Science
What Is A Super-Earth? – Worldatlas.com
Our solar system is home to three different types of planet: terrestrial, gas giant, and ice giant. However, these do not represent every type of planet. In fact, our solar system is unique in that it does not contain one of the most common types of planets in our galaxy: super-Earths. As their name suggests, super-Earths are rocky worlds whose mass exceeds that of the Earth. More specifically, super-Earths are planets that have a mass between 1.5 to 10 Earths.
Discovery
The first super-Earth ever discovered was also the first planet found beyond our solar system. In 1992, a team of astronomers detected two planets orbiting a distant pulsar. Analysis of their masses showed that both were approximately four times the mass of Earth, making them too small to be gas giants. However, since they are in orbit around a pulsar, they are not defined as true exoplanets since an exoplanet is defined as a planet that orbits a main sequence star. The first super-Earth discovered around a main sequence star was Gliese 876d in 2005. Two years after the discovery of Gliese 876d, astronomers confirmed the existence of a super-Earth located in the habitable zone of the red dwarf star called Gliese 581.
In 2009, NASA launched the Kepler Space Telescope. The primary objective of Kepler was to look for and study exoplanets. To find exoplanets, Kepler looks for any changes to a star’s brightness that may be caused by a planet passing in front of the star. Kepler remained in operation until 2018, and in the nine years it was operational, it fundamentally changed the science of exoplanets. Over its lifetime, Kepler confirmed the existence of over 2,000 individual planets. Just two years into its mission, Kepler data revealed the existence of nearly 300 super-Earths, including Kepler’s first super-Earth found in the habitable zone. Called Kepler-22b, it has a size 2.5 times greater than Earth and orbits a star similar to our sun.
Abundance of Super-Earths
Super-Earths have turned out to be one of the most common types of planet in our galaxy. Data from NASA shows that there are a total of 1,582 confirmed super-Earths around other stars. There are a total of 5,157 exoplanets confirmed as of September 1, 2022, and so super-Earths make up just over 30% of confirmed exoplanets. Furthermore, most rocky planets found in the habitable zones of other stars are also super-Earths.
Habitability of Super-Earths
Since super-Earths make up the bulk of potentially habitable planets, it makes sense to wonder if planets larger than Earth could still be habitable. The potential habitability of a super-Earth will be dependent upon how massive it is. For example, super-Earths that exceed 2-3 Earth masses may hold onto extremely dense, hydrogen rich atmospheres, or they may experience a runaway greenhouse effect similar to Venus. However, some research suggests that super-Earths around twice the mass of Earth could potentially develop conditions that are more suited to life than those on Earth are. A planet more massive than Earth will have a flatter topography due to the high surface gravity, and any oceans will be significantly larger and more shallow than those on Earth. This could potentially create massive chains of archipelago islands, which on Earth tend to house some of the highest amounts of biodiversity. A super-Earth could also retain more internal heat and maintain geologic processes for longer periods of time.
Brenna Owen, The Canadian Press
Published Wednesday, April 24, 2024 7:27PM EDT
Last Updated Wednesday, April 24, 2024 7:27PM EDT
The artwork and publicity materials showcasing a giant salmon that lived five million years ago were ready to go to promote a new exhibit, when the discovery of two fossilized skulls immediately changed what researchers knew about the fish.
Initial fossil discoveries of the 2.7-metre-long salmon in Oregon in the 1970s were incomplete and had led researchers to mistakenly suggest the fish had fang-like teeth.
It was dubbed the “sabre-toothed salmon” and became a kind of mascot for the Museum of Natural and Cultural History at the University of Oregon, says researcher Edward Davis.
But then came discovery of two skulls in 2014.
Davis, a member of the team that found the skulls, says it wasn’t until they got back to the lab that he realized the significance of the discovery that has led to the renaming of the fish in a new, peer-reviewed study.
“There were these two skulls staring at me with sideways teeth,” says Davis, an associate professor in the department of earth sciences at the university.
In that position, the tusk-like teeth could not have been used for biting, he says.
“That was definitely a surprising moment,” says Davis, who serves as director of the Condon Fossil Collection at the university’s Museum of Natural and Cultural History.
“I realized that all of the artwork and all of the publicity materials and bumper stickers and buttons and T-shirts we had just made two months prior, for the new exhibit, were all out of date,” he says with a laugh.
Davis is co-author of the new study in the journal PLOS One, which renames the giant fish the “spike-toothed salmon.”
It says the salmon used the tusk-like spikes for building nests to spawn, and as defence mechanisms against predators and other salmon.
The salmon lived about five million years ago at a time when Earth was transitioning from warmer to relatively cooler conditions, Davis says.
It’s hard to know exactly why the relatives of today’s sockeye went extinct, but Davis says the cooler conditions would have affected the productivity of the Pacific Ocean and the amount of rain feeding rivers that served as their spawning areas.
Another co-author, Brian Sidlauskas, says a fish the size of the spike-toothed salmon must have been targeted by predators such as killer whales or sharks.
“I like to think … it’s almost like a sledgehammer, these salmon swinging their head back and forth in order to fend off things that might want to feast on them,” he says.
Sidlauskas says analysis by the lead author of the paper, Kerin Claeson, found both male and female salmon had the “multi-functional” spike-tooth feature.
“That’s part of our reason for hypothesizing that this tooth is multi-functional … It could easily be for digging out nests,” he says.
