Starship and SLS

Humanity is on the edge of a spaceflight revolution … maybe.

With the two largest, most powerful rockets humanity has so far created both weeks (or months) away from taking their first flights out of Earth’s atmosphere, space scientists are busily drawing their plans for future deep space missions, according to an April 12, 2022, report from Jonathan O’Callaghan at the venerable popular science magazine Scientific American.

Pointing to the cargo constraints our current fleet of space-going vehicles suffers, O’Callaghan paints a picture of “eager scientists” dreaming up new and exotic missions to destinations that remain unreachable even now as the parallel development of NASA’s Space Launch System (SLS) and SpaceX’s Starship Heavy Lift Vehicle come to near simultaneous completion. Both launch systems will be larger than the Saturn V that first carried humanity to the moon and which remained until now the biggest, most powerful machine to ever fly.

To exemplify that new spirit of hope, SciAm quotes Alan Stern of the Southwest Research Institute in Texas. Stern was head of NASA’s New Horizons mission that reached Pluto in 2015, and he had this to say:

These rockets can enable whole new classes of missions: to all the giant planets and the Kuiper belt objects, to the ocean world satellites and the dwarf planets of the solar system. They’re across-the-board useful.

Huge rockets are the future and the past

The concept of oversize rockets Stern is praising is not new. The big dumb booster (BDB) has been a staple of both pulp science fiction and the fanciful dreams of engineers since the heady early days of the Space Race.

Back in 1962, the folks at Aerojet whipped up plans for the Sea Dragon, a two-stage heavy lift vehicle that would have launched while bobbing like a cork in the ocean. A few years later, the German company OTRAG designed a two-stage BDB that looked very much like the modular design of United Space Alliance’s Delta IV Heavy or SpaceX’s Falcon Heavy. Also like SpaceX, OTRAG focused on mass production for reduced cost.

Cost isn’t really a factor for NASA, as it builds the SLS with a slowness spaceflight enthusiasts find painful to watch. The project is years behind schedule and billions over budget, and only a handful of the rockets will be built during the foreseeable and ever-changing future at NASA.

SpaceX, which until 2018 referred to the Starship as the “Big Falcon Rocket” or BFR, is obviously taking a different approach to development of its BDB.

NASA’s SLS is already booked up

SciAm reports that the most serious would-be future solar system explorers are making their plans to go where no humans (or more likely our robotic probes) have gone before based on access to the SLS and its supposedly more mature space shuttle-based technology. But in the next breath, SciAm tells readers the plans NASA has now for the 10 SLS single-use launch vehicles it plans to build and fly make such pure science missions unlikely to leave Earth via that route. All 10 of those rockets are reserved for the Artemis mission’s return to the moon.

There’s even a smoking-gun quote from Robert Stough, payload utilization manager of the SLS at NASA’s Marshall Space Flight Center, in SciAm’s report:

Given the demands of the Artemis program between now and the late 2020s, it’s going to be very difficult to squeeze a science mission in that time frame.

More risk means more reward with Starship

That means the SLS won’t be freed for scientific missions until the 2030s at the earliest, if it ever is at all. The folks who want to fly formerly impossible missions to places like the Kuiper Belt, the watery moons of Saturn or even beyond our solar system know what’s up regarding the availability of the SLS versus Starship. They are, after all, rocket scientists. SciAm quotes Stern again:

Starship holds the promise of transforming the solar system in a way we can’t really appreciate. It completely changes the game.

The rocket scientists aren’t saying the same about the potential of the SLS, at least not until well into the 2030s or even the 2040s. The SLS, even though the prototype is sitting on the launch pad undergoing final testing right now, still seems like the distant future. Starship, which has already flown low-altitude test flights, and crashed, seems like right now.

Starship also seems like a more practical rocket for an age of financial uncertainties. While SciAm reports SLS will cost $4.1 billion per launch, the reusable nature of Starship has SpaceX CEO Elon Musk hoping its per-launch cost could eventually reach as little as $10 million.

Regardless of which launch system performs what tasks, the excitement is palpable as human hopes to finally make a mass movement beyond Earth. To exemplify the anticipation, SciAm quoted Kirby Runyon of the Johns Hopkins University Applied Physics Laboratory, who is part of a proposed mission to probe the atmosphere of Neptune.

There’s a ton of excitement about what really high-performance rockets will enable. The solar system really opens up in a way that’s never been done before.

Bottom line: SpaceX’s Starship and NASA’s SLS are the two largest, most powerful rockets humanity has created so far. Both will soon take first flights out of Earth’s atmosphere. Some are saying they will herald a “spaceflight revolution.”

