 25 October 2016

altitude: 286 km

https://uahirise.org/hipod/ESP_048036_2025

NASA/JPL-Caltech/University of Arizona

In this observation, within the Shalbatana Vallis outflow channel, there appears to be relict fan-shaped deposits towards the top of the channel wall. These surfaces appear perched on top of a mesa-like-feature suggesting erosion of their margins. Surrounding this feature are younger deposits and areas of chaotic terrain. This image can help to evaluate their stratigraphic relationships to the younger fans and the chaotic terrain/wider channel formation.

ID: ESP_092944_1805

date: 25 May 2026

altitude: 269 km

https://uahirise.org/hipod/ESP_092944_1805

NASA/JPL-Caltech/University of Arizona

credit - space_facts7

Juventae Chasma, just north of Valles Marineris, is notable for several reasons: it is an otherworldly size-box canyon, and shares a name with the mythological Fountain of Youth.

This image, from Juventae Chasma’s southern extent, captures the extraordinary visual softness of the sand on the bottom of the canyon. Unlike other places in Juventae Chasma where ripples and more bedrock landforms are visible, in this scene we can identify peaks arising from a base of smooth materials.

​Rather than the sand being grouped in well-behaved, Star-Trek-communicator-badge-shaped barchan dunes, the sand blankets the full surface below the two peaks captured here. The source of this sand is linked to the chasma’s complex geologic history, which likely includes a combination of icy, watery, and windy processes.

ID: ESP_092391_1755

date: 12 April 2026

altitude: 269 km

https://uahirise.org/hipod/ESP_092391_1755

NASA/JPL-Caltech/University of Arizona

A great info graphic about the 3 Viking Lander life detection experiments was the centerfold in the article "Sifting for Life in the Sands of Mars" by Rick Gore in National Geographic January 1977 edition, Vol.151 No.1. The trinity: Pyrolytic Release Experiment (PR, PI Dr. Norman Horowitz, Caltech), Labeled Release Experiment (LR, PI Dr. Gilbert Levin, Biospherics Inc.), Gas Exchange Experiment (GEX, PI Dr. Vance Oyama, NASA Ames Research Center). I got the original old edition on ebay recently.

The primary biological barriers include insufficient atmospheric pressure, which causes bodily fluids to boil, and high radiation exposure due to the lack of a protective magnetic field and thick atmosphere.

*Gravity Issues*: Mars has only 38% of Earth's gravity; no vertebrate has successfully completed fetal development or birth in low-gravity environments, posing a fundamental barrier to human reproduction. 

*Radiation Damage*: Without Earth’s magnetic shield, colonists would absorb lethal doses of cosmic and solar radiation, causing severe DNA damage and high cancer risks. 

*Respiration and Pressure*: The thin atmosphere consists mostly of carbon dioxide, offering no breathable oxygen and insufficient pressure to keep blood and saliva in liquid form. 

*Evolutionary Limits*: Natural selection cannot occur fast enough to adapt humans to these conditions, as exposure to the surface is immediately fatal. 

While terraforming proposals exist to warm the planet and thicken the atmosphere, scientific consensus indicates there is not enough accessible carbon dioxide to make Mars habitable in the foreseeable future.  

Source:

https://www.nhm.ac.uk/discover/news/2018/july/its-official-we-cant-terraform-mars.html

https://www.space.com/entertainment/space-movies-shows/can-you-really-survive-on-mars-what-science-fiction-gets-wrong-about-off-world-living

https://www.sciencefocus.com/space/could-humans-evolve-to-adapt-to-mars

We’ve imaged thousands of new impact sites. These are locations with before and after images constraining when the impact happened. We are especially interested in craters that expose shallow ice, which appears as especially bright and relatively blue material.

The new impact imaged here looks like such a crater, but it formed at 3.5 North latitude, almost exactly on the equator, where shallow ice is highly unstable to loss by sublimation. There is also regolith that is bright and relatively blue, perhaps material altered by hot springs or fumaroles. This crater may have revealed an interesting deposit that was hidden by dust. We will monitor this crater over time to see if it fades rapidly as expected for ice.

ID: ESP_092110_1835

date: 21 March 2026

altitude: 267 km

https://uahirise.org/hipod/ESP_092110_1835

NASA/JPL-Caltech/University of Arizona

"Flight" over Holden Crater on Mars

Based on data from the High Resolution Stereo Camera (HRSC) on Mars Express

HRSC / ESA / DLR / FU Berlin / Seán Doran

https://bsky.app/profile/theseaning.bsky.social/post/3mp4urud62s23

Raw image

This image was taken by Left Navigation Camera onboard NASA's Mars rover Curiosity on Sol 4932 (2026-06-21 15:06:32 UTC).

Credits: NASA/JPL-Caltech​

https://mars.nasa.gov/raw_images/1604495/?site=msl

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NASA/JPL-Caltech/MSSS/fredk/S Atkinson

https://bsky.app/profile/stuartatkinson.bsky.social/post/3mpg7bbsrkk2o

This image was taken by Right Navigation Camera onboard NASA's Mars rover Curiosity on Sol 4931 (2026-06-20 21:25:30 UTC).

Credits: NASA/JPL-Caltech

https://mars.nasa.gov/raw_images/1603758/?site=msl

https://bsky.app/profile/ridingrobots.bsky.social/post/3mphbpzu4n226

Hebrus Valles are a complex set of channels in the northern lowlands of Mars just to the west of the Elysium volcanic region.

The channel segments to the north of this image display a variety of features, including streamlined forms and terracing that are suggestive of catastrophic flooding.

However, this observation shows channels of uniform width suggesting more persistent flows eroding into and around two impact craters, each about 200 hundred meters in diameter. This complex geology may be the result of formation in volcanic terrains as fluid flows erode into basalt and interbedded ash or sediment layers. The channel system is thought to be early Amazonian in age (as far back as 3 billion years ago), which is younger than many of the other outflow channels on Mars.

ID: ESP_074187_2010

date: 24 May 2022

altitude: 286 km

https://uahirise.org/hipod/ESP_074187_2010

NASA/JPL-Caltech/University of Arizona

The feeling I get is that it would maybe look like the Redline from One Piece, or potentially look like it goes on indefinitely into space

This area is potentially useful for monitoring the wind-generated processes of Hershel Crater. This gorgeous dune field near the center of the image target. HiRISE images have demonstrated that the dunes are not stationary, but have moved over time, so multiple images help to track those changes over time. The crater is jointly named after the 17th/18th century father and son astronomers William Herschel and John Herschel.

ID: ESP_077062_1660

date: 3 January 2023

altitude: 257 km

https://uahirise.org/hipod/ESP_077062_1660

NASA/JPL-Caltech/University of Arizona

As above so below, the Perseverance Rover tracks are visible. 1900 Mars days (sols) now on the surface yesterday, 24 June 2026!

The 2nd image was taken by Mars Reconnaissance Orbiter 10 days ago and shows the rover from 300 km above. That's only possible with a clear atmosphere, like the sky seen from ground also shows.

Navcam / Watson images: https://areo.info/mars20/ecams/1900/ and even better with the areoHDR app

2nd image: PIA26726 from https://jpl.nasa.gov/images/pia26726-nasas-hirise-captures-perseverance-marking-a-milestone-on-mars/