Category: Behind The Black

Finding ways to clean ISS and future interplanetary spaceships

9:33 am

Fungi on ISS

According to multiple studies (see here, here, and here), a whole range of microorganisms, from bacteria (some dangerous) to fungi, have been found prospering on ISS.

The photo to the right shows a typical example of fungi growing on one of ISS’s older surfaces.

A European Space Agency (ESA) project is attempting to developing new coatings that will not only protect surfaces but act to clean them as well.

“With astronauts’ immune systems suppressed by microgravity, the microbial populations of future long-duration space missions will need to be controlled rigorously,” explains ESA material engineer Malgorzata Holynska. “So ESA’s Materials’ Physics and Chemistry Section is collaborating with Istituto Italiano di Tecnologia, IIT, to study antimicrobial materials that could be added to internal cabin surfaces.”

The IIT team has begun work on titanium oxide, also known as ‘titania’, used for example in self-cleaning glass down here on Earth, as well as in hygienic surfaces. When titanium oxide is exposed to ultraviolet light, it breaks down water vapour in the air into ‘free oxygen radicals’, which eat away whatever is on the surface, including bacterial membranes. “Bacteria gets inactivated by the oxidative stress generated by these radicals,” says Mirko Prato of IIT. “This is an advantage because all the microorganisms are affected without exception, so there is no chance that we increase bacterial resistance in the same way as some antibacterial materials.”

The application however is not as simple as painting the surface. Right now they wish to keep this coating as thin as possible (“50 to 100 nanometres, millionths of a millimetre”) so that it could even be applied to clothing, which requires using complex techniques similar to those used to make semi-conductors.

Though hand cleaning would likely be much simpler and cheaper, there are issues. First, it isn’t as easy to scrub a surface by hand in weightlessness. Second, in a closed environment like ISS cleaning materials pose a greater hazard to both the occupants and the equipment. Better if the surfaces of equipment and clothing are designed to stay clean, on their own.

10 comments

Software issues delay Psyche launch seven weeks

9:05 am

Engineers preparing to stack the Psyche probe on top of its Falcon Heavy rocket for an August 1, 2022 launch have been forced to delay that launch at least seven weeks until September 20th at the earliest because of a software issue.

Technicians unboxed the Psyche spacecraft and moved it to a handling fixture for a series of hardware and software tests to make sure the probe survived the cross-country trip from California.

But a technical issue interrupted the test campaign, and will delay the launch of the Psyche mission at least seven weeks.

“An issue is preventing confirmation that the software controlling the spacecraft is functioning as planned,” NASA said in a written statement, responding to questions from Spaceflight Now. “The team is working to identify and correct the issue.”

Assuming no further delays, the spacecraft will still reach Psyche in January 2026.

2 comments

Mars: Are these eroding glaciers or impacts in lava?

1:38 pm

Eroding lava or glaciers?
Click for original image.

Cool image time and a mystery! The photo to the right, cropped to post here, was taken on March 29, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO) of an 18-mile-wide crater in the southern cratered highlands of Mars. The full picture, dubbed “Steep Cliff,” was taken apparently to get a good view of the crater’s northern rim. The rim’s steepness suggests that the floor of the crater is significantly filled.

More intriguing however are the scattering of strange depressions about six miles south of the rim. What caused them? The crater’s location is in a part of Mars where it is not unusual to find both glacial features as well as flood plain lava. In fact, the crater’s northeast and southwest rims appear to have been buried by what appears to be flood lava. The northern rim’s shallowness also suggests the crater is well filled with flood lava.

However, the crater is also at 38 degrees south latitude, a latitude where planetary scientists have found lots of glacial features. Much of this crater fill could be glacial.

The overview map below illustrates this mystery.
» Read more

One comment

Pushback: Professor fired for having opinions wins total victory

11:59 am

University of Central Florida: Hostile to free speech
University of Central Florida: Hostile to free speech

Bring a gun to a knife fight: In January 2021 (in one of my first blacklist columns and just after Biden assumed power), I described how professor Charles Negy was fired from the teaching job he had had at the University of Central Florida for 22 years, merely because he had stated some obvious facts about BLM and affirmative action on his twitter feed.

The school claimed it did not fire him for these tweets (an obvious lie based on the events), but because of a supposed pattern of inappropriate classroom behavior obtained through anonymous tips, tips instigated by Negy’s tweets that by the way did not match any of the school’s previous assessments of his teaching.