The post Will Starship and SLS herald a spaceflight revolution? first appeared on EarthSky.

Neptune is the eighth planet outward from our sun. Far from the sun’s light and heat, it’s a forbiddingly cold world, with an average temperature of -364 degrees Fahrenheit (-220 degrees Celsius). But last week (April 11, 2022), an international team of astronomers said they’d measured a surprising drop in temperature in Neptune’s atmosphere, followed by a dramatic warming at the planet’s south pole. They’re perplexed and said these findings were unexpected.

The researchers used the European Southern Observatory’s Very Large Telescope and several other telescopes, both on Earth and in space, to make their discovery. They published the peer-reviewed results in The Planetary Science Journal on April 11 (open access).

Unexpected variations in Neptune’s temperatures

The variations in temperature were surprising and unexpected, as Michael Roman, lead author at the University of Leicester, U.K., stated:

This change was unexpected. Since we have been observing Neptune during its early southern summer, we expected temperatures to be slowly growing warmer, not colder.

The researchers made the discovery after examining nearly 100 thermal infrared images of Neptune. The images were taken over a 17-year period. They revealed something rather unusual: even though southern summer was beginning on the planet, most of the planet had gradually cooled over the last two decades. Overall, the global average temperature of Neptune dropped by 46 degrees Fahrenheit (8 degrees Celsius) between 2003 and 2018. Why?

Then, during the last two years of observations, the temperatures at Neptune’s south pole dramatically warmed. In fact, they rapidly rose 52 degrees Fahrenheit (11 degrees Celsius) between 2018 and 2020.

Neptune does have a relatively warm polar vortex in its atmosphere over its south pole. However, scientists had never observed this kind of rapid warming until now. As Glenn Orton, a senior research scientist at NASA’s Jet Propulsion Laboratory (JPL), noted:

Our data cover less than half of a Neptune season, so no one was expecting to see large and rapid changes.

Thermal-infrared image analysis

How did the astronomers measure the temperature changes on Neptune? They used thermal cameras that measure the infrared light emitted from astronomical objects. Their study of the images was comprehensive, using all known images taken by ground-based telescopes over the past two decades. In particular, they examined Neptune’s stratosphere.

It was southern summer on Neptune during the observations. The atsronomers were able to build a more comprehensive picture of the temperature variations during this time period. Co-author Leigh Fletcher at the University of Leicester, U.K., said:

This type of study is only possible with sensitive infrared images from large telescopes like the VLT that can observe Neptune clearly, and these have only been available for the past 20 years or so.

Possible explanations for Neptune’s temperatures

Scientists don’t yet know for sure what is causing the unexpected changes in temperature. They’re considering various possibilities, such as stratospheric chemistry, random weather patterns or perhaps the solar cycle of the sun.

Only further observations will help to nail down the cause or causes of the temperature fluctuations. In particular, ESO’s Extremely Large Telescope (ELT) could observe such temperature changes in greater detail, and the newly-launched James Webb Space Telescope will provide unprecedented new maps of the chemistry and temperature in Neptune’s atmosphere. All of these observations will provide valuable clues as to just what is happening in Neptune’s chilly atmophere. There is still much to learn about Neptune, as Roman noted:

I think Neptune is itself very intriguing to many of us because we still know so little about it. This all points toward a more complicated picture of Neptune’s atmosphere and how it changes with time.

Multiple telescopes

VLT played a central role in obtaining the images used in the study, specifically the VLT Imager and Spectrometer for mid-InfraRed (VISIR) instrument. But in addition, several other telescopes contributed to the analysis as well, including NASA’s Spitzer Space Telescope and the Gemini South telescope in Chile. Also, the Subaru Telescope, the W. M. Keck Observatory and the Gemini North telescope, all in located in Hawaii, played a part.

Due to its mirror size and altitude, VLT provided the clearest images of Neptune, comparable with ones from the Hubble Space Telescope.

A cold, distant world

At 2.8 billion miles (4.5 billion km) from the sun, Neptune is, unsurprisingly, an intensely cold place, all the time. Even with variations, the average temperature is still a bone-freezing -364 degrees Fahrenheit (-220 degrees Celsius).

Neptune does have seasons, like Earth. However, each season lasts the equivalent of 40 Earth years. It takes Neptunes 165 Earth years to complete one orbit around the sun. The summer season in Neptune’s southern hemisphere began in 2005.

NASA’s Voyager 2 spacecraft flew past Neptune and its moons on August 25, 1989. It is still the only spacecraft so far to have visited these distant worlds.

