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Jason Major Profile picture
Jason Major
@JPMajor
Sharing awesome news and amazing views of our fascinating Universe.
Feb 5, 2022 • 5 tweets • 3 min read
Distances on the Moon can be difficult to discern visually. In this black and white photo (AS14-68-9486) taken 51 years ago during EVA 2 of Apollo 14 the LM Antares and Shepard are about 100 meters away; the large 1km-wide crater (Old Nameless) on the horizon is 2.6 km away! The crater visible in front of Old Nameless, one of the Triplet craters, is only about another 100 meters beyond Shepard. This photo was taken by Ed Mitchell from Station H. (I adjusted contrast and cleaned up some vertical streaks in the sky area and removed the Réseau marks.)
Feb 5, 2022 • 5 tweets • 2 min read
Alan Shepard's golf ball and Ed Mitchell's makeshift javelin, left on the Moon after the Apollo 14 "lunar #Olympics" on February 6, 1971. (Crop of NASA photo AS14-66-9337) This is the golf club Shepard used on the Moon to drive his ball "miles and miles"
Feb 4, 2022 • 7 tweets • 3 min read
Fact: the Moon's orbit around Earth isn't a perfect circle but rather elliptical, and so over the course of each orbit the Moon's distance from Earth varies from about 356,400 km (221,460 miles) to 406,700 km (252,700 miles); these also vary a bit over the course of a full year. Also while the Moon always keeps the same side aimed toward Earth—a common scenario among moons called tidal locking—it's also not perfect because the Moon's axis is tilted relative to its orbital plane. This causes a slow wobbling effect called libration.
Jun 30, 2021 • 4 tweets • 2 min read
113 years ago today something exploded above the bogs of Siberia, flattening trees for over 800 square miles but leaving no obvious crater: the “Tunguska Event.” It’s thought to have been an asteroid or comet but neither has been conclusively determined. lightsinthedark.com/2016/06/30/we-… Space artist Don Davis @DDAVISSPACEART posted this illustration last year of what probably occurred in the atmosphere during the event:
Jun 29, 2021 • 7 tweets • 3 min read
“For the first time ever, astronomers have detected the scariest thing in the Universe eating the second scariest thing: A black hole devouring a neutron star.” ⁦@BadAstronomer⁩ on ⁦⁦@SYFYWIRE⁩ syfy.com/syfywire/space… Please note this is a gravitational wave detection, not an optical/electromagnetic observation.
Feb 19, 2021 • 6 tweets • 3 min read
This is the first high-definition color image (uncalibrated, screenshot) of Perseverance's landing site, taken after the dust cover was removed. #Mars2020 Another color image from a different camera shows the ground near the rover's wheel. #Mars2020
Feb 19, 2021 • 6 tweets • 4 min read
These are top-down views of @NASAPersevere's landing site—the white circle—made from a @HiRISE image (uahirise.org/ESP_046060_1985) captured in May 2016. Recolored from greyscale; north on Mars is up. #Mars2020 ImageImage Séan Doran also made some nice renderings of Perseverance's position after landing from digital terrain data
Feb 18, 2021 • 6 tweets • 2 min read
Colorized versions of the screen captures of @NASAPersevere's first images after its successful landing on Mars #CountdownToMars ImageImage I've got some Mars color presets in Photoshop to make greyscale images into something sort of like natural lighting, so I just applied them here to the screen shots.
Feb 17, 2021 • 6 tweets • 3 min read
Jezero Crater, the future home of #Perseverance, is about 28 miles (45 km) across. There's an obvious river delta formation inside its western rim, and that's where the rover is going. Here's a close-up of part of the fascinating landscape within the target #Perseverance landing and exploration area in Jezero, captured by the @HiRISE camera aboard NASA's MRO in July 2014. (Colored cropped and original map-projected monochrome versions.) ImageImage
Jan 28, 2021 • 6 tweets • 3 min read
When you look up at the Moon (today is a full Moon, like the one here from Nov. 29) you can think about the comparative sizes of the moons on Mars, which are much smaller but orbit much closer. These are how Phobos and Deimos would look from Mars' surface, compared to our Moon. Earth's Moon is 2,158 miles / 3,473 km wide and around 238,000 miles / 383,000 km away.

Phobos is only 16.7 miles / 27 km wide but also only 3,721 miles / 5,989 km away from Mars.

Deimos is 15 km / 9.3 miles at its widest and orbits Mars 14,580 / 23,460 km away.
Oct 14, 2020 • 9 tweets • 3 min read
There's an estimated 10% chance that two large pieces of orbiting space debris could collide tomorrow night at an altitude of 615 miles and a relative velocity of 32,883 mph. With a combined mass of over three tons, these two orbiting objects will miss each other by about 40 feet.😬

Let's hope we don't add Kessler syndrome to the list of 2020 fun
Apr 20, 2019 • 5 tweets • 2 min read
Cool 3D rendering of the Milky Way galaxy by @StefanPWinc showing the curve of the galactic plane and dust using data from GAIA (ht @runnymonkey) The galaxy our Sun and solar system resides within is a barred spiral galaxy about 105,700 light-years across. Its plane is not a perfectly flat disk though; astronomers have found that it has a warped shape. earthsky.org/space/milky-wa…
May 31, 2018 • 12 tweets • 5 min read
This image shows the limb of Saturn's moon Iapetus, captured by #Cassini on Sept. 10, 2007. A ridge of 10km-high (6.2 mile) mountains encircles the equator, possibly the remains of a former satellite that broke apart as its orbit degraded. Iapetus is 1,470 km (913 miles) wide. Here's a wide-angle view of Iapetus from the same observation set on 9/10/07. Color comp made from images acquired in IR, G, and UV.