Connect with us

Science

10 Things You Might Not Know About The Northern Lights

Published

 on

 

Among Mother Nature’s most breathtaking spectacles, the northern lights are breathtaking. And the northern winter is a great time to witness this spectacular light display. However, the Northern Lights are more complex than they appear at first glance. It’s the result of particles of gas colliding in Earth’s atmosphere in addition to solar ionization and charged solar particles that produce the dancing greens and pinks of the aurora. There are many places to see the Northern Lights, and viewing them is worthwhile.


Gas molecules produce different colors when they collide; like oxygen, produces greens and nitrogen pinks. Here’s a list of 10 things we might not know about the Northern Lights.

Genius Dog 336 x 280 - Animated



10/10 Charged Sun Particles Travel Millions Of Miles Reaching Earth To Create The Phenomenon

When the corona is heated, charged particles escape the sun’s gravitational attraction. Solar particles “blow,” creating solar wind. The particles travel 150 million kilometers at 800 km/s before reaching Earth. Solar wind collisions can cause aurora borealis and other phenomena. Sun plasma eruptions are rare. These explosions are called CMEs or solar storms. If solar storms reach Earth, their radiation is deflected by Earth’s magnetic shield and dumped at the poles. The phenomenon causes the natural beauty humans get to behold.

RELATED: Winter Is Coming: Stay In An Igloo Under The Northern Lights

9/10 The Northern Lights Hues Are Affected By Gas And Distance

The electrons from space collide with gas particles in Earth’s atmosphere, producing the rainbow of colors we see. Different collisions occur above the ionosphere and produce different colors; it’s all about the gas and the altitude. Below 97 kilometers (60 miles) above the ground, oxygen produces green lights, whereas above that, it produces red lights (322 km). Particles of nitrogen gas lead to colored lights of blue or purple-red. Although it is unusual, a contrasting orange and white hue has been spotted on occasion.

8/10 The Northern Aurora Borealis And Southern Aurora Australis Occur Simultaneously And In The Same Shape

Solar storms generate vivid lights across the board, across the Northern and Southern Hemispheres, as they reflect off of the Earth’s magnetic fields and strike the poles. Plus, they’re complete opposites of one another. Seriously, could it get much better than that?! Even though the aurora australis is most visible in Antarctica, it may be viewed from the southern beaches of Argentina, Chile, Australia, and New Zealand. More specifically, 2017 was the first time that New Zealand offered commercial flights that passed through the Southern Hemisphere’s aurora borealis.

7/10 ISS Astronauts Sometimes Fly Through The Northern Lights

Strictly speaking, very few people have witnessed the Northern Lights physically, and even fewer people have flown straight into the aurora borealis! However, several astronauts have done so! About 248 miles above the surface of the Earth is where the International Space Station now resides. Because the Aurora Borealis may appear anywhere from 97 to 1000 kilometers above the surface of the Earth, it is a happy accident that astronauts are occasionally treated to a breathtaking display.

RELATED: Unlock The Colors Of The Arctic On This Northern Lights Tour

6/10 The Northern Lights Are Not Unique To Earth

Contrary to popular belief, Earth isn’t alone in the solar system. And it stands to reason that the same occurrence, Forces from the Sun repelled by the magnetic shields to produce magnificent colored lights, also occurs on other planets. Although all have strong magnetic fields, their colors may differ from Earth’s because of the varied types of gas they contain. In addition, many of these planets have numerous moons that are much bigger than Earth’s, and these moons can alter the spectrum of light reaching the surface.

5/10 The Northern Lights Are So Faint That Cameras Can “See” Them Better Than People Can

Why don’t people discover how many things exist in the cosmos that our eyes can’t detect? Humans are fortunate to have access to amazing technologies such as cameras, which are much more powerful than the eye’s lens and able to identify colors thus that our naked eyes would miss. Amazing photos wouldn’t be possible without some expert photographic work, though. People who want stunning photos of the northern lights need to hire a guide to assist them in finding them and going to the best viewing spots.

Native Arctic residents, including the Inuit and others, have a rich oral tradition, and it is through this tradition that many myths and stories about the northern lights have been transmitted. When the northern lights appear, it is a game that the dead continue to enjoy after they have passed on. What about the ball? The skull of a walrus. The wording in certain variants varies a bit more sinister, and they have an amusing case of walruses messing around with a human skull instead of the other way around.