Bottom line: Neptune’s temperatures are surprisingly both cooler and warmer than expected, scientists say. Several telescopes from around the world and in space made observations for the new international study.

Source: Subseasonal Variation in Neptune’s Mid-Infrared Emission

Via ESO

The post Neptune’s temperatures run oddly warm and cold first appeared on EarthSky.

April 17: X-flare!

Newcomer sunspot region AR2994 blasted out an X-flare at 3:34 UTC this morning (April 17, 2022). Before the blast, we saw a very active northeast limb (edge) of the sun. There seemed to be action on the sun’s far side, too. And now the sun’s rotation has carried some of that action into view. The old sunspot regions AR2975 and AR2976 – last seen some days back before the sun’s rotation carried them out of view – have merged. The newly arrived sunspots are labeled AR2993 and AR2994. Plus, there is one more sunspot in this region, barely showing. All this is happening on the sun’s northeast limb.

A busy week is anticipated with C- and M-class flares and possibly even more X-flares.Stay tuned!

Fantastic! Check out the Xflare with a nice eruption in SUVI 304 angstrom! Explosive! That should make a nice CME ??? pic.twitter.com/xd8lmnfhqg

— Dr. C. Alex Young (@TheSunToday) April 17, 2022

April 16: Sun activity picking up

The sun was busy with multiple flares – between C- and M-class – on Friday and again so far this morning (April 16, 2022)! Most activity had been on the far side, the side we’re currently not seeing from Earth. You can see a classic “lightbulb” shape in a (non-Earth-directed) CME released from one of the flares on the sun’s limb. See the video in Alex’s tweet, below.

A primary flare source appears to be the old sunspot AR2975. There’s lots of chatter online about this region, and about what it’ll be re-named when it comes fully into view, probably around April 17. The sun rotates approximately once every 27 days. So the same sunspots might come into view on the Earth-facing side again and again. Each time, they get a new label.

YAY! Our new friend making some beautiful music! The first 13 hours, April 15 in SDO 171 /131 combined. Shows us the loops, material, and flare activity ~ 600,000 to 10 million kelvin. Notice the classic lightbulb-shape eruption. HOT!! Next week could be very exciting.??? pic.twitter.com/Vyn8mOZh4x

— Dr. C. Alex Young (@TheSunToday) April 15, 2022

April 14: G2 geomagnetic storm is here

A G2 geomagnetic storm – a moderate storm – is ongoing. The Earth-directed CME from the beautiful filament eruption on April 11, 2022, has arrived. By midday on April 14 (according to clocks in North America), the Kp index – which describes the disturbance to Earth’s magnetic field by the solar wind – reached 5 (mild) and may rise to 6 (moderate). Be on the alert for auroras in the next few days. Latitudes like those in the northern United States might see auroras.

According to NOAA’s Space Weather Scales, during a G2-class storm:

Power systems: High-latitude power systems may experience voltage alarms, long-duration storms may cause transformer damage.
Spacecraft operations: Corrective actions to orientation may be required by ground control; possible changes in drag affect orbit predictions.
Other systems: HF radio propagation can fade at higher latitudes, and aurora has been seen as low as New York and Idaho (typically 55 degrees geomagnetic latitude.).

April 14: The sun over the past week

The sun was largely spotless over the past week but there was still a lot going on – including lots of filaments one of which is getting here probably any moment. Most action was from 6 non-Earth-directed CMEs. A look at the week from SDO, 171, 304, 193, and white light. ??? pic.twitter.com/QaKuEeIz3Z

— Dr. C. Alex Young (@TheSunToday) April 14, 2022

April 12: Yesterday’s S-shaped filament eruption

Yesterday, the old sunspot group AR2987 produced an eruptive C1-class solar flare, and more is known about it now. Observers had thought this region was inactive. Spaceweather.com therefore called it the corpse of an old sunspot. The eruption produced a full-halo CME, and the CME is coming our way. Last night, researchers said it might cause a G1-class geomagnetic storm upon reaching Earth’s vicinity. Since then, their prediction has been updated to G2. They are expecting the CME to arrive by April 14, 2022.

In the photo below, note the “S” shape of the filament as it erupts. Early X-ray solar telescopes, such as Yohkoh, were the first to see this S-shaped eruption on the sun clearly and report it widely, in the 1990s. Solar physicists call this S shape a sigmoid. We expect to see more of this sort of eruption as solar activity picks up. It is a signature of strongly built-up magnetic energy in the corona, usually in active regions, and consequently a sign of strong flaring potential and CME eruptions. A very useful signature for predicting strong eruptions!