Negy fought back, demanding his case be reviewed by an independent arbitrator, and has now won his case.

In the ruling on Monday, the arbitrator, Ben Falcigno, found that the university had failed to show “just cause” when it fired Dr. Negy because it had not given him a chance to change his conduct in the classroom or, alternatively, to show that he was incapable of changing his behavior.
» Read more

6 comments

SpaceX seeking another $1.725 billion in investment capital

9:07 am

Capitalism in space: SpaceX has begun another private funding round, now asking for $1.725 billion in new investment capital.

The space venture is looking to bring in up to $1.725 billion in new capital, at a price of $70 per share, according to a company-wide email on Friday obtained by CNBC. Notably, SpaceX split its stock price 10-for-1 in February, which reduced the common stock to $56 a share – with the new valuation representing a 25% increase.

When added to past funding rounds — and including the $2.9 billion provided by NASA for turning Starship into a manned lunar lander — SpaceX will have raised approximately $12 billion total for building Starship.

Sounds like a lot, doesn’t it? Well, compared to what NASA has spent for its expendable SLS rocket (about $60 billion), $12 billion is chicken feed, especially because Starship will not be expendable, but entirely reusable.

If this contrast doesn’t illustrate the strength of freedom, competition, and private enterprise over government, I don’t know what does. Government, not caring about making a profit, produces a disposable rocket costing many billions, and takes two decades to do it. Private enterprise in comparison also wants a big rocket, but it also doesn’t look kindly on throwing away its investment with each launch. It instead insists the cost to build it be constrained, as well as the time to do it.

The result: Government accomplishes little and wastes a lot. Private enterprise makes it happen, and quickly for a reasonable cost.

7 comments

Boeing uninterested in finding customers for Starliner outside of NASA?

8:54 am

Capitalism in space: According to a story yesterday, Boeing, ULA, and NASA plan on launching Starliner through the end of the decade on the last few Atlas-5 rockets in existence, which in turn suggests that Boeing is either not looking for any Starliner customers outside of NASA or has none.

With NASA planning to alternate between Boeing’s Starliner and SpaceX’s Crew Dragon for International Space Station crew rotation missions once Starliner is certified, each flying once a year, it implies that Atlas 5 launches of Starliner could continue well into the latter half of the decade. ULA, which has stopped selling Atlas 5 launches, has previously discussed phasing out Atlas 5 in favor of Vulcan Centaur around the middle of the decade.

…Even at a pace of one mission a year, though, and with no other customers for Starliner, the supply of Atlas vehicles would be exhausted before the projected retirement of the ISS in 2030. “We would look, toward the end of the decade, to award other flights, or have other flights potentially for Boeing,” said Steve Stich, NASA commercial crew program manager. “We would look for a new system.” He added NASA would support human-rating a new system “when Boeing and ULA are ready.” [emphasis mine]

The implications of the story is that Boeing is simply not interested in finding other customers for Starliner, nor is it trying to find alternative launch vehicles to replace the Atlas-5. Instead, the company has simply calculated that there are enough Atlas-5s left to complete its obligations to NASA, and that is all it needs. Competing for additional commercial manned space flights does not interest it.

It also appears that only when NASA demands or needs another launch vehicle will Boeing and ULA make an effort to replace Atlas-5.

All in all, this does not speak well for the future of either Boeing or ULA. A lack of competitive spirit will quickly leave you in the dust, especially if a host of new startups exist to grab your market share. Either both companies change their attitudes, or both will die.

17 comments

Mitsubishi develops technology to 3D print cubesat antennas in space using sunlight

9:22 pm

Capitalism in space: Mitsubishi this week announced a new technology it had developed that will allow small cubesats to 3D print antennas in space much larger than the satellite itself, using the sun’s ultraviolet radiation to harden the resin.

The full press release can be read here [pdf].

– On-orbit manufacturing eliminates the need for an antenna structure that can withstand vibrations and shocks during launch, which is required for conventional antenna reflectors, making it possible to reduce the weight and thickness of antenna reflectors, thereby contributing to the reduction of satellite weight and launch costs.

– Assuming the use of a 3U CubeSat (100 x 100 x 300 mm) specification, an antenna reflector with a diameter of 165 mm, which is larger than the size of the CubeSat bus, was fabricated in air, and a gain of 23.5 dB was confirmed in the Ku band (13.5 GHz).

Obviously this is still in development, but once viable commercially it will expand the capabilities of cubesats enormously, especially for interplanetary missions which need larger antennas for communications.