“Think about how big the (nest) would have to be for an animal of this size, and then carving it out in what’s probably pretty shallow water; and so having an extra digging tool attached to your head could be really useful.”
Sidlauskas says the giant salmon help researchers understand the boundaries of what’s possible with the evolution of salmon, but they also capture the human imagination and a sense of wonder about what’s possible on Earth.
“I think it helps us value a little more what we do still have, or I hope that it does. That animal is no longer with us, but it is a product of the same biosphere that sustains us.”
This report by The Canadian Press was first published April 24, 2024.
Science
Nasa's Hubble marks 34th anniversary with stunning view of Little Dumbbell Nebula – The Times of India
In celebration of its 34th anniversary, Nasa‘s Hubble Space Telescope has once again wowed astronomers and space enthusiasts alike by capturing an extraordinary image of the Little Dumbbell Nebula. This latest image offers a vivid glimpse into the complexities of a planetary nebula, demonstrating Hubble’s enduring capabilities in its extended mission.
The Little Dumbbell Nebula, also known as Messier 76, is one of the faintest objects in the Messier catalog and has intrigued astronomers for its intricate structure and dual-lobed shape. This planetary nebula, located approximately 2,500 light-years away in the constellation Perseus, represents a brief stage in the life cycle of a moderate-sized star like our sun.
Dr. Jennifer Wiseman, a senior scientist at Nasa’s Goddard Space Flight Center, expressed her admiration for the new imagery: “This beautiful nebula is what remains after a star like our own sun has exhausted the bulk of its nuclear fuel and shed its outer layers. The vibrant colors and intricate structures visible in the nebula are a telescope’s way of painting the portrait of the final stages of stellar evolution.”
The Little Dumbbell Nebula, despite its faintness, shines brightly in the detailed images provided by Hubble, allowing scientists to study aspects of the nebula that are rarely visible. The images highlight the dense, glowing gas and complex layers of material expelled from the dying star at the center of the nebula.
According to Dr. Wiseman, “Hubble’s high-resolution capabilities allow us to examine the fine details within the nebula, helping us understand how stars expel their material and the dynamics of this expulsion process. This image is more than just a picture; it’s a deep dive into the life of stars.”
Since its launch on April 24, 1990, Hubble has revolutionized our understanding of the universe, from the dynamics of galaxies to the atmospheres of exoplanets and the distribution of dark matter. Its contributions continue to support and complement data gathered by newer space observatories.
As Hubble continues its journey in space, the scientific community remains enthusiastic about the ongoing contributions it will bring to our understanding of the cosmos. Dr. Wiseman remarked, “Every image from Hubble is a new lesson in our cosmic curriculum.”
These observations not only contribute significantly to our knowledge of the life cycle of stars but also continue to highlight the critical role of Hubble in the exploration and understanding of our universe. As Hubble enters another year in orbit, its legacy of discoveries promises to keep inspiring both the scientific community and the public.
SpaceX sent up the 30th launch from the Space Coast for the year on the evening of April 23, a mission that also featured the company’s 300th successful booster recovery.
A Falcon 9 rocket carrying 23 of SpaceX’s Starlink internet satellites blasted off at 6:17 p.m. Eastern time from Cape Canaveral Space Force Station’s Space Launch Complex 40.
The first-stage booster set a milestone of the 300th time a Falcon 9 or Falcon Heavy booster made a successful recovery landing, and the 270th time SpaceX has reflown a booster.
This particular booster made its ninth trip to space, a resume that includes one human spaceflight, Crew-6. It made its latest recovery landing downrange on the droneship Just Read the Instructions in the Atlantic Ocean.
The company’s first successful booster recovery came in December 2015, and it has not had a failed booster landing since February 2021.
The current record holder for flights flew 11 days ago making its 20th trip off the launch pad.
SpaceX has been responsible for all but two of the launches this year from either Kennedy Space Center or Cape Canaveral with United Launch Alliance having launched the other two.
SpaceX could knock out more launches before the end of the month, putting the Space Coast on pace to hit more than 90 by the end of the year, but the rate of launches by SpaceX is also set to pick up for the remainder of the year with some turnaround times at the Cape’s SLC-40 coming in less than three days.
That could amp up frequency so the Space Coast could surpass 100 launches before the end of the year, with the majority coming from SpaceX. It hosted 72 launches in 2023.
More launches from ULA are on tap as well, though, including the May 6 launch atop an Atlas V rocket of the Boeing CST-100 Starliner with a pair of NASA astronauts to the International Space Station.
ULA is also preparing for the second launch ever of its new Vulcan Centaur rocket, which recently received its second Blue Origin BE-4 engine and is just waiting on the payload, Sierra Space’s Dream Chaser spacecraft, to make its way to the Space Coast.
Blue Origin has its own rocket it wants to launch this year as well, with New Glenn making its debut as early as September, according to SLD 45’s range manifest.
2024 Orlando Sentinel. Distributed by Tribune Content Agency, LLC.
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SpaceX launch marks 300th successful booster landing (2024, April 24)
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Plot twist: Kings steal home ice from Edmonton Oilers in OT stunner – Edmonton Journal
Giant prehistoric salmon had tusk-like teeth for defence, building nests: study – CP24
Developer Sam Mizrahi files lawsuit against Edward Rogers and his real estate fund, alleges $30-million loss – The Globe and Mail
Silver investment demand jumped 12% in 2019
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