Sun activity from April 11: Beautiful filament eruption

The sun’s activity picked up on April 11, 2022, with a beautiful filament eruption that simultaneously sent a CME heading our way. NOAA and NASA CME models are not out yet, but we expect the CME to reach Earth around April 13. We wait for updates throughout the day.

Filaments are long ropes of magnetism and solar material supported in the sun’s corona by magnetic fields tied to the sun. They’re the same thing as those great arcs, or prominences, we sometimes see extending from the limb, or edge, of the sun. They’re called filaments, instead of prominences, when seen centrally on the sun. Filaments may originate days to months before they become unstable and get launched into space. After their launch, they send a coronal mass ejection, or CME, hurtling outward.

The series of tweets below show the filament erupting in four different wavelengths of extreme ultraviolet light captured by the SDO spacecraft. First, we see a global view one wavelength after another; below, a closeup with all four wavelengths at the same time. Finally, using the SOHO/LASCO coronagraph, the CME shows up moving away from the sun towards Earth.

Beautiful filament eruption in 4 SDO wavelengths – coolest to hottest. ~80,000 degrees up to several million. Eruption is in the direction of Earth so maybe it will provide some night lights in the sky for us. Should be around the 13th or so. Waiting for models. ???? pic.twitter.com/tTCNOFxuAa

— Dr. C. Alex Young (@TheSunToday) April 11, 2022

Beautiful filament eruption as seen by SDO in different wavelengths. pic.twitter.com/xB7z8tThtw

— Edward.Vijayakumar (@edwanx) April 11, 2022

Filament eruption launched a nice halo CME towards Earth and is expected to impact on April 13th. pic.twitter.com/Et35oNfoZU

— Edward.Vijayakumar (@edwanx) April 11, 2022

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Recent sun activity and aurora photos from the EarthSky community

Bottom line: Sun activity for the week of April 11, 2022, is relatively low; however, there is some to look for. Sun observers expect the CME from an April 11 eruption on the sun to reach Earth April 14.

Click here for last week’s sun activity

The post Sun activity: Bam! X-flare ! first appeared on EarthSky.

Spacewalk on April 18, 2022

On Monday, April 18, 2022, two Russian cosmonauts will perform the first in a pair of spacewalks from the International Space Station (ISS). The goal is to activate a new robotic arm attached to the Nauka module on ISS. NASA’s live coverage of the event will begin on Monday at 14 UTC (10 a.m. EDT) on NASA TV, and the NASA website and mobile app. The spacewalk itself is scheduled to begin at around 14:25 UTC (10:25 a.m. EDT) and is expected to last about seven hours. Watch here.

A new arm for Nauka

Roscosmos cosmonauts Oleg Artemyev and Denis Matveev – of Expedition 67 – will conduct the spacewalk. They’ll begin by exiting the space-facing Poisk module of the station’s Russian segment. At completion, the pair will have installed and connected a control panel for the European robotic arm, a 37-foot-long extension of the Nauka multipurpose laboratory module. They will also remove protective covers from the arm and install handrails on Nauka which will later be used in future spacewalks.

Look for Artemyev in a spacesuit with red stripes. Matveev will be wearing blue stripes.

This spacewalk will be the fourth in Artemyev’s career and the first for Matveev. Moreover, it will be the fourth spacewalk for the station in 2022 and the 249th spacewalk dedicated to maintenance and upgrades.

The second spacewalk in the series is currently scheduled for April 28.

And that spacewalk won’t be the last, as NASA says there will be future spacewalks to continue outfitting the European robotic arm.

The Exp 67 crew is gearing up for a @Commercial_Crew swap and a pair of Russian spacewalks this month. https://t.co/rF1yZ1pApM

— International Space Station (@Space_Station) April 14, 2022

Bottom line: Watch two Russian cosmonauts spacewalk on April 18, 2022.

Read more from EarthSky: The Nauka module mishap that sent ISS tumbling

Via NASA

The post Spacewalk on April 18: A new robotic arm first appeared on EarthSky.

Watch for a daytime moon

This month’s full moon came on the night of April 16, 2022. By April 17, the moon is in a waning gibbous phase, rising later and later on each successive night. For those at temperate latitudes in the Northern Hemisphere, there’s an especially long time between moonrises on successive evenings around now. The April 17 moon will rise more than an hour after sunset. The April 18 moon will rise roughly two to three hours after sunset.

And of course a later rising time means a later setting time. That’s why the the mornings after a full moon are a good time to catch a nearly full daytime moon over your western horizon after sunrise. Watch for it!

The moon is up in the daytime half of the time. But, because it’s pale against the blue sky, it’s not as noticeable during the day as at night. Still, there are certain windows each month during which the daytime moon is most noticeable.

