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Frozen planet Pluto surprises observers with its topography – Skywatching – Castanet.net

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Pluto is a small, rocky object, smaller than the Moon, orbiting the Sun in a wildly elliptical path ranging from 30 to 50 times the Earth-Sun distance, taking it from closer than Neptune to far beyond the outermost planet.

It takes about 248 years to complete each trip. During its “year,” the heat and light it receives from the Sun ranges from 0.1% and 0.04% of what we receive on Earth. This means Pluto is cold, with temperatures ranging from -220 C in summer to -240 C in winter.

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Like Earth, Pluto probably started as a lump of molten rock. Because of its small size it cooled relatively quickly and was soon solid all the way through. If there were ever tectonic plate motions, they would have ceased at that point.

From then on the only forces shaping the surface would have been impacts by other orbiting objects. With no weather or plate motions to erase them, by now we would have expected Pluto’s surface to be a pulverized mess of overlapping craters.

If so, since the Solar System contains lots of small bodies covered with craters, why would we bother to send a spacecraft to have a close look at Pluto?

The reason is that Pluto is one of a unique class of objects orbiting the Sun far beyond the outermost known planets.

These are known as Kuiper Belt Objects. They are not planets. They are lumps of frozen raw material left over from the construction of the Solar System. Out there in the deep freeze, they should be pristine. We have extensively examined the planets in the Solar System, however we had never had a close look at Pluto and other objects in the Kuiper Belt. This was the rationale behind the New Horizons Space Mission.

There was one other issue that aroused curiosity. We would expect Pluto to be a dull, grey object, yet many observers reported that Pluto looks pink. This suggested concentrations of organic (carbon-based) compounds are present on the surface. These could be a preserved sample of the mixture of chemicals received by the Earth when it formed, which formed basis for the development of life.

The spacecraft was launched on Jan. 19, 2006, and arrived at Pluto on July 14, 2015. The images it sent back demolished our preconceptions about what that world would be like.

Instead of a dead, icy rockball smothered with impact craters, the images showed a complex, exotic and active world, with terrain resembling what we see in the high Arctic here on Earth.

They showed rocky highlands, cratered, but not heavily, leading down into something resembling a frozen sea. There are large patches of reddish organic chemicals. On the shore are large, angular lumps of ice, similar to the shattered ice we see where ocean ice meets the shore.

The “sea” ice is broken into huge polygonal plates, divided by narrow lanes of whiter ice. In this case the ice is frozen nitrogen. Those plates indicate the frozen nitrogen must have been subject to occasional melting, forming a temporary liquid nitrogen sea.

These images raise big questions. Firstly, even on the highlands there is not a lot of cratering suggesting something has recycled the surface. Secondly, if the “sea ice” is occasionally melted, where is the heat coming from?

With a melting point of -210 C, nitrogen should remain well frozen throughout the Plutonian year. It looks as though Pluto gets an occasional warming for which we have no explanation. The core of that little world should now be cold and solid.

Close encounters with large planets could produce tidal heat, which is what warms Jupiter’s moons Io and Europa, but there seems no indication there has been any such encounter.

Pluto is a puzzle, and puzzles are what make science interesting.

•••

• Mercury and Mars lie very low in the sunrise glow.

• Jupiter and Saturn are visible in the southern sky and Venus may be seen low in the sunset glow.

• The Moon will reach first quarter on the Nov. 11.

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Marine plankton could act as alert in mass extinction event: UVic researcher – Langley Advance Times

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A University of Victoria micropaleontologist found that marine plankton may act as an early alert system before a mass extinction occurs.

With help from collaborators at the University of Bristol and Harvard, Andy Fraass’ newest paper in the Nature journal shows that after an analysis of fossil records showed that plankton community structures change before a mass extinction event.

“One of the major findings of the paper was how communities respond to climate events in the past depends on the previous climate,” Fraass said in a news release. “That means that we need to spend a lot more effort understanding recent communities, prior to industrialization. We need to work out what community structure looked like before human-caused climate change, and what has happened since, to do a better job at predicting what will happen in the future.”

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According to the release, the fossil record is the most complete and extensive archive of biological changes available to science and by applying advanced computational analyses to the archive, researchers were able to detail the global community structure of the oceans dating back millions of years.

A key finding of the study was that during the “early eocene climatic optimum,” a geological era with sustained high global temperatures equivalent to today’s worst case global warming scenarios, marine plankton communities moved to higher latitudes and only the most specialized plankton remained near the equator, suggesting that the tropical temperatures prevented higher amounts of biodiversity.

“Considering that three billion people live in the tropics, the lack of biodiversity at higher temperatures is not great news,” paper co-leader Adam Woodhouse said in the release.

Next, the team plans to apply similar research methods to other marine plankton groups.

