Tag: exploration

Modeling says the Small Magellanic Cloud passed through the Large Magellanic Cloud 200 million years ago

11:18 am

Illustration of collision of Magellanic clouds
Click for original graphic.

According to new computer modeling, some astronomers now believe that a collision between the Small Magellanic Cloud (SMC) and the Large Magellanic Cloud (LMC) 200 million years ago best explains the chaotic movement of the stars in the former.

The SMC contains more mass in gas than in stars. Gas cools, contracts under gravity and settles into a rotating disk, the same process that shaped the spinning plane of our solar system. But when researchers, including those at University of Arizona, previously measured the motion of the SMC’s stars using the Hubble Space Telescope and the Gaia satellite of the European Space Agency, the SMC’s stars were not orbiting around the galaxy’s center the way stars in most galaxies do.

The possible reason, Rathore said, is a collision. A few hundred million years ago, the SMC crashed directly through the LMC’s disk. The LMC’s gravity disrupted the SMC’s internal structure and sent its stars into random, disordered motion. Also, the LMC’s gas applied a tremendous amount of pressure to the SMC’s gas and destroyed its gas rotation.

The graphic to the right illustrates that collision, based on the computer modeling. It appears the Small Magellanic Cloud’s passage through the Large Magellanic Cloud acted to shake the smaller cloud apart, spreading its stars and gas across a wider space.

You can read the paper here [pdf]. There is of course a great deal of uncertainty in these results, but they add weight to the general theory that galaxy formation is strongly impacted by such collisions. As the scientists note in the conclusion of their paper, “The SMC gives a front row view of group processes driving dramatic morphological and kinematic transformations.”

0 comments

The first Artemis lunar landings might not go to the Moon’s south pole

10:09 am

It appears from remarks recently by one NASA official, that while the south pole remains the agency’s main lunar base target, it is now looking into other landing options in order to make those first manned landing less risky and easier and quicker to achieve.

Amit Kshatriya, NASA Associate Administrator was very vague in his statement, but nonetheless this was what it appears he was saying:

We have opened up the, I would say, the performance specification for the early landing missions in as many ways as we can, in terms of different lunar orbits we want to take, or different other constraints … to make it as agile as possible, to recognize performance limitations in some of the machines we have and let our providers tell us, hey, if you took these constraints out of the way, how could we go faster? So we’re going to do that.

The agency’s administrator, Jared Isaacman, is also pushing to quickly begin sending a lot of unmanned landers to the south pole by next year. Thus, under this plan, we might actually find out first whether there really is water in those permanently shadowed craters, before committing our manned lunar base to this location.

This new approach makes a great deal of sense, especially since the data that has looked into those craters has been very inconclusive, some positive and some negative.

33 comments

Continuing our tour of Uranus’ five biggest moons: Ariel

12:17 pm

In preparing my cool image last week focused on the best Voyager-2 image of Uranus’ moon Miranda, I came to a realization that was somewhat startling. Voyager-2 is the only time a human spacecraft has gotten close to Uranus, and it was only close for a few days. Thus, the data and images it obtained of the gas giant and its moons is remarkable more sparse than I had ever realized.

You see, when these images were first released in 1986 they were exciting because they gave us that first look. Suddenly, a light was shined on something that had always been shrouded in darkness. It was a flood of data that needed processing.

It is now forty years later. No spacecraft has been there since, and thus we have gotten no more close-up information about Uranus or its moons. Data from Hubble and Webb has helped increase our knowledge of the planet itself, but of the moons nothing really new has been gleaned from this distance.

Uranus' five biggest moons

And so, to highlight how little we know, for the rest of this week I am going give my readers a tour of the few images Voyager-2 gave us of Uranus’ five biggest moons, the five that early astronomers had discovered prior to the space age and shown in the five pictures above, taken by Voyager-2 as it was approaching Uranus from a distance of about three million miles. They are, in order going from closest to farthest from Uranus, Miranda, Ariel, Umbriel, Titania and Oberon, with the images above designed to show their approximate relative sizes.

I already highlighted the strange, patchwork surface of Miranda last week, the smallest of these moons. Below is a mosaic made from the four highest resolution images of 720-mile-wide Ariel, the next out from Uranus, taken from a distance of about 80,000 miles.
» Read more

3 comments

Astronomers discover a super-Earth-sized exoplanet covered by a molten ocean of lava

9:53 am

Using the Webb Space Telescope astronomers think they have identified a super-Earth-sized exoplanet, dubbed L98-59d and orbiting a red dwarf star about 35 light years away, that is covered by a very deep molten ocean of lava.