The third week of April 2022 presents one of those windows. It’s a good time to watch for a daytime moon.

By April 19 and 20 mornings, moon near Antares

By the mornings of April 19 and 20, 2022 (or late evening April 18 and 19), the moon will be near the bright star Antares in the constellation Scorpius the Scorpion. At that time, the moon will be rising a little before midnight at mid-northern latitudes. And it’ll still be up after the sun rises, but appearing thinner in phase and higher in the sky with each new dawn.

From the Southern Hemisphere, the moon and Antares will set at early-to-mid evening. Because of Earth’s motion around the sun, Antares – like all the fixed stars – will rise about four minutes earlier each evening. Meanwhile, because of its own motion around Earth, the moon will be rising later and later each evening and thus moving away from Antares’ location in the sky.

Day by day, in the days ahead, the lighted portion of the waning gibbous moon will shrink. The half-lit last quarter moon will come on April 23, 2022.

Bottom line: You can most easily spot the moon in the morning sky – after sunrise – for a few days after full moon. Beginning around April 17, 2022, you’ll see the waning gibbous moon floating pale and beautiful against a blue sky. Look west after the sun comes up!

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April full moon

When to watch in 2022: Nights of April 15 and 16.
Where to look: Look for the bright round moon in the east in the evening, overhead around midnight, west before sunrise.
Crest of the full moon falls at 18:55 UTC on April 16, 2022. That’s 1:55 p.m. CDT in central North America.
Note: The April 15 and 16 moon is near the star Spica in the constellation Virgo.

All full moons rise in the east at sunset and set in the west at sunrise. They are visible all night. At full moon, the sun, Earth and moon are aligned in space, with the Earth in the middle. The moon’s day side – its fully lighted hemisphere – faces us. That’s why the moon looks full. Note that the moon will look full and round for a day or two around full moon. So starting on April 15 the moon will look full for several days and will rise about an hour later each day.

April’s full moon is the Pink Moon

This is such a beautiful time of year, especially when the full moon rises! April’s full moon has the nickname of the full Pink Moon because of all the blooming flowers and trees, in particular the pink creeping phlox (Phlox subulata). The moment of full moon – when it reaches that point in its orbit directly opposite the sun in sky – is April 16 at 18:55 UTC or 1:55 p.m. CDT. However, “full moon” is considered any time 12 hours before or after that.

Read: Full moon names by month and by season

The full moon of April is also called the Paschal Moon if it occurs before Easter, which happens this year. As a general rule, Easter is pinned on the first Sunday after the full moon that occurs after the vernal equinox. This year the equinox fell on March 20, and the following full moon falls on April 16, which is a Saturday. Therefore, the next Sunday is the very next day, making Easter April 17.

Southern Hemisphere view

For Northern Hemisphere moon watchers, the rising Pink Moon glows brightly to the left of Spica, the brightest star in the constellation Virgo.

For Southern Hemisphere viewers, Spica lies above the moon as it rises.

Spotting Spica

Because the full moon is very bright, you might not spot Spica at first. Try blocking the moon behind a foreground object such as a building. Spica is an important star for learning the night sky because it’s the southern member of the easily recognizable Spring Triangle. This asterism also includes Arcturus, north of Spica, and Denebola, northwest of Spica. Those three stars form an attractive equilateral triangle.

As the American night of April 16 advances, the Pink Moon moves away from Spica and nears Virgo’s boundary with Libra, the next zodiacal constellation to the east. Since the full moon sits on the opposite side of the sky from the sun, when morning twilight begins in the east, the full moon nears the western horizon. It then lies noticeably further from Spica than it did when it rose nearly 12 hours earlier.

Bottom line: At full moon, the moon rises around sunset, climbs highest in the sky around midnight, and sets around sunrise. The April 2022 full moon on April 16 is the Pink Moon. It lies near the star Spica in the constellation Virgo.

The post Full moon falls on April 16 first appeared on EarthSky.

Did you see the fireball last night over Germany?

Last night, April 15, 2022, skywatchers reported a brilliant fireball seen and photographed across west-central Europe at 23:27 CEST (21:27 UTC). So far, there have been 32 reports sent to the International Meteor Organization (IMO) of this event. The event page for this fireball is here. If you witnessed this fireball, the IMO invites you to fill out a fireball report as soon as possible.

At the website, you will find a map showing the locations of each witness across west-central Europe. You can adjust the map to display each witness or a heat map. You might also add or remove observing directions in the witness display. If you use the heat map option, you will notice a short trajectory of this fireball near the town of Saarbrücken, Germany. This trajectory is computer generated using the data provided by each witness. There are also several more impressive photographs taken by the AllSky7 Fireball Network available on the event page.