8 comments

Starliner successfully docks with ISS

5:38 pm

Starliner docked to ISS
Screen capture just after soft docking.

Boeing and NASA today successfully docked an unmanned Starliner capsule to ISS for the first time, completing the up-from-Earth portion of this demo mission to prove out this Boeing spacecraft as a future ferry to bring astronauts to and from the station.

The screen capture to the right, taken from the live feed, shows Starliner just after a successful soft capture docking. This was shortly followed by a hard dock.

They will open the hatch tomorrow after checking out the capsule’s linkage with ISS.

The docking itself was delayed by about 78 minutes, partly to time the docking during a period of good orbital communications and partly because of an issue with NASA’s own docking ring on the station that required engineers to reset it.

8 comments

A pair of spiral galaxies

2:02 pm

IC 4271, or AP 40, a pair of active galaxies
Click for full image.

Another cool image to herald in the weekend! The photo to the right, cropped and reduced to post here, was taken by the Hubble Space Telescope and shows a pair of spiral galaxies about 800 million light years away.

The smaller galaxy is superimposed on the larger one, which is a type of active galaxy called a Seyfert galaxy.

Seyfert galaxies are named for astronomer Carl K. Seyfert who, in 1943, published a paper about spiral galaxies with very bright emission lines. Today we know that about 10% of all galaxies may be Seyfert galaxies. They belong to the class of “active galaxies” – galaxies that have supermassive black holes at their centers accreting material, which releases vast amounts of radiation. The active cores of Seyfert galaxies are at their brightest when observed in light outside the visible spectrum. The larger galaxy in this pair is a Type II Seyfert galaxy, which means it is a very bright source of infrared and visible light.

In other words, both of these galaxies emit a lot of radiation in the infrared, radio, and X-rays due to activity taking place at the supermassive black holes believed to be at their cores.

5 comments

Dry flows on Mars?

1:50 pm

Flows in Orson Welles Crater
Click for original image.

Cool image time! The picture to the right, rotated, cropped, reduced, and annotated to post here, was taken on September 21, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO) and shows what appear to be a variety of flows, from alluvial fill to slope streaks to dust coming down the southeastern interior rim of 77-mile-wide Orson Welles Crater on Mars.

The location is almost right on the equator, so none of these flows are ice- or water-related. Nor are such flows unusual in the meandering 800-mile-long canyon that cuts through Orson Wells crater, dubbed Shalbatana Vallis. I featured similar flows at a spot to the north and downstream from this one in May 2021, also on the canyon’s eastern rim.

The overview map below provides some context.
» Read more

Leave a comment

Pushback: Five bowling alleys sue Democrat Governor Gretchen Whitmer

12:12 pm

Gretchen Whitmer, Democrat and would-be dictator
Michigan Governor Gretchen Whitmer, Democrat and would-be dictator

Bring a gun to a knife fight: A coalition of five Michigan bowling alleys has sued Democratic Party Governor Gretchen Whitmer as well as the state’s Department of Health and Human Services Director Robert Gordon for shutting down their businesses for more than a year during the Wuhan panic without providing them any just compensation.

You can read the complaint here [pdf].

Plaintiff’s chief counsel David Kallman told The Epoch Times after the appeals court hearing…
“Michigan is the only state in the nation where a governor’s public health emergency powers were overturned as unconstitutional. If we lose in the court of appeals, we will take this case to the U.S. Supreme Court.”

Scott Bennett, executive director of the Independent Bowling and Entertainment Centers Association, told The Epoch Times: “The governor’s actions were devastating to our industry. Things went from ‘two weeks to slow the spread’ to indefinite shutdowns.”
» Read more

19 comments

Perseverance’s upcoming travel plans

10:12 am

Overview map
Click for interactive map.

Today’s update from the Perseverance’s science team provided a rough outline of their travel and drill-sampling plans for the Mars rover in Jezero Crater as it begins its climb up onto the delta that once poured into the crater. The route they plan to travel initially is dubbed Hawksbill Gap.

At Hawksbill Gap, however, we may instead carry out the first portion of the sampling sol path (which includes abrasion and collecting observations using our proximity science instruments) at up to 5 locations along our ascent. After that, we’ll turn around and begin a descent back down Hawksbill Gap and collect rock core samples at 3 of our abrasion locations.