RELATED: 10 Places To See The Northern Lights In Iceland

3/10 In The Early 17th Century, GALILEO Used The Term “Aurora Borealis” To Describe The Northern Lights

Ancient Greek and Roman terminology seem like the most likely candidates for the origin of the English phrase “aurora borealis.” After all, the names of the planets are derived from mythological deities. Galileo is credited with first using the name “aurora” in the 17th century, naming it after the goddess of the rising sun. Similarly, the word “north wind” in Greek is referred to as “Boreas.” Even though Galileo was not entirely sure exactly what those Northern Lights were, the moniker survived even after more than 400 years.

2/10 Aside From Being A Sight To Behold, The Northern Lights Are Also Known For The Sounds They Make

It’s so bizarre; it could only come from a sci-fi movie! Several individuals have reported hearing what sounds like radio static or hissing when gazing at the lights. Without a doubt, solar-charged particles are responsible for it in some way. An inversion layer is a layer pertaining to the atmosphere in which the temperature rises rather than falls with increasing altitude. It is this layer that effectively traps a discharge of negative electricity. The cracking and crackling sounds that may be witnessed in conjunction with the Aurora Borealis are caused by the discharge of negative electrical charge from the inversion layer during a severe solar storm.

1/10 The Best Place To See Them In North America Is In Places Like Churchill

The name “northern lights” is not chosen at random. In truth, the finest area in North America to watch the aurora borealis is up north. Churchill, Manitoba. Location is a key factor. The auroral oval, a vast ring around Earth’s geomagnetic North Pole where the northern lights are best seen, passes straight above Churchill. Also, a trip to Churchill from Winnipeg takes just two hours, so one might only need to make one stop en route to the North Pole to witness the Aurora Borealis. Tundra Buggies and the Thanadelthur Lounge provide excellent vantage points to view the Aurora Borealis. Many Hotels also offer views of the Northern Lights.

Source link

Continue Reading

Science

UBC Okanagan study to investigate where Eurasian watermilfoil occurs in lakes – Vernon Morning Star

Published

 on


A UBC Okanagan pilot project is seeking to better pinpoint and map where the beginnings of Eurasian watermilfoil (EWM) infestation occurs in the large lakes within the Okanagan Valley watershed.

If this pilot project proves successful, it could become a blueprint for other jurisdictions to follow in their own battles with this aquatic plant or other invasive aquatic species, says UBCO assistant professor Mathieu Bourbonnais.

Bourbonnais, with the Irving K. Barber Faculty of Science, is overseeing the project with the assistance of masters graduate student Mackenzie Clarke.

The data modelling prototype is using the technology of topobathymetric lidar, the science of simultaneously measuring and recording three distinct surfaces – land, water and submerged land up to 20 metres below the water surface – using airborne laser-based infrared imagery sensors.

Bourbonnais says being able to better identify potential or small milfoil patches will give better control management tools for the Okanagan Basin Water Board’s Euroasian watermilfoil harvest program, which currently is about an $800,000 a year initiative to try and control the growth and limit the damage of the invasive water plant.

It could also potentially target specific watermilfoil growth sites before they grow out of control near valley lake areas deemed sensitive by Environment Canada for the preservation of the Rocky Mountain Ridge Mussels.

He said EWM has been a formidable invasive aquatic plant species to control since it was introduced into the Okanagan Valley lake system some 40 years ago.

It has also illustrated to the water board the need to be stringent when trying to avoid the Zebra and Quagga mussels from being introduced into the lake system.

Like watermilfoil, there is no solution for removing the mussels once they are introduced into a lake system. It is a rooted submerged plant inhabiting the shallows waters of lakes across North America.

EWM originated from Asia, Europe and Northern Africa and has spread rapidly, introduced in North America from the ballast water of ships or aquarium activities.

Bourbonnais said a lake choked with watermilfoil growth impacts the biodiversity and food webs reliant on the lake habitat, alter the water temperature and impacts its recreational use for swimmers and boaters.

“The impact of invasive species on our lake aquatic systems costs billions of dollars to deal with across the country. It definitely has an impact both ecologically and economically,” he said.

The pilot project fieldwork will be done by early spring, he said, with the hope it provides data upon which to target areas for harvesting leading up to the permit application process next year.

“The goal is the Okanagan Basin Water Board can take the data generated from this research model and liaise with the province and federal government on how to go forward,” he said.

“We hope it can help the management strategy of where to send the lake rototillers to pull up the plants.”

READ MORE: Milfoil infestation continues to plague Okanagan watershed

OkanaganUBC

Adblock test (Why?)



Source link

Continue Reading

Science

How Do Stars Get Kicked Out of Globular Clusters? – Universe Today

Published

 on


Globular clusters are densely-packed collections of stars bound together gravitationally in roughly-shaped spheres. They contain hundreds of thousands of stars. Some might contain millions of stars.