Preliminary analysis indicates that this was a random fireball and not associated with any known meteor shower. Due to the lack of sound associated with this fireball, it is believed that this object completely disintegrated while still high in the atmosphere and that no meteorites survived all the way to the ground.

Bottom line: A fireball lit up the skies over Germany last night. If you witnessed this fireball the IMO invites you to fill out a fireball report as soon as possible.

The post Fireball over Germany! Did you see it? first appeared on EarthSky.

We know there are some awesome dads out there. But the nominees for best dad must surely include the emperor penguins. These males go to extraordinary extremes for their offspring, enduring the bitter cold of Earth’s coldest continent, Antarctica. If you could visit during winter, you’d find emperor penguin males gathered in colonies near the coast. They’ll be tightly huddled together to stay warm in temperatures that can dip as low as -40 F (-40 C), and strong winds up to 90 miles per hour (144 km/ hour). These devoted penguin dads will each incubate a single egg that holds his offspring and care for his chick when it first hatches. They do all this while surviving only on fat reserves from the previous summer.

It’s autumn in Antarctica now, time for the emperor penguins’ breeding cycle to start.

Childcare division among emperor penguins

EarthSky talked to Emperor penguin expert Barbara Wienecke, who is a seabird ecologist at the Australian Antarctic Division. She said:

Why the males are taking care of the incubation rather than the females is somewhat unclear. Males tend to be slightly larger than females and may be able to store more fat. The females also depend on fat reserves since they fast for a good two months before they lay their egg and then head out again. In quite a few bird species, it’s the male who looks after the kids. In Malleefowl, for example, the only thing a female does is lay the eggs. Her partner does the rest.

Wienecke also told EarthSky:

From an evolutionary point, it makes sense that only one parent incubates the egg. We know from our tracking studies that the females potentially could return to the colony and relieve their mates of their incubation duties. But transferring an egg is a very high risk activity at the best of times, and particularly in winter. If the transfer takes too long, the egg freezes. The older the embryo, the quicker it will die. 

Precious pear-shaped egg

For much of the summer, male and female emperor penguins are at sea, feeding on fish, squid and krill. For the males, this is the time to accumulate the fat reserves they’ll need to survive the next winter.

In April, which is autumn in the Southern Hemisphere, adult emperor penguins begin congregating at their breeding colonies, traveling up to 56 miles (90 km) to reach the pack ice.

Following courtship displays, the birds form pairs and mate. In May and early June, the female lays a single egg. The egg is pear-shaped with a pale greenish-white tint, almost 5 inches long and 3 inches wide (12 by 8 cm). The female penguin passes the egg to her mate, then heads back to sea. She’ll be back in two months to continue her parental duties.

Until then, the males are on their own for winter in Antarctica. Their dense insulating feathers and fat accumulations, however, aren’t enough to keep them alive. During storms, males – as well as females out hunting – huddle close together to conserve heat. They do this by taking turns moving from the edge of the colony, which is colder, to the warmer center.

The egg, meanwhile, is snugly tucked away in dad’s brood pouch, resting on his feet. If all goes well, the chick will hatch in 65 to 75 days. Hatching will likely happen a few days before mom returns. During this time, the chick, weighing just 11 ounces (312 grams) with only a thin layer of down feathers, is completely dependent on dad for warmth and protection. Until mom returns to start feeding the chick, he also provides his offspring with what’s called crop milk, a high fat and protein secretion.

Winter weightloss

Mom returns to the colony, sometime between mid-July and early August, after spending the last two months feeding at sea. She takes over caring for the chick while dad, having eaten nothing but snow for about 120 days, heads to the ocean to start feeding. By now, he has dropped 40% in weight from his summer weight of about 84 pounds (38 kilograms) to around 50 pounds (23 kilograms).

Dad will spend about three to four weeks feeding at sea, then return to his mate. From then on, the pair takes turns caring for their little one, keeping it warm and feeding it regurgitated krill, fish and squid.

Emperor penguins’ daycare system

About 50 days after hatching, the colony’s chicks, now sporting a thick downy coat, assemble together for warmth and protection in what’s called a crèche. That’s an emperor penguin daycare where the chicks wait for their parents to return from the sea to feed them. Wienecke told EarthSky:

Emperor penguins are very gregarious birds and seek each other’s company. Initially when the first few chicks are left to their own devices in the colony, they will seek other adults and stand near them. As the numbers of chicks who are on their own increases, they crèche (it really looks like a kindergarten: lots of youngsters running around the same area) and start forming chick huddles (the cutest sight imaginable!). In the northern colonies, they tend to do that at night or during inclement weather.