Read More: Global study, UVic researcher analyze how mammals responded during pandemic

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Scientists Say They Have Found New Evidence Of An Unknown Planet… – 2oceansvibe News

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In the new work, scientists looked at a set of trans-Neptunian objects, or TNOs, which is the technical term for those objects that sit out at the edge of the solar system, beyond Neptune

The new work looked at those objects that have their movement made unstable because they interact with the orbit of Neptune. That instability meant they were harder to understand, so typically astronomers looking at a possible Planet Nine have avoided using them in their analysis.

Researchers instead looked towards those objects and tried to understand their movements. And, Dr Bogytin claimed, the best explanation is that they result from another, undiscovered planet.

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The team carried out a host of simulations to understand how those objects’ orbits were affected by a variety of things, including the giant planets around them such as Neptune, the “Galactic tide” that comes from the Milky Way, and passing stars.

The best explanation was from the model that included Planet 9, however, Dr Bogytin said. They noted that there were other explanations for the behaviour of those objects – including the suggestion that other planets once influenced their orbit, but have since been removed – but claim that the theory of Planet 9 remains the best explanation.

A better understanding of the existence or not of Planet 9 will come when the Vera C Rubin Observatory is turned on, the authors note. The observatory is currently being built in Chile, and when it is turned on it will be able to scan the sky to understand the behaviour of those distant objects.

Planet Nine is theorised to have a mass about 10 times that of Earth and orbit about 20 times farther from the Sun on average than Neptune. It may take between 10,000 and 20,000 Earth years to make one full orbit around the Sun.

You may be tempted to ask how an entire planet could ‘hide’ in our solar system when we have zooming capabilities such as the new iPhone 15 has, but consider this: If Earth was the size of a marble, the edge of our solar system would be 11 kilometres away. That’s a lot of space to hide a planet.

[source:independent]

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Dragonfly: NASA Just Confirmed The Most Exciting Space Mission Of Your Lifetime – Forbes

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NASA has confirmed that its exciting Dragonfly mission, which will fly a drone-like craft around Saturn’s largest moon, Titan, will cost $3.35 billion and launch in July 2028.

Titan is the only other world in the solar system other than Earth that has weather and liquid on the surface. It has an atmosphere, rain, lakes, oceans, shorelines, valleys, mountain ridges, mesas and dunes—and possibly the building blocks of life itself. It’s been described as both a utopia and as deranged because of its weird chemistry.

Set to reach Titan in 2034, the Dragonfly mission will last for two years once its lander arrives on the surface. During the mission, a rotorcraft will fly to a new location every Titan day (16 Earth days) to take samples of the giant moon’s prebiotic chemistry. Here’s what else it will do:

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  • Search for chemical biosignatures, past or present, from water-based life to that which might use liquid hydrocarbons.
  • Investigate the moon’s active methane cycle.
  • Explore the prebiotic chemistry in the atmosphere and on the surface.

Spectacular Mission

“Dragonfly is a spectacular science mission with broad community interest, and we are excited to take the next steps on this mission,” said Nicky Fox, associate administrator of the Science Mission Directorate at NASA Headquarters in Washington. “Exploring Titan will push the boundaries of what we can do with rotorcraft outside of Earth.”

It comes in the wake of the Mars Helicopter, nicknamed Ingenuity, which flew 72 times between April 2021 and its final flight in January 2023 despite only being expected to make up to five experimental test flights over 30 days. It just made its final downlink of data this week.

Dense Atmosphere

However, Titan is a completely different environment to Mars. Titan has a dense atmosphere on Titan, which will make buoyancy simple. Gravity on Titan is just 14% of the Earth’s. It sees just 1% of the sunlight received by Earth.

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The atmosphere is 98% nitrogen and 2% methane. Its seas and lakes are not water but liquid ethane and methane. The latter is gas in Titan’s atmosphere, but on its surface, it exists as a liquid in rain, snow, lakes, and ice on its surface.

COVID-Affected

Dragonfly was a victim of the pandemic. Slated to cost $1 billion when it was selected in 2019, it was meant to launch in 2026 and arrive in 2034 after an eight-year cruise phase. However, after delays due to COVID, NASA decided to compensate for the inevitable delayed launch by funding a heavy-lift launch vehicle to massively shorten the mission’s cruise phase.

The end result is that Dragonfly will take off two years later but arrive on schedule.

Previous Visit

Dragonfly won’t be the first time a robotic probe has visited Titan. As part of NASA’s landmark Cassini mission to Saturn between 2004 and 2017, a small probe called Huygens was despatched into Titan’s clouds on January 14, 2005. The resulting timelapse movie of its 2.5 hours descent—which heralded humanity’s first-ever (and only) views of Titan’s surface—is a must-see for space fans. It landed in an area of rounded blocks of ice, but on the way down, it saw ancient dry shorelines reminiscent of Earth as well as rivers of methane.

The announcement by NASA makes July 2028 a month worth circling for space fans, with a long-duration total solar eclipse set for July 22, 2028, in Australia and New Zealand.

Wishing you clear skies and wide eyes.

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