The number of lightning strikes has been significantly affected by solar activity, according to new research.The Sun’s magnetic field is bending the Earth’s own field, increasing our exposure to cosmic rays.These rays are believed to increase the number of thunderclouds and trigger lightning bolts in some locations.The manner is which lightning bolts are triggered has long puzzled scientists as the air is known to be a good insulator of electricity.Something else needs to come into play to conduct the electrical charges built up in thunder clouds down to the ground.Since the 1990s, researchers have speculated that the magnetic activity of the Sun could be linked to lightning on Earth.Current theories hold that high energy particles called galactic cosmic rays provide the necessary link that lets the current flow into a lightning bolt.This latest work suggests that the orientation of the Sun’s magnetic field is playing a significant role in the number of strikes.The researchers believe the field is like a bar magnet, so as our star spins around sometimes the field points towards the Earth and sometimes away.
Black holes can’t be seen but they can be detected by their “exhaust.” The gravity of black holes causes material to swirl around, heating up as it gets closer and spins faster until it’s glowing white hot. A closer look at the spacing of these quasars also revealed they were not evenly distributed.A European space observatory picked up an unusual signal which astronomers believe to be the first direct detection of dark matter’s signature. The finding could be a historic breakthrough in our understanding of the universe.Invisible dark matter – which neither emits or absorbs light – is believed to account for 85 percent of the matter in the universe, and is thought to explain the gravitational pull that keeps galaxies from flying apart.
Astronomers have discovered that the black holes at the center of some galaxies are strangely aligned with other black holes across billions of light years in distance. Scientists think the new discovery could provide answers about how cosmic rays are produced, and solve a key mystery about how the universe operates. The answers came from fresh data gathered at the Very Large Telescope (VLT) in Chile by a team of scientists from the University of Liege, Belgium, showing the unusual alignment between the enormous interstellar objects called “quasars” – also known as a galaxy with a supermassive black hole at its center.
I had the sky, up there, all speckled with stars, and I used to lay on my backs and look up at them, and discuss about whether they was made, or only just happened. I have . . . a terrible need . . . shall I say the word? . . . of religion. Then I go out at night and paint the stars.
To make an apple pie, you need wheat, apples, a pinch of this and that, and the heat of the oven. The ingredients are made of molecules – sugar, say, or water. The molecules, in turn, are made of atoms – carbon, oxygen, hydrogen and a few others. Where do these atoms come from? Except for hydrogen, they are all made in stars. A star is a kind of cosmic kitchen inside which atoms of hydrogen are cooked into heavier atoms. Stars condense from interstellar gas and dust, which are composed mostly of hydrogen. But the hydrogen was made in the Big Bang, the explosion that began the Cosmos. If you wish to make an apple pie from scratch, you must first invent the universe.
Suppose you take an apple pie and cut it in half; take one of the two pieces, cut it in half; and, in the spirit of Democritus, continue. How many cuts before you are down to a single atom? The answer is about ninety successive cuts. Of course, no knife could be sharp enough, the pie is too crumbly, and the atom would in any case be too small to see unaided.
At Cambridge University in England, in the forty-five years centered on 1910, the nature of the atom was first understood – partly by shooting pieces of atoms at atoms and watching how they bounce off. A typical atom has a kind of cloud of electrons on the outside. Electrons are electrically charged, as their name suggests. The charge is arbitrarily called negative. Electrons determine the chemical properties of the atom – the glitter of gold, the cold feel of iron, the crystal structure of the carbon diamond. Deep inside the atom, hidden far beneath the electron cloud, is the nucleus, generally composed of positively charged protons and electrically neutral neutrons. Atoms are very small – one hundred million of them end to end would be as large as the tip of your little finger. But the nucleus is a hundred thousand times smaller still, which is part of the reason it took so long to be discovered. Nevertheless, most of the mass of an atom is in its nucleus; the electrons are by comparison just clouds of moving fluff. Atoms are mainly empty space. Matter is composed chiefly of nothing.
I am made of atoms. My elbow, which is resting on the table before me, is made of atoms. The table is made of atoms. But if atoms are so small and empty and the nuclei smaller still, why does the table hold me up? Why, as Arthur Eddington liked to ask, do the nuclei that comprise my elbow not slide effortlessly through the nuclei that comprise the table? Why don’t I wind up on the floor? Or fall straight through the Earth?