In early November, as spring yields to summer in Antarctica, the chicks undergo a two-month moult, replacing their downy chick feathers with juvenile plumage that will enable them to swim.

By December and January, the chicks are nearly as big as their parents. At this point, mom and dad have done their job and will stop feeding the kids. The youngsters will then venture to sea to start foraging on their own. In about three to four years, they will be old enough to start breeding.

Worrying outlook for Emperor penguins

Wienecke explained to EarthSky how the changing world is affecting emperor penguins:

The outlook for emperor penguins is worrying. Some colonies have moved onto ice shelves or even icebergs in years when the fast ice was in poor condition. But that’s not the best solution in the long term. A) there has to be access (the penguins can’t climb up 40-meter high ice cliffs after all), B) the birds are entirely exposed to very strong winds and often encounter crevasses, and C) snow bridges that provide access can collapse and could leave the penguins stranded. However, the ice structures may provide the relative flat surface emperor penguins need. Flat land is exceedingly rare (at least at the moment) so options are pretty limited.

She continued:

Climate change is threatening the main breeding habitat of emperor penguins. These birds are pretty adaptable because to survive in Antarctica is pretty challenging. But sometimes things go wrong. That is the case no matter where you are. But when events that lead to breeding failure occur increasingly frequently, the penguins – long lived as they are –  will not be able to adapt.

Bottom line: Male emperor penguins are some of the best dads in the world. They incubate their eggs for over two months in the frigid Antarctic winter.

Read more about the emperor penguins breeding cycle

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Scientists announced on April 12, 2022, that they’ve created a high-quality image confirming C/2014 UN271 (Bernardinelli-Bernstein), affectionately known as BB, is the largest Oort Cloud comet yet discovered. The new comet’s nucleus, or core, is about 75 miles (120 km) wide, or about twice the size of Comet Hale-Bopp, which put on such a good show for us in 1997. And BB is headed for the inner regions of the solar system now.

The good news is NASA says it’ll come nowhere near Earth. From NASA’s official announcement:

The behemoth comet, C/2014 UN271 (Bernardinelli-Bernstein) is barreling this way at 22,000 miles per hour (35,400 kph), from the edge of the solar system. But not to worry. It will never get closer than 1 billion miles away from the sun, which is slightly farther than the distance of the planet Saturn. And that won’t be until the year 2031.

The team behind the study published their results on April 10, 2022, in the peer-reviewed Astrophysical Journal Letters.

Discovery of the biggest comet yet

University of Pennsylvania astronomers Pedro Bernardinelli and Gary Bernstein discovered the comet. They were reviewing images from 2014 to 2018 from the Dark Energy Survey as part of their computer-aided search for trans-Neptunian objects.

So how big is it?

At the time of the initial discovery, scientists estimated the comet’s icy, dusty core at 62 to 230 miles (100 to 370 km) wide. The new imagery refines the estimate to a range between 66 and 86 miles (105 to 140 km), making it roughly twice the size of Comet Hale-Bopp. Comet Hale-Bopp appeared as a naked-eye object in 1997 and thrilled observers around the world. The previous record holder for the largest comet nucleus was C/2002 VQ94 (LINEAR), which measures about 60 miles (100 km) at its widest.

The new big kid on the cosmic block is far from alone, said David Jewitt, professor of planetary science and astronomy at UCLA and co-author of the study that refined the comet’s measurements. From NASA’s announcement:

This comet is literally the tip of the iceberg for many thousands of comets that are too faint to see in the more distant parts of the solar system. We’ve always suspected this comet had to be big because it is so bright at such a large distance. Now we confirm it is.

The biggest comet yet is getting closer

While the discovery of Comet BB came in 2014, its first appearance on image data was in 2010. At that time, BB was 3 billion miles (4.8 billion km) from Earth, coincidentally about the average distance to Neptune. Now, the object is about a billion miles closer, yet still well out in the outer reaches of the solar system.

Already the core is shedding gas and dust at an impressive rate of about 2,200 pounds (1,000 kg) a second. The authors of the paper described it as:

… an enormous (albeit uncertain) mass-loss rate.

It was that voluminous outpouring of gas and dust coming from a body so distant in the solar system that prompted the research team to try measuring what they suspected was a huge cometary body. Man-To Hui of the Macau University of Science and Technology, Taipa, Macau, led the team. Hui said:

This is an amazing object, given how active it is when it’s still so far from the sun. We guessed the comet might be pretty big, but we needed the best data to confirm this.

