Connect with us

Science

Searching for the Milky Way's Black Hole – Skywatching – Castanet.net

Published

 on


When we look into the southern sky close to the horizon on summer evenings, we are looking towards the centre of our galaxy, the Milky Way.

It is lurking around 30,000 light years behind the stars making up the constellation of Sagittarius, “The Archer”. However, thanks to our location in the disc of our galaxy, our view is blocked by huge clouds of stars, gas and dust.

Our first images of the centre of the Milky Way were obtained by means of radio telescopes, which show us what the universe would look like if we could see radio waves rather than light. They revealed a strange, bright and unusually small radio source.

Measurements of the speeds stars orbit the centre of our galaxy indicate that at the same position as the bright radio source lies something very massive, very small and active. The best candidate to explain this is a black hole.

Radio waves have power to penetrate clouds and dust, which is why radar is so useful for navigation, detecting threats and avoiding hazards at night or in bad weather. However, radio waves have this greater penetration power because they are much longer than light waves. This means that to see detail when observing at radio wavelengths we need to use huge antennas.

To have the same ability to discern detail as the human eye, a radio telescope tuned to the wavelength of emissions from cosmic hydrogen (21cm) the antenna would need to be about a kilometre in diameter. Moreover, black holes are small by cosmic standards and at great distances, so to discern any details the radio telescope would need an antenna the size of the Earth.

This sounds impossible, but there is a solution, a technique called “Very Long Baseline Interferometry”.

In the 1960s, Canada was the first country to succeed in combining radio telescopes thousands of kilometres apart so that they would have the detail discerning ability of a radio telescope thousands of kilometres in diameter.

This procedure has made possible a powerful, new astronomical instrument, the Event Horizon Telescope (EHT).

Several radio telescopes, thousands of kilometres apart operate in collaboration to observe the centre of the Milky Way at the same time. One of them is the Atacama Large Millimetre Array, located in Chile, in which Canada is a partner. In addition, scientists at several Canadian universities are involved.

The collaboration is named after the boundary that forms around black holes, called the event horizon. This is a one-way boundary in space-time—stuff can fall in but nothing, not even light, gets out. This is why they are called black holes.

However, even if we cannot see the black holes directly, we can certainly see the disc of material swirling around the black holes as it gets sucked in. This stuff gets very hot, and has intense magnetic fields trapped in it, so the black hole announces itself with radio emissions and X-rays from that disc.

The first target for the Event Horizon Telescope was the galaxy M87, located some 55 million light years away. It had long been suspected that a very energetic black hole lies at its centre, a big one, around 5 billion times the mass of the Sun. The EHT gave us our first image of that black hole.

Then the EHT radio telescopes were turned on the centre of our galaxy, and got our first image of our black hole. Luckily for us, it is much less massive and active than the one at the centre of M87. At four million times the mass of the Sun, it is relatively tiny.

We believe most spiral galaxies have big black holes in their cores. It is not clear whether galaxies get them when they form or they appear later. However, learning about their roles in galaxies should tell us more about how galaxies form and evolve to the point where they develop stars and planets, and because we live in one, it would be nice to know.

•••

• Venus, Jupiter, Mars and Saturn are still lined up in the dawn glow, in order of decreasing brightness.

• The Moon will be new on May 30.

This article is written by or on behalf of an outsourced columnist and does not necessarily reflect the views of Castanet.

Adblock test (Why?)



Source link

Continue Reading

Science

Facial Recognition—Now for Seals – Hakai Magazine

Published

 on


Article body copy

Have you ever looked at a seal and thought, Is that the same seal I saw yesterday? Well, there could soon be an app for that based on new seal facial recognition technology. Known as SealNet, this seal face-finding system was developed by a team of undergraduate students from Colgate University in New York.

Taking inspiration from other technology adapted for recognizing primates and bears, Krista Ingram, a biologist at Colgate University, led the students in developing software that uses deep learning and a convolutional neural network to tell one seal face from another. SealNet is tailored to identify the harbor seal, a species with a penchant for posing on coasts in haulouts.

The team had to train their software to identify seal faces. “I give it a photograph, it finds the face, [and] clips it to a standard size,” says Ingram. But then she and her students would manually identify the nose, the mouth, and the center of the eyes.

For the project, team members snapped more than 2,000 pictures of seals around Casco Bay, Maine, during a two-year period. They tested the software using 406 different seals and found that SealNet could correctly identify the seals’ faces 85 percent of the time. The team has since expanded its database to include around 1,500 seal faces. As the number of seals logged in the database goes up, so too should the accuracy of the identification, Ingram says.

The developers of SealNet trained a neural network to tell harbor seals apart using photos of 406 different seals. Photo courtesy of Birenbaum et al.

As with all tech, however, SealNet is not infallible. The software saw seal faces in other body parts, vegetation, and even rocks. In one case, Ingram and her students did a double take at the uncanny resemblance between a rock and a seal face. “[The rock] did look like a seal face,” Ingram says. “The darker parts were about the same distance as the eyes … so you can understand why the software found a face.” Consequently, she says it’s always best to manually check that seal faces identified by the software belong to a real seal.

Like a weary seal hauling itself onto a beach for an involuntary photo shoot, the question of why this is all necessary raises itself. Ingram believes SealNet could be a useful, noninvasive tool for researchers.

Of the world’s pinnipeds—a group that includes seals, walruses, and sea lions—harbor seals are considered the most widely dispersed. Yet knowledge gaps do exist. Other techniques to track seals, such as tagging and aerial monitoring, have their limitations and can be highly invasive or expensive.