This modified sampling strategy is intended to provide the team with valuable contextual information as we climb Hawksbill Gap and interpret the delta stratigraphy around us. With proximity science data in-hand, we can down-select our sampling sites to ensure we’ll be collecting the most scientifically valuable cores along our descent. Of course, we still maintain the option of collecting sample cores at any point during our ascent, if the team decides a particular abrasion site warrants immediate sampling.

The map above shows my guess (the red dotted lines) as to their potential routes uphill. As the science team has so far not published a map indicating exactly where Hawksbill Gap is, I can only guess at this point. The blue dot indicates Perseverance’s present position, the green dot Ingenuity.

As for the helicopter, there is no word yet whether the engineers have successfully gotten its batteries back to full charge. Until then, it cannot fly, and is also at risk of freezing up in the cold Martian winter.

Leave a comment

India delays launch of manned mission to do two abort tests first

9:37 am

The new colonial movement: India’s space agency ISRO has decided to delay the launch of its Gaganyaan manned orbital mission at least one more year (until ’24) in order to do two abort tests of the capsule.

“The first Test Vehicle for this purpose is ready and we will launch it in September this year. The human capsule will be sent up 15 kilometres, we will simulate an abort and then the capsule will be safely brought down by parachutes into the sea,’’ Somanath, who is also Secretary, Department of Space, said.

The second Test Vehicle will be launched in December this year, sent to a greater height and then brought back after a similar simulation is carried out.

The mission had originally been scheduled to launch in ’22, but was delayed significantly by India’s panic over Wuhan.

Leave a comment

Zhurong goes into hibernation

9:30 am

Overview map

According to a report today in China’s state-run press, the team running its Zhurong Mars rover have placed it into a hibernation mode in order to sit out the Martian winter.

To tackle the dust storms and low-temperature challenges, the Chinese rover went into dormancy on Wednesday. It is expected to wake up and resume work in December when the dust clears and Mars enters its spring season, the administration said in a statement.

The rover sits somewhere in the blue circle in the map to the right, created using elevation data and images from Mars Reconnaissance Orbiter (MRO). This region is about 25 degrees north latitude, so though it is in the dry equatorial regions of Mars, it still gets very cold in winter, down to -180 degrees Fahrenheit at night. Furthermore, the increased winter dust storms block the light from the Sun, which reduces the available power the rover’s solar panels can produce.

Chinese engineers have apparently adapted the hibernation techniques they use on the Moon with their Yutu-2 rover to place Zhurong in hibernation.

Leave a comment

Starliner reaches proper orbit despite thruster problems

9:08 am

Unbelievable: During the post-launch press conference last night Boeing officials revealed that, though the final burn to get Boeing’s Starliner capsule into orbit using its own thrusters succeeded, the thrusters did not function as planned.

Boeing Vice President Mark Nappi said a Starliner thruster failed after firing for one second as the spacecraft made a burn to enter orbit after separating from its Atlas V launch vehicle. The flight software switched to a second thruster, which fired for 25 seconds before shutting down prematurely. A third thruster took over and completed the firing, Nappi said.

The thrusters were made by Aerojet Rocketdyne, which also made the valves that did not work in the previous launch attempt in the summer of 2021. Whether the two problems are related is not known at this time.

A NASA official also noted that a cooling unit on the spacecraft operated “sluggishly during ascent,” but began working correctly once in orbit.

Right now NASA and Boeing are planning to proceed with the docking on ISS tonight at 7:10 pm (Eastern). It appears that though two thrusters have failed, they have ten more thrusters that can be used for further maneuvers throughout the mission. Furthermore, these thrusters are not used during the actual rendezvous and docking.

The live stream of the docking goes live at 3:30 pm (Eastern), and is embedded below. Until then enjoy NASA propaganda, some of it might be of interest.

Update: NASA has cut off coverage of the docking on the channel I had embedded previously. I have now embedded an active live feed.

» Read more

9 comments

ULA’s Atlas-5 rocket successfully launches Starliner into orbit

4:29 pm

Atlas-5 immediately after lift-off
Screen capture just after lift-off

Capitalism in space: ULA’s Atlas-5 rocket today successfully launched Boeing’s manned Starliner capsule into orbit on its second attempt to complete an unmanned demo mission to ISS.

The capsule having been deployed by the rocket then followed with a final burn using the capsule’s own engines to get into its proper orbit for rendezvous with ISS tomorrow at 7:10 pm (Eastern). It was during this rendezvous period that Starliner had its problems in the first demo mission in December 2019 that caused the mission to be aborted prior to docking. Hopefully those software issues have been solved and all will go well through tomorrow.