Their results reveal that the mantle of L98-59d is likely molten silicate (similar to lava on Earth), with a global magma ocean extending thousands of kilometres beneath. This vast molten reservoir allows the planet to store extremely large amounts of sulphur deep inside its interior, over geologic timescales. The magma ocean also helps L98-59d to retain a thick hydrogen-rich atmosphere containing sulphur-bearing gases such as hydrogen sulphide (H2S). Normally, this would be lost to space over time, due to X-ray radiation produced by the host star.

You can read the peer-reviewed paper here [pdf]. This planet is part of a three-planet solar system, all of which transit the face of the star, allowing for excellent observations of their make-up. L98-59d is the outermost of the three.

This is the first molten exoplanet yet detected, though it is likely not the last. As new better telescopes come on-line both on Earth and especially in space, the ability to make more detailed observations of the thousands of exoplanets so far identified is certain to reveal many more strange objects, some of which will be probably far stranger than we can yet imagine.

0 comments

Terran Orbital wins contract to build cubesat to go to Apophis with ESA’s Ramses probe

9:08 am

Apophis' path past the Earth in 2029
A cartoon (not to scale) showing Apophis’s
path in 2029.

The satellite company Terran Orbital, owned by Lockheed Martin, has won a contract from the European Space Agency (ESA) to build a cubesat to fly with its Ramses probe that will launch in 2028 and rendezvous with the potentially dangerous asteroid Apophis when it makes its very close fly-by of the Earth on April 13, 2029.

The CubeSat is named after Italian scientist Paolo Farinella and is backed by the Italian Space Agency. After successfully completing the Critical Design Review in January 2026, Tyvak International [a subsidiary of Terran Orbital] will begin the implementation phase, with launch currently planned for 2028.

…Operating aboard the RAMSES spacecraft, developed by OHB Italia, the Farinella CubeSat will be one of two spacecraft deployed to explore the asteroid’s subsurface using low-frequency radar. The satellite will also carry Horus, an optical instrument that acts as both a science imager and navigation camera, and Vista, a dust detector previously flown on the Milani CubeSat from ESA’s Hera mission.

Apophis is estimated to be about 1,200 feet across. When it does its fly-by in ’29 it will get within 20,000 miles of the Earth, dipping within the orbits used by geosynchronous satellites. It will then pass within 60,000 miles of the Moon. At its closest it will for a short time be visible to the naked eye.

Apophis’ orbit means that it has the potential in the next century or so to impact the Earth. This particular fly-by is significant because the Earth/Moon’s gravity will change the asteroid’s path in an unpredictable manner that could either increase or decrease that impact possibility on future fly-bys. And we won’t know until after the fly-by is complete.

1 comment

Miranda, the smallest of Uranus’ spherical moons

12:52 pm

Miranda as seen by Voyager-2
Click for original image.

Cool image time! The image to the right, reduced and sharpened to post here, was created from photographs taken on January 24, 1986 by Voyager-2 as it made its fly-by of the gas giant Uranus. From a later 1996 release:

Miranda, roughly 300 miles in diameter, exhibits varied geologic provinces, seen in this mosaic of clear-filter, narrow-angle images from Jan. 24, 1986. The images were obtained from distances of 18,730 to 25,030 miles; resolution ranges from 1,840 to 2,430 feet. These are among the highest-resolution pictures that Voyager has obtained of any of the new “worlds” it has encountered during its mission.

On Miranda, ridges and valleys of one province are cut off against the boundary of the next province. Probable compressional (pushed-together) folded ridges are seen in curvilinear patterns, as are many extensional (pulled-apart) faults. Some of these show very large scarps, or cliffs, ranging from 1,600 feet to 3 miles in height — that is, higher that the walls of the Grand Canyon on Earth.

This is really the only close look we have of this distant world. The other hemisphere remains a mystery, as it was in darkness when Voyager-2 zipped past. And though some of the individual shots that make up this mosiac are more detailed, they don’t provide that much more information.

Nonetheless, to my uneducated eye Miranda looks like a ball of thick molasses that some giant stirred a bit as gravity forced it to settle into its spherical shape. In this case the molasses is likely a mix of ice and other materials, not yet fully identified. The result is a tiny misshapen planet with some of the roughest topography known in the solar system, including one 12-mile high cliff face (the white streak at the image bottom) thought to be the highest in the solar system.

We don’t yet have a true understanding of the geological processes that formed this strange landscape, nor will we have until we have a lot more data, including a global map of the entire surface. And that won’t come until a spacecraft is sent there to look more closely. Right now no such mission is in the works. No NASA missions have been funded, though several have been proposed. And a Chinese mission was apparently canceled last year.

