Dark Matter Does Not Exist

For centuries, scientists have grappled with the fundamental forces that govern our universe, chief among them being gravity, and more recently, dark matter.

Gravity is the invisible force that attracts objects with mass towards each other, playing a crucial role in shaping the cosmos, from the formation of galaxies to the orbits of planets.

However, as our understanding of the universe has expanded, so too have the mysteries surrounding it.

Dark matter dilemma
One of the most perplexing of these mysteries is the concept of dark matter, a hypothetical form of matter that is believed to make up a significant portion of the universe’s total mass.

Unlike ordinary matter, which we can see and interact with directly, dark matter does not emit, absorb, or reflect light, making it invisible to telescopes and other detecting instruments.  READ MORE...

Defining Our Physical Universe

On the smallest of physical scales, we have the fundamental, elementary particles, which build up to assemble nuclei, atoms, molecules, and even larger structures. 

On larger scales, we have planets, stars, stellar systems, galaxies, clusters of galaxies, and vast voids between them, all contributing to the enormous cosmic web.

Overall, there are many different scales to view the Universe on. Here's the grand cosmic tour, from the extremely tiny to the unfathomably large.



Our Universe spans from subatomic to cosmic scales.
The journey from macroscopic scales down to subatomic ones spans many orders of magnitude, but going down in small steps can make each new one more accessible from the previous one. Humans are made of organs, cells, organelles, molecules, atoms, then electrons and nuclei, then protons and neutrons, and then quarks and gluons inside of them. This is the limit to how far we’ve ever probed nature.Credit: Magdalena Kowalska/CERN/ISOLDE team

All told, 13 different scales are presently known.
On the right, the gauge bosons, which mediate the three fundamental quantum forces of our Universe, are illustrated. There is only one photon to mediate the electromagnetic force, there are three bosons mediating the weak force, and eight mediating the strong force. This suggests that the Standard Model is a combination of three groups: U(1), SU(2), and SU(3), whose interactions and particles combine to make up everything known in existence. With gravity thrown into the mix, there are a total of 26 fundamental constants required to explain our Universe, with four big questions still awaiting explanation.Credit: Daniel Domingues/CERN

1.) Fundamental, elementary particles. Down to 10-19 meters, these quanta have never been divided.
When two protons, each one made of three quarks held together by gluons, overlap, it’s possible that they can fuse together into a composite state dependent on their properties. The most common, stable possibility is to produce a deuteron, made of a proton and a neutron, which requires the emission of a neutrino, a positron, and possibly a photon as well.Credit: Keiko Murano

2.) Nuclear scales. On femtometer (~10-15 m) scales, individual nucleons, composed of quarks and gluons, bind together.
Although you yourself are made of atoms, what you experience as “touch” doesn’t necessarily require another, external atom to come in actual overlapping contact with the atoms in your body. Simply getting close enough to exert a force is not only enough, it’s what most commonly occurs.        READ MORE...

Raining Diamonds Across the Universe

Uranus and Neptune, ice giants where scientists believe diamond rain falls below the surface.

It could be raining diamonds on planets throughout the universe, scientists suggested Friday, after using common plastic to recreate the strange precipitation believed to form deep inside Uranus and Neptune.

Scientists had previously theorized that extremely high pressure and temperatures turn hydrogen and carbon into solid diamonds thousands of kilometers below the surface of the ice giants.

Now new research, published in Science Advances, inserted oxygen into the mix, finding that "diamond rain" could be more common than thought.

Ice giants like Neptune and Uranus are thought to be the most common form of planet outside our Solar System, which means diamond rain could be occurring across the universe.

Dominik Kraus, a physicist at Germany's HZDR research lab and one of the study's authors, said that diamond precipitation was quite different to rain on Earth.

Under the surface of the planets is believed to be a "hot, dense liquid", where the diamonds form and slowly sink down to the rocky, potentially Earth-size cores more than 10,000 kilometers (6,200 miles) below, he said.

There fallen diamonds could form vast layers that span "hundreds of kilometers or even more", Kraus told AFP.

While these diamonds might not be shiny and cut like a "a nice gem on a ring", he said they were formed via similar forces as on Earth.

Aiming to replicate the process, the research team found the necessary mix of carbon, hydrogen and oxygen in a readily available source—PET plastic, which is used for everyday food packaging and bottles.

Kraus said that while the researchers used very clean PET plastic, "in principle the experiment should work with Coca-Cola bottles".  READ MORE...

Watching Space in High Definition

This artist’s view shows a planet orbiting the young star Beta Pictoris. 

(Image credit: ESO L. Calçada/N. Risinger)

Researchers are looking forward to a glimpse of colliding worlds in action from NASA's cutting-edge space observatory.

After the James Webb Space Telescope finishes its commissioning period and releases its first operational images on July 12, the observatory will dive into science in earnest. And one of the telescope's first-year investigations will include a close-up view of the strange neighborhood of Beta Pictoris.