Obtaining images of Comet BB

To gather that data, Hui’s team used the Hubble Space Telescope’s Wide Field Camera 3 to take five photos of the comet on January 8, 2022.

In announcing the team’s find, NASA described the process team members used to discern the size of the nucleus against the backdrop of the glare of the comet’s coma and tails:

The comet is currently too far away for its nucleus to be visually resolved by Hubble. Instead, the Hubble data show a bright spike of light at the nucleus’ location. Hui and his team next made a computer model of the surrounding coma and adjusted it to fit the Hubble images. Then, the glow of the coma was subtracted to leave behind the starlike nucleus.

By combining the Hubble data set with radio observations made by the Atacama Large Millimeter/Submillimeter Array (ALMA) in Chile, the team was able to assign upper and lower limits to the size of C/2014 UN271.

The team also found the comet is less reflective than originally thought. According to Jewitt:

It’s big and it’s blacker than coal.

Bottom line: Comet C/2014 UN271, also known as Comet Bernardinelli-Bernstein or BB, is the biggest comet yet, as confirmed by new Hubble images. The comet is about twice the size of Comet Hale-Bopp, or around 75 miles (120 km) wide.

Source: Hubble Space Telescope Detection of the Nucleus of Comet C/2014 UN271 (Bernardinelli–Bernstein)

Via NASA

The post Biggest comet yet headed to inner solar system first appeared on EarthSky.

For the Northern Hemisphere, mid-April to mid-May is Mercury’s best evening apparition of 2022.

When to watch: Mercury will come into view after sunset in mid-April and be gone again by mid-May. Greatest elongation – when Mercury will be farthest from the sunset – is late April.
Where to look: Look in the sunset direction, as the sky is darkening.
Greatest elongation is 8 UTC on April 29, 2022.
Note: As the innermost planet, Mercury is tied to the sun in our sky. It never ventures very far above the horizon after sunset. As soon as the sun disappears below your horizon, the clock starts ticking. Will you see the glowing point of light that is Mercury before it follows the setting sun?

At greatest elongation in April 2022:

– Mercury’s distance from sun on the sky’s dome is 21 degrees.
– Mercury shines at magnitude 0.3
– Through a telescope, Mercury appears 36% illuminated, in a waxing crescent phase, 8 arcseconds across.

For precise sun and Mercury rising times at your location:

Old Farmer’s Almanac (U.S. and Canada)
Timeanddate.com (worldwide).
Stellarium (online planetarium program)

Mercury events in 2022 and 2023

Jul 16, 2022: Superior conjunction (passes behind sun as seen from Earth)
Aug 27, 2022: Greatest elongation (evening)
Sep 23, 2022: Inferior conjunction (races between Earth and sun)
Oct 8, 2022: Greatest elongation (morning)
Nov 8, 2022: Superior conjunction (passes behind sun as seen from Earth)
Dec 21, 2022: Greatest elongation (evening)
Jan 7, 2023: Inferior conjunction (races between Earth and sun)
Jan 30, 2023: Greatest elongation (morning)
Mar 17, 2023: Superior conjunction (passes behind sun from Earth)
Apr 11, 2023: Greatest elongation (evening)

Heliocentric view of Mercury April 2022

A comparison of elongations

Not all of Mercury’s greatest elongations are created equal. Some are greater than others. The farthest from the sun that Mercury can ever appear on the sky’s dome is about 28 degrees. The least distance is around 18 degrees.

Elongations are also better or worse depending on the time of year they occur.

In the autumn for either hemisphere, the ecliptic – or path of the sun, moon and planets – makes a narrow angle to the horizon in the evening. But it makes a steep slant, nearly perpendicular, in the morning. So – in autumn from either hemisphere – morning elongations of Mercury are best. Then Mercury appears higher above the horizon and farther from the glow of the sun. Evening elongations in autumn are harder to see.

In the spring for either hemisphere, the situation reverses. The ecliptic and horizon meet at a sharper angle on spring evenings and a narrower angle on spring mornings. So – in springtime for either hemisphere – evening elongations of Mercury are best. Meanwhile, morning elongations in springtime are harder to see.

Photos from our community

Submit your photo to EarthSky here.

Some resources to enjoy

Read about greatest elongations, superior and inferior conjunctions: Definitions for stargazers

See the moon phase for every day in 2022. EarthSky lunar calendars now available! Going fast!

Bottom line: For the Northern Hemisphere, mid-April to mid-May is Mercury’s best evening apparition of 2022.

The post Mercury after sunset: Start watching mid-April first appeared on EarthSky.