2 comments

China to begin construction of its Mars sample return spacecraft

8:13 am

China’s state-run press today announced it is about to begin construction of its Mars sample return spacecraft, Tianwen-3, set for launch in 2028.

Based on the announcement, that date seems very unlikely.

China’s mission to retrieve samples from Mars will advance to the flight model development phase within this year, Liu Jizhong, chief designer of the Tianwen-3 mission, said on Thursday. Building on the preliminary technical research and demonstrations, the mission has achieved breakthroughs in key technologies. The engineering team is now focused on developing prototypes, Liu, also a national legislator, told reporters.

The Mars sample return mission is scheduled for launch around 2028, with the goal of returning no less than 500 grams of Martian samples to Earth by around 2031. [emphasis mine]

They only have two years to get the spacecraft built, and it involves “an orbiter, a returner, a lander, an ascender, and a service module.” While China is basing this mission’s design on its successful Chang’e lunar sample return missions, returning samples from Mars is significantly more challenging. The ascent vehicle will have a much greater gravity to overcome, and doing a robotic rendezvous and docking in orbit around another planet millions of miles from Earth has never even been tried.

3 comments

Cubesat ultraviolet space telescope achieves first light

5:05 pm

Sparcs first light images
Click for original images.

A new low-cost cubesat-sized NASA ultraviolet space telescope, dubbed Sparcs, has achieved first light, successfully taking both near- and far-ultraviolet false-color images of a nearby star.

Those images are to the right, with the top the far-ultraviolet image and the bottom in the near ultraviolet. From the press release:

Roughly the size of a large cereal box, SPARCS will monitor flares and sunspot activity on low-mass stars — objects only 30% to 70% the mass of the Sun. These stars are among the most common in the Milky Way and host the majority of the galaxy’s roughly 50 billion habitable-zone terrestrial planets, which are rocky worlds close enough to their stars for temperatures that could allow liquid water and potentially support life.

The question astronomers will try to answer with this telescope is whether the solar activity on these stars is high enough to prevent life from forming in the star’s habitable zone. Because these stars are dim and small, the habitable zone is quite close to the star, which means solar activity has a higher impact on the planet. We don’t yet have sufficient data to determine the normal activity of such stars. Sparcs will provide a good first survey.

It will also demonstrate the viability of such small low-cost cubesats for this kind of research. If successful expect more such telescopes, some of which are likely to be private, like Blue Skies Space’s Mauve optical telescope already in orbit.

0 comments

A close-up of the dark side of Saturn’s moon Iapetus

11:55 am

Iapetus' equator ridge
Click for original image.

Cassini's first global close-up of Iapetus
Click for original image.

Today’s cool image is a double-header! The picture above, cropped to post here, was taken on September 10, 2007 during Cassini’s fly-by of Saturn’s moon Iapetus, taken from approximately 1,000 miles above the surface. It looks at the dark side of this two-toned planet (see yesterday’s cool image). As the moon’s rotation is tidally locked so that one side always faces Saturn, one hemisphere always leads while the other always trails. For some reason still unexplained, the leading hemisphere is covered with an almost pitch-black material, while the trailing hemisphere is bright and very white, its icy surface quite visible.

For context, to the right is a global image of that dark side taken during Cassini’s first fly-by of Iapetus on December 31, 2004. This picture highlights the long ridge that runs along the planet’s dark hemisphere’s equator that was the focus of the close-up image above. From the 2005 press release:

The most unique, and perhaps most remarkable feature discovered on Iapetus in Cassini images is a topographic ridge that coincides almost exactly with the geographic equator. The ridge is conspicuous in the picture as an approximately 12 miles band that extends from the western (left) side of the disc almost to the day/night boundary on the right. On the left horizon, the peak of the ridge reaches at least 8 miles above the surrounding terrain. Along the roughly 800-mile-length over which it can be traced in this picture, it remains almost exactly parallel to the equator within a couple of degrees. The physical origin of the ridge has yet to be explained. It is not yet clear whether the ridge is a mountain belt that has folded upward, or an extensional crack in the surface through which material from inside Iapetus erupted onto the surface and accumulated locally, forming the ridge.

Iapetus itself has a diameter of about 900 miles, so this ridge essentially crosses most of the dark hemisphere.

The 2007 press release did not provide enough information to pinpoint exactly where along that ridge the close-up is located, but no matter. Both images make very clear what we are looking at.

11 comments

Have astronomers spotted the collision of two exoplanets around a Sunlike star?

