like a physicist

cwnl:

Now Entering The Exoplanet Catalog: Kepler-20e & Kepler-20f

Two Earth-Size Alien Planets, the Smallest Exoplanets Yet

Imaged Above: An artist’s rendering of the newfound alien planet Kepler-20e, which scientists say is smaller than Earth, at about 0.87 times the width of our planet. Credit: NASA/JPL-Caltech/T. Pyle

Two planets orbiting a star 950 light-years from Earth are the smallest, most Earth-size alien worlds known, astronomers announced today (Dec. 20). One of the planets is actually smaller than Earth, scientists say.

These planets, while roughly the size of our planet Earth, are circling very close to their star, giving them fiery temperatures that are most likely too hot to support life, researchers said. The discovery, however, brings scientists one step closer to finding a true twin of Earth that may be habitable.

“We’ve crossed a threshold: For the first time, we’ve been able to detect planets smaller than the Earth around another star,” said lead researcher François Fressin of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. “We proved that Earth-size planets exist around other stars like the sun, and most importantly, we proved that humanity is able to detect them. It’s the beginning of an era.”

To discover the new planets, Fressin and his colleagues used NASA’s Kepler space telescope, which noticed the tiny dips in the parent star’s brightness when the planets passed in front of it, blocking some of its light (this is called the transit method). The researchers then used ground-based observatories to confirm that the planets actually exist by measuring minute wobbles in the star’s position caused by gravitational tugs from its planets.

Latest Fermi studies find no trace of dark matter

Independent analyses of data from the Fermi Gamma-ray Space Telescope have found no trace of low-mass dark matter – the mysterious substance thought to make up much of the universe. The results appear to go against recent direct evidence for low-mass dark matter, although some physicists believe there is no conflict.

Dark matter is an invisible substance thought to make up nearly a quarter of the mass/energy of the universe. While its gravitational pull is needed to explain the properties of massive structures such as galaxies, it does not interact strongly with light and has therefore yet to be observed directly. The most popular candidates for dark matter are so-called weakly interacting massive particles (WIMPs). To spot these WIMPs directly, researchers have built detectors in underground labs where the low background noise ought to allow any signals to stand out. These detector experiments include DAMA and CRESST, both based underground at the Gran Sasso laboratory in central Italy, and CoGeNT, based in the Soudan mine in the US.

scinerd:

This is a component of the James Webb Space Telescope (JWST) primary mirror. Overall, the mirror will consist of 18 of these components. As a figure of reference, the Hubble Space Telescope primary mirror is about the size of 3 or 4 of these pieces, and we’ve all see the image quality which that provides.

JWST was almost cancelled recently after budget troubles, but thankfully further funding has been confirmed. The funding cut was proposed despite 75% of the telescope having either been already completed or undergoing testing.

quantumaniac:

Antimatter 

All objects that we can see on and from Earth are composed of regular, everyday matter. This matter is composed of atoms, which are composed of particles; protons, neutrons, electrons and the like. Similarly, antimatter is composed of antiparticles; such as positrons, antiprotons and antineutrons. These antiparticles are, of course, composed of antiquarks. Antiparticles can even collect together to form antiatoms! Thus, all of our matter-composed elements are possible with antimatter - antihydrogen for example. 

In an antiparticle, charge must be opposite, and mass must be basically exactly the same. Electrically neutral particles aren’t identical to their anti-counterparts, since they are still composed of antiquarks and antiparticles. 

In 1928, Paul Dirac paved the first path to antimatter when he predicted positrons. Antimatter is not just a theoretical mathematical anomaly - it exists in nature. Antiparticles are created during beta decay, and in the interaction of cosmic rays (most notably gamma rays) and Earth’s atmosphere. Due to our universe’s conservation of charge, it is not possible to create an antiparticle without creating a particle of opposite charge or destroying a particle of the same charge. However, some (typically near or exactly massless) particles are their own antiparticles, such as photons, the theorized gravitons and some WIMPs.

Interestingly, when matter and antimatter collide - annihilation occurs. The collision can produce such emissions as high-energy photons (gamma rays,) or even other particle-antiparticle pairs. The particles that are their own antiparticles, such as gravitons and photons, can even annihilate with themselves! One of the greatest mysteries in Physics today is that, since this collision occurs, why the universe seems to be composed of mostly matter. In a process called baryogenesis, an asymmetry has occurred in the universe between matter and antimatter - and scientists are working hard as we speak to figure out why that is.  

trulydiscombobulated:

Albert Einstein and Edwin Hubble

galaxyshmalaxy:

C.U.A.S Telescope (by Nathan Petersen)

princesssylviap:

This image, released April 29, 2004, of the Bug Nebula (NGC 6302) taken with the NASA/ESA Hubble Space Telescope, shows impressive walls of compressed gas, laced with trailing strands and bubbling outflows.

Source: Reuters/NASA