Astronomers discover a star-creating galaxy that sheds light on the galactic cooling problem

Massive galaxy cluster spawns more than 700 stars a year

A newly discovered cluster of galaxies, more than 5 billion light years from Earth…is among the most massive clusters of galaxies in the universe, and produces X-rays at a rate faster than any other known cluster.

It also creates new stars at an “unmatched” pace of more than 700 per year, said Michael McDonald. “This extreme rate of star formation was unexpected,” he said during a NASA news conference Wednesday, noting that the Milky Way forms just one or two stars a year.

In addition to being massive, unique, and the biggest star-nursery in the universe, this area, called Phoenix, also helps theorists with something, the galactic cooling problem.

 

Phoenix Cluster: a combination of the X-ray, Optical, and Ultraviolet images, left; artists concept of the central galaxy, right. (photo: NASA)

 

For years scientists have been coming up with explanations for how stars are formed. The earliest being a mass of molecules would collapse in on themselves as fusion begins. The mass would then accumulate until its gravity becomes strong enough to spin, turn into a sphere, and pull on everything around it, collecting planets, asteroids, and other debris into its solar system.

But, this doesn’t take into account thermodynamics, specifically why doesn’t the star expand as it heats up. Indeed, several half-stars were observed in the universe stuck in this state of expansion unable to contract into the ultra-compact ball of a star.

That’s where a new theory comes in, the galactic “cooling flow”.

**There appears to be no name for the theory, all references are to a general theory theory of star formation.

This says the creation of stars is a lot like an explosion, with an initial burst of heat which then dissipates bringing cool air back into the explosion zone. In this case, thermonuclear fusion ignites much of the galaxy and begins sucking into the center lots of mass, including the surrounding galaxies.

As the (star) forms, this plasma initially heats up due to the gravitational energy released from the infall of smaller galaxies.

As the gas cools, it should condense and sink inward, a process known as a “cooling flow.” 

In the cluster’s center, this cooling flow can lead to very dense cores of gas, termed “cool cores,” which should fuel bursts of star formation in all clusters that go through this process. Most of these predictions had been confirmed with observations – the X-ray glow, the lower temperatures at the cluster centers – but starbursts accompanying this cooling remain rare. – TG Daily

 

A step forward in our knowledge of star formation, but something tells me we are not there yet.

Continue reading Astronomers discover a star-creating galaxy that sheds light on the galactic cooling problem

What is the Higgs boson and why does it matter? (in simple terms)

What is the Higgs boson and why does it matter? (in simple terms)

If you remember basic chemistry, the atom is made up a proton, neutron, and electron. Those were the basic building blocks of life when I was a kid. I remember illustrations showing the neutron and proton in the center with the electron orbiting around it.

In the 1960’s several physicists starting thinking about things smaller than atoms, called sub-atomic. They developed several theories about these sub-atoms until the 1970s, when one model stood out. This is called the Standard Model of physics.

In that model, there are 12 particles and 4 forces. The particles are called quarks and leptons, and the forces are called – strong, weak, gravity, and electromagnetic.

The forces are the most important because they describe some pretty amazing things. For example, the electromagnetic force is carried by a particle of light, called a photon. The photon has infinite range and great strength, giving the light of stars the ability to travel thousands of light years to be seen on Earth.

The force of gravity is carried by a particle called a graviton. It also has an infinite range but a very weak strength. For example, the Sun exerts a powerful pull on the Earth because it is very close, but when you get farther away that strength becomes minimal. It does not have the range that the photon does.

Both of these particles, and all of the particles that involve energy, are called bosons. These bosons are sub-atomic particles that transfer energy to each other.

Now, the interesting thing is figuring out why these photons can travel for infinite ranges, when other particles can barely keep moving.

The leading theory, calls for a Higgs field that covers the entire universe. It is an energy field made up of a particle called the Higgs boson. When a particle travels through the universe it either attracts the Higgs boson or pushes it away. If it attracts the Higgs boson then they combine to form matter and gain all the properties of mass (weight, gravity, etc.). If it repels the Higgs boson then it continues to travel as a form of energy over an infinite range (light).