9:36 am

Changes in the infrared

Using data from a number of orbiting space telescopes, astronomers think they have detected the collision of two exoplanets, producing debris that for about 200 days variably blocked the light from the system’s star.

The images to the right come from figure 1 of their published paper [pdf], showing changes in the infrared as detected by the WISE space telescope. From the press release:

The star, named Gaia20ehk, was about 11,000 light-years from Earth near the constellation Pupis. It was a stable “main sequence” star, much like our sun, which meant that it should emit steady, predictable light. Yet this star began to flicker wildly. “The star’s light output was nice and flat, but starting in 2016 it had these three dips in brightness. And then, right around 2021, it went completely bonkers,” said Tzanidakis, a doctoral candidate in astronomy at the University of Washington. “I can’t emphasize enough that stars like our sun don’t do that. So when we saw this one, we were like ‘Hello, what’s going on here?’”

The cause of the flickering had nothing to do with the star itself: Huge quantities of rocks and dust — seemingly from out of nowhere — were passing in front of the distant star as the material orbited the system, patchily dimming the light that reached Earth. The likely source of all that debris was even more remarkable: a catastrophic collision between two planets.

…“The infrared light curve was the complete opposite of the visible light,” Tzanidakis said. “As the visible light began to flicker and dim, the infrared light spiked. Which could mean that the material blocking the star is hot — so hot that it’s glowing in the infrared.”

A cataclysmic collision between planets would certainly produce enough heat to explain the infrared energy. What’s more, the right kind of collision could also explain those initial dips in light.

The data suggests the collision occurred at an orbit comparable to that of the Earth’s, and took more than a half a year to largely dissipate.

All of this is a reasonable hypothesis based on the data available. Though there is a lot of uncertainty in this conclusion, the researchers considered other explanations, such as variability in the star itself, and found them less credible.

1 comment

Iapetus: Saturn’s ying-yang moon

11:55 am

Iapetus as seen by Cassini in 2007
Click for original image.

Cool image time! The image to the right, reduced and sharpened to post here, was taken on September 10, 2007 by the Saturn orbiter Cassini as it made its first close fly-by of the moon Iapetus, from a distance of about 45,000 miles.

Iapetus, about 912 miles in diameter, is one of the strangest objects in the solar system. As it orbits Saturn, its leading hemisphere is very dark, covered with almost pitch black material, while its trailing hemisphere is very bright. This picture captures a bit of both, with the dark leading hemisphere visible along the right edge.

In many places, the dark material–thought to be composed of nitrogen-bearing organic compounds called cyanides, hydrated minerals and other carbonaceous minerals–appears to coat equator-facing slopes and crater floors. The distribution of this material and variations in the color of the bright material across the trailing hemisphere will be crucial clues to understanding the origin of Iapetus’ peculiar bright-dark dual personality.

There are several theories to explain the planet’s strange ying-yang two-tone coloration. One suggests it is material thrown off by other Saturn moons that Iapetus sweeps up. Other theories suggest the planet’s orbit itself causes the two hemispheres to have different temperatures, allowing material to sublimate off the dark side and to the bright side.

No theory is presently accepted. Nor does any explain the data fully.

Tomorrow I’ll post a most intriguing close-up of Iapetus taken by Cassini during that 2007 fly-by.

0 comments

Interstellar comet 3I/Atlas is unusually enriched with windshield wiper fluid

10:45 am

New Hubble image of 3I/Atlas
Comet 3I/Atlas as seen by Hubble
in November 2025. Click for original.

While interstellar comet 3I/Atlas is remarkably like most comets from our own solar system, scientists have now found new evidence that it spalled off unusual amounts of methanol (CH3OH) — material normally used as windshield washer fluid, carburetor fluid, and cooking fuel — when it made its close fly-by of the Sun in the fall of 2025.

You can read the paper here [pdf] . The research also detected large amounts of prussic acid (HCN). As the comet made its closest pass to the Sun, the numbers increased. From the paper’s abstract:

The CH3OH production rate increased sharply from August through October, including an uptick near the inner edge of the H2 O sublimation zone at r H = 2 au. Compared to comets measured to date at radio wavelengths, the derived CH3 OH/HCN ratios in 3I/ATLAS of 124+30 −34 and 79−14 +11 on September 12 and 15, respectively, are among the most enriched values measured in any comet, surpassed only by anomalous solar system comet C/2016 R2 (PanSTARRS).

Though the numbers are high, they aren’t outside the range of what has been found in comets from our own solar system. Instead, this data suggests — as has all data so far — that Comet 3I/Atlas is a normal comet, but unique in its own way, as are all comets and in fact every object in space.

4 comments
1 … 4 5 6 7 8 … 89