The answer is the electron cloud. The outside of an atom in my elbow has a negative electrical charge. So does every atom in the table. But negative charges repel each other. My elbow does not slither through the table because atoms have electrons around their nuclei and because electrical forces are strong. Everyday life depends on the structure of the atom. Turn off the electrical charges and everything crumbles to an invisible fine dust. Without electrical forces, there would no longer be things in the universe – merely diffuse clouds of electrons, protons and neutrons, and gravitating spheres of elementary particles, the featureless remnants of worlds.
When we consider cutting an apple pie, continuing down beyond a single atom, we confront an infinity of the very small. And when we look up at the night sky, we confront an infinity of the very large. In a burnt apple pie, the char is mostly carbon. Ninety cuts and you come to a carbon atom, with six protons and six neutrons in its nucleus and six electrons in the exterior cloud. If we were to pull a chunk out of the nucleus – say, one with two protons and two neutrons – it would be not the nucleus of a carbon atom, but the nucleus of a helium atom. Such a cutting or fission of atomic nuclei occurs in nuclear weapons and conventional nuclear power plants, although it is not carbon that is split. If you make the ninety-first cut of the apple pie, if you slice a carbon nucleus, you make not a smaller piece of carbon, but something else – an atom with completely different chemical properties. If you cut an atom, you transmute the elements.
But suppose we go farther. Atoms are made of protons, neutrons and electrons. Can we cut a proton? If we bombard protons at high energies with other elementary particles – other protons, say – we begin to glimpse more fundamental units hiding inside the proton. Physicists now propose that so-called elementary particles such as protons and neutrons are in fact made of still more elementary particles called quarks, which come in a variety of ‘colors’ and ‘flavors’, as their properties have been termed in a poignant attempt to make the subnuclear world a little more like home. Are quarks the ultimate constituents of matter, or are they too composed of still smaller and more elementary particles? Will we ever come to an end in our understanding of the nature of matter, or is there an infinite regression into more and more fundamental particles? This is one of the great unsolved problems in science…..
The rising and falling of the surf is produced in part by tides. The Moon and the Sun are far away. But their gravitational influence is very real and noticeable back here on Earth. The beach reminds us of space.
Fine sand grains, all more or less uniform in size, have been produced from larger rocks through ages of jostling and rubbing, abrasion and erosion, again driven through waves and weather by the distant Moon and Sun. The beach also reminds us of time. The world is much older than the human species.
A handful of sand contains about 10,000 grains, more than the number of stars we can see with the naked eye on a clear night. But the number of stars we can see is only the tiniest fraction of the number of stars that are. What we see at night is the merest smattering of the nearest stars. Meanwhile the Cosmos is rich beyond measure: the total number of stars in the universe is greater than all the grains of sand on all the beaches of the planet Earth.
Despite the efforts of ancient astronomers and astrologers to put pictures in the skies, a constellation is nothing more than an arbitrary grouping of stars composed of intrinsically dim stars that seem to us bright because they are nearby, and intrinsically brighter stars that are somewhat more distant. All places on Earth are, to high precision, the same distance from any star. This is why the star patterns in a given
constellation do not change as we go from, say, Soviet Central Asia to the American Midwest. The stars in any constellation are all so far away that we cannot recognize them as a three-dimensional configuration as long as we are tied to Earth.
The average distance between the stars is a few light-years, a light-year being, we remember, about ten trillion kilometers. For the patterns of the constellations to change, we must travel over distances comparable to those that separate the stars; we must venture across the light-years. Then some nearby stars will seem to move out of the constellation, others will enter it, and its configuration will alter dramatically.
The solar neighborhood, the immediate environs of the Sun in space, includes the nearest star system, Alpha Centauri. It is really a triple system, two stars revolving around each other, and a third, Proxima Centauri, orbiting the pair at a discreet distance. At some positions in its orbit, Proxima is the closest known star to the Sun – hence its name. Most stars in the sky are members of double or multiple star systems. Our solitary Sun is something of an anomaly. The second brightest star in the constellation Andromeda, called Beta Andromedae, is seventy-five light-years away. The light by which we see it now has spent seventy-five years traversing the dark of interstellar space on its long journey to Earth. When the light set out on its long voyage, the young Albert Einstein, working as a Swiss patent clerk, had published his epochal special theory of relativity here on Earth. Space and time are interwoven. We cannot look out into space without looking back into time. Light travels very fast. But space is very empty, and the stars are far apart. Distances of seventy-five light-years or less are very small compared to other distances in astronomy. From the Sun to the center of the Milky Way Galaxy is 30,000 light-years.