The combination of the Higgs boson with other particles creates life as we know it, the matter that makes up humans, plants, rocks, etc. This is most likely the reason why it has come to be called the “God particle.”

The forces that ignore the Higgs boson do so at varying degrees. Photons of light ignore it completely. Other particles attract some Higgs bosons and slow down, eventually limiting their range and strength.

Of course, none of this was certain because scientists were unable to see the Higgs boson. Being a sub-atomic particle it is invisible to the naked eye and undetectable in a lab. It puts us in a weird predicament, how do you find something that you are not even sure exists?

CERN’s Large Hadron Collider solves that problem for us. This gigantic particle accelerator allows us to speed up particles and smash them together. Specifically, it smashes together hadrons which are multiple particles combined together.

When these particles are smashed together the scientists observe what happens. If everything acts like the Higgs theory says it does (i.e. there is a Higgs field with Higgs bosons that slow some particles but not photons), then they have proof.

With that proof the scientists of the world can move on to other more complex problems. Areas where this model falls short like with dark energy or the full theory of gravitation.

Another step in our greater understanding of the world. Each one allowing us to do more with energy, matter, and life.

 

Sources: CERN – the Standard Model, Guardian – What is the Higgs boson?, CERN – the Higgs boson, Wikipedia – Higgs boson

 

Continue reading What is the Higgs boson and why does it matter? (in simple terms)

Science Experiment: How fast can you react?

I love this piece from Scientific American, written in the format of a teaching lesson, instructing you how to perform a science experiment: How Fast Can You React?

Key concepts:
Reaction time
Neuroscience
Gravity

Introduction
Think fast! Have you ever noticed that when someone unexpectedly tosses a softball at you, you need a little time before you can move to catch it (or duck)? That’s because when your eyes see an incoming signal such as a softball, your brain needs to first process what’s happening—and thenyou can take action. In this activity, you can measure just how long it takes for you to react, and compare reaction times with your friends and family.

Materials
·    Ruler (inches or metric)
·    Paper
·    Pencil
·    Chart (below)

 

Keep readingHow Fast Can You React?

Continue reading Science Experiment: How fast can you react?

Scientists watch a black hole devour a star

Back when single-celled organisms ruled Earth, a gigantic black hole lurking quietly at the center of a distant galaxy dismantled and devoured a star.

On Wednesday, astronomers reported that they watched the whole thing unfold over a period of 15 months starting in 2010, the first time such an event had been witnessed in great detail from start to finish.

“The star got so close that it was ripped apart by the gravitational force of the black hole,” said Johns Hopkins University astronomer Suvi Gezari, lead author of a paper about the observations that was published online by the journal Nature.

***

Veering close to the black hole — about the same distance as Mercury lies from the sun — the gaseous star was stretched out and torn asunder by the black hole’s intense gravity.

“It turned into this really thin piece of spaghetti,” Gezari said.

About 76 days after the star was ripped apart, the black hole began devouring its remains, taking at least a year to finish off the meal.

***

Astronomers call these star-obliterating events tidal disruptions. The process is similar to….keep readingGiant black hole is seen gobbling up a star

How close does an object have to be to earth to be pulled by gravity?

Pulled from Quora, here is one of the best, and most popular, answers to a question. Written by Mark Eichenlaub, a graduate student in physics.

How close does an object have to be to earth to be pulled by gravity?

This question doesn’t have a direct answer because, for lack of a less-direct way of saying it, that’s not the way it works. If there were no atmosphere, you could have the ISS be just above the surface of the Earth, high enough only to clear the mountains. On the other hand, you could have something as far out as the moon, and if it weren’t going fast enough and in the right direction, it would still fall back down. The ISS doesn’t stay up because of how high it is, but because of a combination of that and how fast it’s going.

One of the most difficult things to learn about physics is the concept of force. A force in a given direction does not make things go straight in that direction. Instead, it influences the motion to be a bit more in the direction of the force than it was before.