Ingram points to site fidelity as an aspect of seal behavior that SealNet could shed more light on. The team’s trials indicated that some harbor seals return to the same haulout sites year after year. Other seals, however, such as two animals the team nicknamed Clove and Petal, appeared at two different sites together. Increasing scientists’ understanding of how seals move around could strengthen arguments for protecting specific areas, says Anders Galatius, an ecologist at Aarhus University in Denmark who was not involved in the project.

Galatius, who is responsible for monitoring Denmark’s seal populations, says the software “shows a lot of promise.” If the identification rates are improved, it could be paired with another photo identification method that identifies seals by distinctive markings on their pelage, he says.

In the future, after further testing, Ingram hopes to develop an app based on SealNet. The app, she says, could possibly allow citizen scientists to contribute to logging seal faces. The program could also be adapted for other pinnipeds and possibly even for cetaceans.

Adblock test (Why?)



Source link

Continue Reading

Science

NASA launches nanosatellite in preparation for lunar 'Gateway' station – Yahoo News Canada

Published

 on


The rocket carrying the Capstone satellite lifts off. (NASA)

Nasa has launched a tiny CubeSat this week to test and orbit which will soon be used by Gateway, a lunar space station.

It’s all part of the space agency’s plan to put a woman on the moon by 2025.

The Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment (Capstone) mission launched from New Zealand on Tuesday.

Jim Reuter, associate administrator for the Space Technology Mission Directorate, said: “Capstone is an example of how working with commercial partners is key for Nasa’s ambitious plans to explore the moon and beyond.

“We’re thrilled with a successful start to the mission and looking forward to what Capstone will do once it arrives at the Moon.”

Read more: Astronomers find closest black hole to Earth

The satellite is currently in low-Earth orbit, and it will take the spacecraft about four months to reach its targeted lunar orbit.

Capstone is attached to Rocket Lab’s Lunar Photon, an interplanetary third stage that will send it on its way to deep space.

Over the next six days, Photon’s engine will periodically ignite to accelerate it beyond low-Earth orbit, where Photon will release the CubeSat on a trajectory to the moon.

Capstone will then use its own propulsion and the sun’s gravity to navigate the rest of the way to the Moon.

The gravity-driven track will dramatically reduce the amount of fuel the CubeSat needs to get to the Moon.

Read more: There might once have been life on the moon

Bradley Cheetham, principal investigator for CAPSTONE and chief executive officer of Advanced Space, “Our team is now preparing for separation and initial acquisition for the spacecraft in six days.

“We have already learned a tremendous amount getting to this point, and we are passionate about the importance of returning humans to the Moon, this time to stay!”

At the moon, Capstone will enter an elongated orbit called a near rectilinear halo orbit, or NRHO.

Once in the NRHO, Capstone will fly within 1,000 miles of the moon’s north pole on its near pass and 43,500 miles from the south pole at its farthest.

It will repeat the cycle every six-and-a-half days and maintain this orbit for at least six months to study dynamics.

“Capstone is a pathfinder in many ways, and it will demonstrate several technology capabilities during its mission timeframe while navigating a never-before-flown orbit around the Moon,” said Elwood Agasid, project manager for Capstone at Nasa’s Ames Research Center in California’s Silicon Valley.

“Capstone is laying a foundation for Artemis, Gateway, and commercial support for future lunar operations.”

Nasa estimates the cost of the whole Artemis mission at $28bn.

It would be the first time people have walked on the moon since the last Apollo moon mission in 1972.

Just 12 people have walked on the moon – all men.

Nasa flew six manned missions to the surface of the moon, beginning with Neil Armstrong and Buzz Aldrin in July 1969, up to Gene Cernan and Jack Schmitt in December 1972.

The mission will use Nasa’s powerful new rocket, the Space Launch System (SLS), and the Orion spacecraft.

Watch: NASA launch paves way for moon orbit station

Adblock test (Why?)



Source link

Continue Reading

Science

The year’s biggest and brightest supermoon will appear in July & here’s when you’ll … – Curiocity

Published

 on


Summer is here and with it? Sunshine – and some serious moonshine (of the visible variety, of course). This upcoming month, look up in anticipation of the biggest and brightest event of the year, the July Buck supermoon – which will hover over North America on July 13th.

Appearing 7% larger and lower in the sky, this particular event will be one well worth keeping an eye on when it rises above the horizon.

This will be the closest we’ll get to our celestial neighbour in 2022 (357,418 km) and while North America won’t get to see it when it reaches peak illumination at 2:38 pm ETC., it’ll still look pretty dang impressive after the sunsets.

Related Posts
You can stay in a spaceship Airbnb just a few hours from Seattle
Canada is gearing up to make crimes on the moon a thing

Not sure when the moon rises in your area? Here’s the earliest that you’ll be able to see the moon in various cities across the continent according to the Farmer’s Almanac.

  • Seattle, Washington  – 9:50 pm PDT
  • Vancouver, British Columbia – 10:02 pm PDT
  • Calgary, Alberta – 10:35 pm MST
  • Edmonton, Alberta – 10:49 pm MST
  • Toronto, Ontario – 9:34 pm MST
  • Montreal, Quebec – 9:18 pm MST

Until then, cross your fingers for a clear sky, friends! It’s going to be incredible.

Happy viewing.

JULY BUCK SUPERMOON 

When: Wednesday, July 13th

Adblock test (Why?)



Source link

Continue Reading

Trending