Sometimes globular clusters (GCs) kick stars out of their gravitational group. How does that work?

Genius Dog 336 x 280 - Animated

There are a few things that can cause GCs to eject stars. Gravitational scattering, supernovae, tidal disruption events, and physical collisions could all be responsible. Whatever’s behind it, the gradual ejection of stars from GCs is an established phenomenon.

The evidence for stellar ejection from GCs is in the tidal tails that stream out from them.

Palomar 5 is a globular cluster being torn apart by the Milky Way. Palomar 5 is the white blob at the center, and the orange is streams of stars. The yellow line with arrows represents the cluster's orbit around the Milky Way. Image Credit: Odenkirchen, Grebel, et al. 2002/Sloan Digital Sky Survey
Palomar 5 is a globular cluster being torn apart by the Milky Way. Palomar 5 is the white blob at the center, and the orange is streams of stars. The yellow line with arrows represents the cluster’s orbit around the Milky Way. Image Credit: Odenkirchen, Grebel, et al. 2002/Sloan Digital Sky Survey

A new study based on data from the ESA’s Gaia mission aims to understand how GCs eject stars. Its title is “Stellar Escape from Globular Clusters I: Escape Mechanisms and Properties at Ejection.” It’s been submitted to the Astrophysical Journal, and the lead author is Newlin Weatherford, an astronomy Ph.D. student at Northwestern University in Illinois.

“Recent exquisite kinematic data from the Gaia space telescope has revealed numerous stellar streams in the Milky Way (MW) and traced the origin of many to specific MWGCs, highlighting the need for further examination of stellar escape from these clusters,” the authors write. This study is the first of a series, and the authors examine all the escape mechanisms and how each one contributes to GC star loss.

GCs are some of the oldest stellar associations in the Milky Way. Individual GC stars are also older and have lower metallicity than the Milky Way’s general population. Nearly all galaxies host GCs, and in spiral galaxies like ours, the GCs are mostly found in the halo. The Milky way hosts more than 150 of them. Astronomers used to think that stars in a GC form from the same molecular cloud, but now they know that that’s not true. GCs contain stars of different ages and metallicities.

GCs are different from their cousins, the open clusters (OCs). OCs are most often found in the disks of spiral galaxies, have more heavy elements, and are less dense and also smaller than GCs. OCs have only a few thousand stars, and there are more than 1100 of them in the Milky Way.

NGC 6441 is one of the most luminous and massive globular clusters in the Milky Way. Image Credit: ESA/Hubble & NASA, G. Piotto
NGC 6441 is one of the most luminous and massive globular clusters in the Milky Way. Image Credit: ESA/Hubble & NASA, G. Piotto

GCs are unique, and astronomers consider them tracers of galactic evolution. Thanks largely to the ESA’s Gaia spacecraft, we know more about GCs. Gaia helped reveal the presence of numerous stellar streams coming from the Milky Way’s globular clusters. As the authors explain in their paper, “These drawn-out associations of stars on similar orbits are likely debris from disrupted dwarf galaxies and their GCs, shorn off by Galactic tides during accretion by the MW (Milky Way.)”

Gaia did more than spot these streams. It was able to connect some streams to specific GCs. “Gaia’s exquisite kinematic data has firmly tied the origins of ~10 especially thin streams to specific MWGCs,” the authors write. The Palomar 5 GC and its streams are well-known examples. The streams are excellent tracers of the Milky Way’s evolution. (Palomar 5 gained even more notoriety in astronomy recently when a 2021 paper found more than 100 black holes in its center.)

Observations of these types of tails, both from stars ejected from GCs, and from interacting and merging galaxies, are an extremely active area of research. There are many astounding images of these interactions. But as the authors point out, “… the theoretical study of stellar escape from GCs has a longer history.” Astronomers have come up with different mechanisms for these escapes, and this paper starts with a review of each one.

Artist's impression of the thin stream of stars torn from the Phoenix globular cluster, wrapping around our Milky Way (left). Red giant stars make up a significant portion of the stream and helped astronomers map it. Credit: James Josephides (Swinburne Astronomy Productions) and the S5 Collaboration.
Artist’s impression of the thin stream of stars torn from the Phoenix globular cluster, wrapping around our Milky Way (left). Red giant stars make up a significant portion of the stream and helped astronomers map it. Credit: James Josephides (Swinburne Astronomy Productions) and the S5 Collaboration.

The authors divide escape mechanisms into two categories: Evaporation and Ejection. Evaporation is gradual, while ejection is more abrupt. The following are brief descriptions of each of the ejection methods, beginning with the Evaporation category.