It is interesting to compare the operation and equipment of Boeing/ULA vs SpaceX. While SpaceX has aimed for a sleek look, Boeing/ULA both retain the industrial feel of past rocketry. Neither is wrong, but the difference highlights the consequences of having competing operations. You get variety.

The leaders in the 2022 launch race:

21 SpaceX
15 China
7 Russia
3 Rocket Lab
3 ULA

American private enterprise now leads China 30 to 15 in the national rankings, and the entire world combined 30 to 25.

10 comments

Pushback: Two Alaska Airlines flight attendants fired for asking questions file lawsuit

1:57 pm

Alaska Airlines: Opposed to free speech and religious freedom
Alaska Airlines: Opposed to free speech and religious freedom
Picture credit: Quintin Soloviev

Bring a gun to a knife fight: Today’s blacklist story is a follow-up on a September 2021 story about two flight attendants — Marli Brown and Lacey Smith — who were fired by Alaska Airlines because they had the nerve to question the airline’s public support of a gay rights bill, and asked those questions on a forum the airline had itself arranged for employees to comment.

At the time the attendants, represented by the First Liberty Institute, had filed a complaint with the Equal Employment Opportunity Commission (EEOC), which recently issued “right-to-sue” letters to both attendants.

First Liberty has now filed its lawsuit, which you can read here [pdf]. The suit is against both Alaska Airlines and the Association of Flight Attendants Association of the AFL-CIO that failed to defend both Brown and Smith. From the complaint:

On February 25, 2021, Alaska Airlines posted an article about its support for the Equality Act to an internal employee message board and solicited employee comments. The Equality Act is proposed legislation that would add “sexual orientation and gender identity” as protected classes to a variety of federal statutes and would curtail the applicability of the Religious Freedom Restoration Act.

In response, Marli and Lacey felt compelled by their Christian faith to post one comment each, asking about the impact of the Equality Act on civil rights for religion and women in the workplace.

Alaska Airlines responded to Marli and Lacey’s posts by immediately removing Marli and Lacey from their flight schedules, terminating their employment, and disparaging their religious expression and beliefs as “discriminatory,” “hateful,” and “offensive.”
» Read more

6 comments

ESA releases new images from Solar Orbiter

10:53 am

The Sun's south pole, as seen by Solar Orbiter at perihelion
The Sun’s south pole, as seen by Solar Orbiter at perihelion. Click for full movie.

The European Space Agency (ESA) yesterday released a few of the images taken by its Solar Orbiter spacecraft before and during its first perihelion (closest point in its orbit) on March 26, 2022.

The spacecraft was inside the orbit of Mercury, at about one-third the distance from the Sun to the Earth, and its heatshield was reaching around 500°C. But it dissipated that heat with its innovative technology to keep the spacecraft safe and functioning.

Solar Orbiter carries ten science instruments – nine are led by ESA Member States and one by NASA – all working together in close collaboration to provide unprecedented insight into how our local star ‘works’. Some are remote-sensing instruments that look at the Sun, while others are in-situ instruments that monitor the conditions around the spacecraft, enabling scientists to ‘join the dots’ from what they see happening at the Sun, to what Solar Orbiter ‘feels’ at its location in the solar wind millions of kilometres away.

The photo above, cropped, reduced, and revised slightly to post here, looks at the Sun’s south pole, from the side. The surface of the Sun (the top two thirds) almost looks like thunderheads on Earth, except the rain coming from them are high energy heat and radiation.

The data produced a lot of fascinating short movies, all available at the link, including a phenomenon the scientists have nicknamed a “space hedgehog” because of its look. About 15,000 miles across, “At present no one knows exactly what it is or how it formed in the Sun’s atmosphere.”

Leave a comment

Watching Boeing’s Starliner launch tonight

10:24 am

At 6:54 pm (Eastern) tonight a ULA Atlas-5 rocket will launch Boeing’s manned Starliner capsule on its second attempt to complete an unmanned demo mission to ISS.

NASA’s live coverage will begin at 6 pm on NASA-TV. I have embedded the youtube channel of this live stream below the fold. At the moment the station is broadcasting its regular NASA propaganda (some of which is actually informative). The launch’s actual coverage will begin at 6 pm (Eastern), and continue until the spacecraft is successfully inserted into orbit. Further coverage of the flight, including docking with ISS, will be as follows:

9 pm (Eastern) – Post launch press conference (time subject to change).