For example, if you roll a bowling ball straight down a lane, then run up beside it and kick it towards the gutter, you apply a force towards the gutter, but the ball doesn’t go straight into the gutter. Instead it keeps going down the lane, but picks up a little bit of diagonal motion as well.

Now we can talk about an very early thought experiment in physics. Imagine you’re standing at the edge of a cliff 100m tall. If you drop a rock off, it will fall straight down. If you throw the rock out horizontally, it will fall down, but it will keep moving out horizontally as it does so, and falls at an angle. (The angle isn’t constant – the shape is a curve called a parabola, but that’s relatively unimportant here.)

The the force is straight down, but that force doesn’t stop the rock from moving horizontally. If you throw the rock horizontally harder, it goes further, and falls at a shallower angle. The force on it is the same, but the original velocity was much bigger and so the deflection is less.

Now imagine throwing the rock so hard it travels one kilometer horizontally before it hits the ground. If you do that, something slightly new happens. The rock still falls, but it has to fall more than just 100m before it hits the ground. The reason is that the Earth is curved, and so as the rock traveled out that kilometer, the Earth was actually curving away underneath of it. In one kilometer, it turns out the Earth curves away by about 10 centimeters – a small difference, but a real one.

As you throw the rock even harder than that, the curving away of the Earth underneath becomes more significant. If you could throw the rock 10 kilometers, the Earth would now curve away by 10 meters, and for a 100 km throw the Earth curves away by an entire kilometer. Now the stone has to fall a very long way down compared to the 100m cliff it was dropped from. Continue reading How close does an object have to be to earth to be pulled by gravity?

A new energy form unknown to science, Dark Energy, is expanding the Universe

The year was 1998 and two highly competitive groups of astronomers were each rushing toward the same goal: they hoped to hunt down the effects of gravitational braking in the universe. Ever since astronomers had accepted the idea of the Big Bang, they had been out hunting for its subsequent cosmic deceleration.

While the Big Bang blows space apart (it literally stretches all points of space-time away from each other), the gravitational pull of matter should, over time, slow down that initial burst of cosmic expansion.

As data was gathered and analyzed, both the Harvard and Berkeley groups were stunned to find no evidence for deceleration. Instead, everything pointed in the opposite direction.

According to observations, the expansion of the universe was speeding up — it was accelerating. Cosmic acceleration became big news.

Which means there exists a Dark Energy pushing the universe outwards:

In 1999, the newly discovered cosmic acceleration made it clear that some form of anti-gravitational energy had to exist. As nothing was known about this energy…it was called Dark Energy

The discovery of cosmic acceleration and Dark Energy upended cosmology almost overnight.

keep reading at Cosmos and Culture

 

(thx Joseph Armstrong)

What is the Dark Side of the Moon?

Does the Moon rotate?

And if the Moon rotates, why do we alway see the same side – it never seems to change.

Well, the Moon does rotate. In fact, the Moon takes 27.3 days to turn once on its axis. But the Moon also takes 27.3 days to complete one orbit around the Earth. Because the Moon’s rotation time is exactly the same amount of time it takes to complete an orbit, it always presents the same face to the Earth, and one face away (the Dark Side).

Because it only presents one face to the Earth, astronomers say that the Moon is tidally locked to the Earth. Although the Moon looks like a perfectly smooth ball, it has slight differences in the shape of its gravity field. A long time ago, the Moon did rotate. But each time it turned, the Earth’s gravity tugged at it, slowing down its rotation until it only presented one face to the Earth. At that point, the Moon was tidally locked, and from our perspective, it doesn’t seem to rotate.

Many other moons in the Solar System are also tidally locked to their planet. In fact, most of Jupiter’s large moons are tidally locked.

via Universe Today

Angry Birds in Space – NASA shows what happens to a slingshot with no gravity

It’s fun to watch the birds and pigs bounce around the International Space Station, plus check out the really cool game footage at the very end.