Two-Body Relaxation: the motions of each body induce granular perturbations that create exchanges in energy and momentum in the bodies. Over time, stars can be ejected from GCs.

Cluster mass loss: stars lose mass over time, and that can affect the gravitational binding that holds stars in the cluster.

Sharply time-dependent tides: MWGCs orbit the Milky Way in eccentric and inclined orbits. The galactic tide will be stronger at some points in the orbit. The changing gravity can allow stars to exit the GCs.

The second broad category is Ejection. These are events typically involving single stars that are ejected rapidly and dramatically.

Strong Encounters: a close passage between two or more bodies that provides a strong enough kick to eject a star.

(Near)-Contact Recoil: encounters so close that tides, internal stellar processes, and/or relativistic effects are relevant. This includes collisions and gravitational waves.

Stellar Evolution Recoil: This includes the powerful forces unleashed when a star goes supernova, for example, or when a black hole or neutron star is formed.

Since there was no way to go and observe a statistically significant number of GC ejections, the team of researchers took what data was available and performed simulations. They used what’s called the CMC Cluster Catalog.

The study is concerned with the two types of GCs: non-core collapsed and core-collapsed. They’re different from each other and are a fundamental property of GCs, so the team simulated both types.

Core collapse in GCs occurs when the more massive stars in a GC encounter less massive stars. This creates a dynamic process that, over time, drives some stars out of the center of the GC towards the outside. This creates a net loss of kinetic energy in the core, so the remaining stars in the GCs core take up less space, creating a collapsed core.

This figure from the study shows the number of escaped single stars and stellar objects for the archetypal core-collapse GCs and non-core-collapse GCs. The x-axis is unlabelled but measures time in Gyrs. Each black marker is two Gyrs. Dashed lines are results from core-collapsed GCs, while solid lines are non-core-collapsed GCs. The plotted lines are colour coded according to the legend at the top. As the figure shows, most ejected stars are main-sequence stars, mirroring the population of the GCs themselves. Image Credit: Weatherford et al. 2022.
This figure from the study shows the number of escaped single stars and stellar objects for the archetypal core-collapse GCs and non-core-collapse GCs. The x-axis is unlabelled but measures time in Gyrs. Each black marker is two Gyrs. Dashed lines are results from core-collapsed GCs, while solid lines are non-core-collapsed GCs. The plotted lines are colour coded according to the legend at the top. As the figure shows, most ejected stars are main-sequence stars, mirroring the population of the GCs themselves. Image Credit: Weatherford et al. 2022.

An important astronomical principle plays a role in the team’s results. Two-body relaxation is a fundamental aspect of stellar associations that has far-reaching effects. It’s a complicated topic, but it basically describes the ways that stars in stellar associations, such as GCs, interact gravitationally and share kinetic energy with each other. It shows that star-to-star interactions drive GCs to evolve during the lifetime of the galaxy they’re attached to.

Not surprisingly, the researchers found that two-body relaxation plays a powerful role. That conclusion lines up with the established theory. “Consistent with longstanding theory and numerical modelling, we find that two-body relaxation in the cluster core dominates the overall escape rate,” they write.

This figure from the study shows binary objects ejected in the simulation. The number of objects is on the y-axis, and time in two-Gyr increments is on the x-axis. Dashed lines are results from core-collapsed GCs, while solid lines are non-core-collapsed GCs. Image Credit: Weatherford et al. 2022.
This figure from the study shows binary compact objects ejected in the simulation. The number of objects is on the y-axis, and time in two-Gyr increments is on the x-axis. Dashed lines are results from core-collapsed GCs, while solid lines are non-core-collapsed GCs. Image Credit: Weatherford et al. 2022.

They also found that “… central strong encounters involving binaries contribute especially high-speed
ejections, as do supernovae and gravitational wave-driven mergers.” This also lines up with other research.

This figure from the study shows binary objects containing a compact object and a main-sequence or giant star ejected from GCs. The number of objects is on the y-axis, and time in two-Gyr increments is on the x-axis. Dashed lines are results from core-collapsed GCs, while solid lines are non-core-collapsed GCs. Image Credit: Weatherford et al. 2022.
This figure from the study shows binary objects containing a compact object and a main-sequence or giant star ejected from GCs. The number of objects is on the y-axis, and time in two-Gyr increments is on the x-axis. Dashed lines are results from core-collapsed GCs, while solid lines are non-core-collapsed GCs. Image Credit: Weatherford et al. 2022.