May 20
3:30 pm (Eastern) – Coverage begins of the rendezvous and docking to ISS, with the actual docking scheduled for 7:10 pm (Eastern).

May 21
11:30 am (Eastern) – Coverage of the opening of Starliner’s hatch, scheduled for 11:45 am (Eastern).

Boeing’s first attempt to complete this mission in December 2019 was forced to return to Earth before docking with ISS because of numerous software issues. Then, an attempt to launch again in August 2021 was scrubbed because numerous valves in the capsule’s service module failed to operate properly during the countdown. The company had to return the capsule to the factory to replace that service module as well as make some changes to the valves to make today’s launch possible.

For Boeing, these delays and fixes have cost the company a lot of money, since its contract with NASA is fixed price. This second demo mission will cost Boeing about $400 million, but even worse, the delays meant that SpaceX got some of the business with NASA and other private customers that it might have gotten had Starliner been operational.

Update: NASA has cut off coverage of the docking on the channel I had embedded previously. I have now embedded an active live feed.

» Read more

8 comments

Technical issue on New Shepard delays fifth passenger flight

9:57 am

Capitalism in space: Because of an as yet unexplained technical issue discovered on its New Shepard suborbital spacecraft, Blue Origin has scrubbed tomorrow’s planned fifth passenger flight.

The only information the company released was in a tweet yesterday:

During our final vehicle check-outs, we observed one of New Shepard’s back-up systems was not meeting our expectations for performance.

No other information has so far been released, nor has the company indicated when the flight might be rescheduled. It is intended to carry six passengers on a short suborbital flight, including one making his second flight on New Shepard.

Leave a comment

Puzzling telemetry from Voyager-1 suggests problem

9:49 am

Engineers are puzzling over strange operational data coming from Voyager-1, launched in 1977 and now in interstellar space more than 14 billion miles away, that suggests a technical problem but also makes no sense.

The engineering team with NASA’s Voyager 1 spacecraft is trying to solve a mystery: The interstellar explorer is operating normally, receiving and executing commands from Earth, along with gathering and returning science data. But readouts from the probe’s attitude articulation and control system (AACS) don’t reflect what’s actually happening onboard.

The AACS controls the 45-year-old spacecraft’s orientation. Among other tasks, it keeps Voyager 1’s high-gain antenna pointed precisely at Earth, enabling it to send data home. All signs suggest the AACS is still working, but the telemetry data it’s returning is invalid. For instance, the data may appear to be randomly generated, or does not reflect any possible state the AACS could be in.

The issue hasn’t triggered any onboard fault protection systems, which are designed to put the spacecraft into “safe mode” – a state where only essential operations are carried out, giving engineers time to diagnose an issue. Voyager 1’s signal hasn’t weakened, either, which suggests the high-gain antenna remains in its prescribed orientation with Earth.

Figuring out what has happened is made more difficult by distance. It takes about 20 hours for signals to get from Voyager-1 to Earth, even at the speed of light. Thus, any attempted fix will arrive almost two days after it first occurred, at the soonest.

Both Voyager-1 and Voyager-2 are still operating, though at significantly reduced power. It is expected that sometime in the next few years their nuclear power sources will finally be unable to produce enough power to keep them functioning. If so, both spacecraft will have survived the maximum time predicted when launched.

3 comments

A giant elliptical galaxy

3:14 pm

A giant elliptical galaxy
Click for full image.

Cool image time! The image to the right, reduced to post here, was taken by the Hubble Space Telescope of the giant elliptical galaxy NGC 474.

Located some 100 million light-years from Earth, NGC 474 spans about 250,000 light-years across – that’s 2.5 times larger than our own Milky Way galaxy! Along with its enormous size, NGC 474 has a series of complex layered shells that surround its spherical-shaped core. The cause of these shells is unknown, but astronomers theorize that they may be the aftereffects of the giant galaxy absorbing one or more smaller galaxies. In the same way a pebble creates ripples on a pond when dropped into the water, the absorbed galaxy creates waves that form the shells.

About 10% of elliptical galaxies have shell structures, but unlike the majority of elliptical galaxies, which are associated with galaxy clusters, shelled ellipticals usually lie in relatively empty space. It may be that they’ve cannibalized their neighbors.

NGC 474 is no exception, also located in a relatively empty region of space.

2 comments
1 … 238 239 240 241 242 … 1,100