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Look up tonight! The Lyrid meteor shower is reaching its peak! – The Weather Network

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The first meteor shower of Spring, the April Lyrids, are definitely a sight to see.

Timed perfectly on the night of April 21-22, so that the peak of the shower happens the night before the New Moon, there will be no competing sources of light in the sky.

The radiant of the Lyrid meteor shower, at midnight on the night of April 21-22. Credit: Stellarium/Scott Sutherland

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The ‘radiant’ of this meteor shower – the point in the sky where the meteors appear to originate – rises in the east as the Sun sets on April 21, and it tracks across the night sky towards dawn.

The absolute ideal time to watch is in the hours after midnight, when the sky is reaching its darkest, and the radiant is high up in the sky. If your sky is reasonably free of clouds, be sure to get away from city light pollution to get the best view!

Lyrid-2020-NATCloudCover

Lyrid meteors originate from a stream of dusty, icy meteoroid debris left behind by Comet C/1861 G1 Thatcher. The comet itself is currently billions of kilometres away, out beyond the orbit of Pluto, and will not be seen again until the year 2276. Still, each year we receive a reminder of its existence, as Earth passes through the near constant stream of tiny meteoroids strung out along the comet’s path. Each year in April, this shows up as streaks of light across the sky, peaking around April 22.

Comet-Thatcher-Path-NASA-CNEOSThis plot shows the path of Comet Thatcher through the solar system. Now, on April 21-22, Earth is intersecting with that path. As the inset shows, at this time, the comet itself is over 16 billion kilometres away, out beyond the orbit of Pluto. Credit: NASA CNEOS/Scott Sutherland

Related: Want to find a meteorite? Expert Geoff Notkin tells us how!

METEOR? METEOROID? METEORITE?

These bright streaks are known as ‘meteors’, and they occur as the meteoroids are swept up and plunge through Earth’s upper atmosphere. Travelling at around 100,000 km/h, a meteoroid compresses the air in its path until that air glows white-hot. A meteor flash typically lasts but a second (or less), but the larger a meteoroid is, the brighter and longer-lived its meteor will be. This is how we get fireballs, and even explosive ‘bolides’ for the largest meteoroids. The meteor winks out either when the meteorid is vapourized, or when the ‘push-back’ from the atmosphere slows the meteoroid down to the point where it can’t compress the air any more.

The stream of meteoroids from Comet Thatcher tends to be relatively sparse. Thus, even at the meteor shower’s peak, the Lyrids only deliver around 20 meteors per hour. Most viewers only see about half that number.

Embedded within the stream, however, are some larger meteoroids, and when those hit the atmosphere, bright fireballs add to the show!

Some fireballs and bolides can actually leave behind bits of the meteoroid that fall to Earth. When these are found on the ground, they are called meteorites.

Related: Got your hands on a space rock? Here’s how to know for sure

COMET & ASTEROID SCARES

In recent weeks, there has been a lot of overblown doomsday hype about possible threats from asteroids and comets.

To state this clearly: There are no threats to Earth from asteroids or comets, and any stories saying differently are wrong, or are outright misinformation. Also, this meteor shower has nothing to do with any threat to Earth. There are multiple meteor showers each year, and they are events to be enjoyed, rather than omens to be feared.

One particular target for this doomsday nonsense is asteroid 52768 (1998 OR2), which is passing by Earth on April 29, 2020.

Asteroid-52768(1998 OR2)-flyby-April292020The orbit of 52768 (1998 OR2), as of April 29, 2020. The inset view shows the asteroid safely positioned far beyond the orbit of the Moon during its closest pass. Credit: NASA CNEOS/Scott Sutherland

These stories have originated from various ‘tabloid’ news sources around the world. With flashy headlines proclaiming “NASA Warns” and using phrases like “Approaching Earth”, they heavily imply that the space agency is issuing alerts about impending impacts with Earth.

Nothing could be farther from the truth, however.

Asteroid 52768 (1998 OR2) was discovered in 1998, and astronomers have logged over 3,500 observations of it, some going back as far as 1987. With that much information at their fingertips, scientists have locked down the orbit of this object.

The main reason these stories seem to be hyping this fly, apparently, is due to the asteroid’s size. 52768 (1998 OR2) is estimated at being around 2.5 kilometres wide. Admittedly, that is significant, and it would be very dangerous if anything like that struck the planet.

As it passes Earth on April 29, however, 52768 (1998 OR2) will be very far away – over 6.3 million kilometres at its closest distance. For reference, that is 16.4 times farther away than the Moon.

Watch below: NASA scientist Kelly Fast, with the Planetary Defense Coordination Office, shows us exactly why there’s no worry about this asteroid!

We now know, with 100 per cent certainty, that 52768 (1998 OR2) is no threat to Earth, either now or at any time in the future.

In fact, the asteroid does not even appear on NASA’s list of ‘potentially hazardous asteroids’ that have any chance of striking us. Some asteroids have earned a place on that list even for having an impact chance that ranks as one chance in ten billion, for a date over 100 years from now. 52768 (1998 OR2) is not on that list now, nor has it ever been (some asteroids live on the list for awhile, and then are removed when further observations demonstrate it is no threat).

Remarkably, the Arecibo Radio Observatory team, operating out of Puerto Rico, captured radar images of 52768 (1998 OR2) over the weekend, by bouncing radio waves off the asteroid’s surface.

Now, as always, NASA states that there are no known asteroid threats for the next 100 years (or more).

Sources: NASA CNEOS | Space Weather | NASA CNEOS | With files from The Weather Network

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SpaceX launch marks 300th successful booster landing – Phys.org

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Credit: Unsplash/CC0 Public Domain

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.

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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 .

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 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)
retrieved 24 April 2024
from https://phys.org/news/2024-04-spacex-300th-successful-booster.html

This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no
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Wildlife Wednesday: loons are suffering as water clarity diminishes – Canadian Geographic

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The common loon, that icon of northern wilderness, is under threat from climate change due to declining water clarity. Published earlier this month in the journal Ecology, a study conducted by biologists from Chapman University and Rensselaer Polytechnic Institute in the U.S. has demonstrated the first clear evidence of an effect of climate change on this species whose distinct call is so tied to the soundscape of Canada’s lakes and wetlands.

Through the course of their research, the scientists found that July rainfall results in reduced July water clarify in loon territories in Northern Wisconsin. In turn, this makes it difficult for adult loons to find and capture their prey — mainly small fish — underwater, meaning they are unable to meet their chicks’ metabolic needs. Undernourished, the chicks face higher mortality rates. The consistent foraging techniques used by loons across their range means this impact is likely echoed wherever they are found — from Alaska to Canada to Iceland.

The researchers used Landsat imagery to find that there has been a 25-year consistent decline in water clarity, and during this period, body weights of adult loon and chicks alike have also declined. With July being the month of most rapid growth in young loons, the study also pinpointed water clarity in July as being the greatest predictor of loon body weight. 

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One explanation for why heavier rainfall leads to reduced water clarity is the rain might carry dissolved organic matter into lakes from adjacent streams and shoreline areas. Lawn fertilizers, pet waste and septic system leaks may also be to blame.

The researchers, led by Chapman University professor Walter Piper, hope to use these insights to further conservation efforts for this bird Piper describes as both “so beloved and so poorly understood.”

Return of the king

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Giant prehistoric salmon had tusk-like teeth for defence, building nests

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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.

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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.

Brenna Owen, The Canadian Press

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