The young star, just 63 light years away from us, is surrounded by a dusty disc full of debris left over from its formation. It's a crowded space, hosting "at least two planets [and] a jumble of smaller, rocky bodies," researchers said in a 2021 press release(opens in new tab) about the investigation.

While the research has numerous directions, one key aspect is watching a young planetary system evolving as planetesimals (the predecessors to planets) collide. Because Beta Pictoris is wreathed in dust, researchers will be using Webb's infrared light to peer through the debris and see what is happening in high definition.

Webb will have decades of past work to draw upon, including ground-based observatories and space observations from the Hubble Space Telescope. We know from such studies that Beta Pictoris hosts at least two gigantic planets, both much more massive than Jupiter. Researchers also glimpsed the first known exocomets, or comets beyond our solar system, whirling in the debris cloud.  READ MORE...

How Fast are we Moving?

No matter what perspective you choose to look at it from, planet Earth is always in motion. Our planet rotates on its axis continuously, spinning and completing a full 360° rotation approximately once a day. As we spin, we also revolve around the Sun, completing a nearly 1 billion kilometer journey every single year. Moreover, the entire Solar System — Sun, planets, moons, and all — moves through the Milky Way galaxy, orbiting around the galactic center on timescales far greater than humanity has existed for. And finally, the Milky Way galaxy moves within the Local Group, which itself moves through intergalactic space.

Depending on what we’re measuring our motion relative to, we can quantify just how quickly planet Earth moves through the Universe. Even though our motion is barely detectable through the experiments we can perform here on Earth, a look out at the Universe enables us to understand precisely how we’re in motion on each and every scale. Here’s how we know what our cosmic motion is, from each individual component to the entire cumulative effects of everything combined.

This view of the Earth comes to us courtesy of NASA’s MESSENGER spacecraft, which had to perform flybys of Earth and Venus in order to lose enough energy to reach its ultimate destination: Mercury. The round, rotating Earth and its features are undeniable, as this rotation explains why Earth bulges at the center, is compressed at the poles, and has different equatorial and polar diameters.(Credit: NASA/MESSENGER)

How fast does the Earth spin?
This question, although it might seem simple, has a different answer dependent on where, precisely, you are on the planet’s surface. Planet Earth is a rigid body, meaning that the land masses remain relatively constant with respect to one another over time. As the Earth rotates about its axis, practically every point on the surface completes a full rotation in just under 24 hours: 23 hours, 56 minutes, and 4.09 seconds, to be precise.  READ MORE...

Searching For Alien Life

Is mankind alone in the universe? Or are there somewhere other intelligent beings looking up into their night sky from very different worlds and asking the same kind of question? Are there civilizations more advanced than ours, civilizations that have achieved interstellar communication and have established a network of linked societies throughout our galaxy? 

Such questions, bearing on the deepest problems of the nature and destiny of mankind, were long the exclusive province of theology and speculative fiction. Today for the first time in human history they have entered into the realm of experimental science.

From the movements of a number of nearby stars we have now detected unseen companion bodies in orbit around them that are about as massive as large planets. From our knowledge of the processes by which life arose here on the earth we know that similar processes must be fairly common throughout the universe. 

Since intelligence and technology have a high survival value it seems likely that primitive life forms on the planets of other stars, evolving over many billions of years, would occasionally develop intelligence, civilization and a high technology. Moreover, we on the earth now possess all the technology necessary for communicating with other civilizations in the depths of space. Indeed, we may now be standing on a threshold about to take the momentous step a planetary society takes but once: first contact with another civilization..

In our present ignorance of how common extraterrestrial life may actually be, any attempt to estimate the number of technical civilizations in our galaxy is necessarily unreliable. We do, however, have some relevant facts. There is reason to believe that solar systems are formed fairly easily and that they are abundant in the vicinity of the sun.  In our own solar system, for example, there are three miniature "solar systems": the satellite systems of the planets Jupiter (with 13 moons), Saturn (with 10) and Uranus (with five). 

The only technique we have at present for detecting the planetary systems of nearby stars is the study of the gravitational perturbations such planets induce in the motion of their parent star. Imagine a nearby star that over a period of decades moves measurably with respect to the background of more distant stars. Suppose it has a nonluminous companion that circles it in an orbit whose plane does not coincide with our line of sight to the star. 

Both the star and the companion revolve around a common center of mass. The center of mass will trace a straight line against the stellar background and thus the luminous star will trace a sinusoidal path. From the existence of the oscillation we can deduce the existence of the companion. Furthermore, from the period and amplitude of the oscillation we can calculate the period and mass of the companion. The technique is only sensitive enough, however, to detect the perturbations of a massive planet around the nearest stars.  TO READ MORE, CLICK HERE...