But one of their results is new. It concerns three-body binary formation (3BBF.) 3BBF is when three bodies collide to form a new binary object. “We have also shown for the first time that three-body binary formation plays a significant role in the escape dynamics of non-core-collapsed GCs typical of those in the MW. BHs are an essential catalyst for this process,” they write. “3BBF dominates the rate of present-day high-speed ejections over any other mechanism,” they explain, as long as significant numbers of BHs remain in the GCs core. 3BBFs also produce a significant number of hypervelocity stars.

In their conclusion, the authors explain that “… this study provides a broad sense of the escape mechanisms and demographics of escapers from GCs,” while also noting that the results are “not immediately comparable to Gaia observations.” That’s why this work is the first in a series of papers. In their follow-up paper, they intend to integrate the trajectories of escaped stars and construct their velocity distributions to reproduce tidal tails. After that work, they hope that they’ll have a clearer understanding of how stars escaping from GC contribute to galactic evolution.

In a third paper, they intend to “… identify likely past members (‘extratidal candidates’) of specific MWGCs and directly compare the mock ejecta from our cluster models to the Gaia data.” This will get closer to some of the core questions surrounding GCs and the Milky Way’s evolution: how do stellar streams form? How many BHs are there in GCs? What role do supernovae play?

“Ultimately, we hope to better understand stellar stream formation and, in an ideal case, leverage the new
observables from Gaia to better constrain uncertain properties about MWGCs, such as BH content, SNe kicks, and the initial mass function, which affect ejection velocities and the cluster evaporation rate.”

The ESA's Gaia spacecraft doesn't make a lot of headlines in regular media because it doesn't take gorgeous images. But as this study shows, its contribution to important topics like galactic evolution can't be overstated. Artist's impression of the ESA's Gaia Observatory. Credit: ESA
The ESA’s Gaia spacecraft doesn’t make a lot of headlines in regular media because it doesn’t take gorgeous images. But as this study shows, its contribution to important topics like galactic evolution can’t be overstated. (Those who know, know.) Artist’s impression of the ESA’s Gaia Observatory. Credit: ESA

This study is an interesting look at how a number of natural phenomena all contribute to galactic evolution. The evolution of individual stars, how individual stars interact gravitationally and how they form binary objects, the tidal interactions between globular clusters and their host galaxies, two-body relaxation, and even three-body binary formation. Throw in supernovae and hypervelocity stars.

Each one of these topics can form the basis of an entire career in astrophysics. It’s easy to see why follow-up studies are needed. Once they’re completed, we’ll have a much better picture of how galaxies, specifically our own Milky Way, evolve.

More:

Adblock test (Why?)



Source link

Continue Reading

Science

How to see Mars at its brightest at opposition this week

Published

 on

Stargazers in the northern hemisphere are in for a treat this week as Mars has reached its closest point to Earth, giving the best view of the red planet until the 2030s. Mars made its closest approach to Earth on the night of November 30 to December 1, but the best views are yet to come as the planet reaches a point called opposition on the night of December 7 to December 8. Opposition is when Mars is directly opposite the sun as seen from Earth, which means this is when Mars will be at its brightest.

The reason that the closest approach and opposition are a few days apart is because of the elliptical nature of the planets’ orbits. Neither Earth nor Mars orbits in a perfect circle around the sun, so there are times when they are a little closer or a little further away. These small differences account for the few days’ delay between closest approach and opposition. The elliptical nature of Mars’s orbit is also why there will be such a great view of the planet this week. Mars won’t come back this close to Earth until 2033.

Finder chart for Mars on 8 December. Stuart Atkinson

This diagram from the U.K.’s Royal Astronomy Society shows how to locate Mars in the night sky on the evening of December 8. Mars should be one of the brightest objects in the skies, so if you’re lucky to have clear weather overhead at night then you should easily be able to spot the planet with binoculars or a telescope. At this time, Mars will be around 50 million miles away.

December 8 is also a great time to look for Mars as you may be able to spot the moon moving in front of the planet, called an occultation, depending on where in the northern hemisphere you are located. For exact times to look out for this event by U.S. region, head over to Sky and Telescope for more information.

Genius Dog 336 x 280 - Animated

According to Sky at Night magazine, you should be able to observe Mars using almost any telescope, but adding a Barlow lens to your setup will give you a better view and enhance the darker and lighter patches on the planet. You may be able to see features on Mars like its polar ice caps, its patches of light and dark which are called albedo features, and perhaps even certain large geological features like basins and plains.

Some of the most dramatic views of Mars will be on the night of December 8, but if that doesn’t work out for you then you should also look to the skies in the week before and after this date as you should still be able to get a good view then.

Source link

Continue Reading

Trending