If you think summer is too hot or winter unbearably cold, take solace that in the distant past seasons on our planet might have been much harsher. However, the advent of milder seasons did more than offer comfort, some scientists suggest. Subdued seasonality might be linked to the emergence of complex life on Earth around 600 million years ago. On alien worlds, extreme seasonal spikes and plunges in temperature could likewise determine whether life teems, scrapes by, or dies. Seasons arise when the axis of a planet's spin is tilted relative to the plane of the planet's orbit. Recent research has suggested that a loss of axial tilt and its attendant seasonality, which helps moderate global temperatures, could doom extraterrestrial creatures. Alien Life May Not Survive on Planets With Uranus-Like Tilts
IS IT possible to tell whether a planet hosts life just from its glow? A new analysis of Earthshine, sunlight reflected off Earth then bounced back by the moon, suggests this is a viable way to seek life on exoplanets. Life co-exists with certain chemicals that leave their imprint on the light Earth reflects, while plants reflect light differently to rocks. The trouble is that exoplanets are too faint compared with their host stars for such distinctions to be detected. So Michael Sterzik of the European Southern Observatory in Santiago, Chile, and colleagues used a spectrograph mounted on the Very Large Telescope to examine polarised Earthshine, its light waves aligned in one plane. Earthshine holds clues to exoplanet aliens - space - 29 February 2012
The Solar System & Milky Way
What is Reality
Dark Energy: The Biggest Mystery in the Universe
Dark Energy FAQ | Cosmic Variance In honor of the Nobel Prize, here are some questions that are frequently asked about dark energy, or should be. What is dark energy? It’s what makes the universe accelerate, if indeed there is a “thing” that does that. (See below.) So I guess I should be asking… what does it mean to say the universe is “accelerating”?
The Story Of Dark Energy, In A Nutshell : 13.7: Cosmos And Culture Sometimes nature just throws you a loop. All your carefully laid plans, all your exquisite calculations, all your deeply held beliefs and expectations get blown away in the simple eloquence of real data from the real world. That is how Dark Energy made its appearance into the world of cosmology. Its not just that folks weren't expecting it. They were, in fact, expecting the very opposite. Last week I explained how Dark Matter was "discovered" (inferred really), based on observations over decades of the gravitational influence it exerts on matter we can see (the stuff we are made of).
Clocking galaxy clusters to gauge dark energy - space - 29 March 2012 The universe's oldest light and its largest objects could provide a new way to study dark energy, the mysterious entity believed to be pushing the universe apart at an ever-faster rate. The discovery of the universe's accelerating expansion earned three physicists a Nobel prize last year, but no one knows its source. "What's causing the acceleration?"
Dark matter is slowly running out of places to hide. Two new looks at the gamma-ray sky suggest that if the mysterious matter is a particle, it is heavier than 40 gigaelectronvolts, about 44 times the mass of a proton. That contradicts hints from three experiments on Earth that pointed to a lightweight dark matter particle weighing just a quarter as much, although some researchers say such featherweights are still in the running. Dark matter particles may be heavyweights after all - space - 29 November 2011
Largest dark matter map holds clues to dark energy - space - 11 January 2012 We may not know what dark matter is, but we can still put it to work. The largest map of dark matter ever made (pictured) is one of several new ones that will help to nail the properties of the equally mysterious dark energy, which is thought to drive the universe's accelerating expansion. A group led by Catherine Heymans of the University of Edinburgh, UK, and Ludo Van Waerbeke of the University of British Columbia, Vancouver, Canada, presented the huge map at the American Astronomical Society (AAS) meeting in Austin, Texas, this week. Dark matter makes up 83 per cent of the universe's matter, but is invisible, so its presence must be inferred from its gravitational influence. This works because clumps of dark matter distort the space-time around them. Light from distant galaxies passing through those regions also gets warped, making the galaxies appear streaked and smeared in telescope images, a technique known as weak gravitational lensing.
Dark matter mysteries: a true game of shadows - 09 January 2012 Read full article Continue reading page |1|2|3 Far from shedding light on dark matter, our first experimental glimpses of the elusive stuff have only deepened its mystique
Two years ago several of my Sci Am colleagues and I had an intense email exchange over a period of weeks, trying to figure out what to make of a new paper by string theorist Erik Verlinde. I don’t think I’ve ever been so flummoxed by physicists’ reactions to a paper. Mathematically it could hardly have been simpler—the level of middle-school algebra for the most part. Logically and physically, it was a head-hurter. Is Dark Matter a Glimpse of a Deeper Level of Reality? | Critical Opalescence
Want to stay on top of all the space news? Follow @universetoday on Twitter Astronomers using NASA’s Fermi Gamma-Ray Space Telescope have been looking for evidence of suspected types of dark matter particles within faint dwarf galaxies near the Milky Way — relatively “boring” galaxies that have little activity but are known to contain large amounts of dark matter. Finding Out What Dark Matter Is – And Isn’t
The Whole Story on Dark Matter : Starts With A Bang “Science progresses best when observations force us to alter our preconceptions.” -Vera Rubin I want you to think about the Universe.
Biggest Map Yet of Universe's Invisible Dark Matter Unveiled AUSTIN, Texas — The hidden side of the universe is now a bit more illuminated thanks to the largest map yet of dark matter, the strange substance thought to inhabit much of space. Scientists have created the largest scale rendering of dark matter across the universe, revealing a picture of the invisible stuff thought to represent 98 percent of all matter in the universe. Dark matter has never been directly detected, but its presence is felt through its gravitational pull on normal matter. Scientists suspect dark matter is made of some exotic particle that doesn't interact with regular atoms.
Dark Matter Search Turns Up Empty
Want to stay on top of all the space news? Follow @universetoday on Twitter Arp 302 consists of a pair of very gas-rich spiral galaxies in their early stages of interaction. Newly Discovered Satellite Galaxies: Another Blow Against Dark Matter?
Closing in on Dark Matter: Another “Tentative” Step A galaxy cluster with the distribution of dark matter marked by purple overlay. Credit: NASA, ESA, E. Julio (JPL/LAM), P. Natarajan (Yale) and J-P.
THE skeleton of dark matter that undergirds the cosmic web of matter in the universe has been clearly detected for first time. We know that matter in the cosmos forms a web, with galaxies and clusters linked by filaments across mostly empty space. Filaments are made of normal matter and dark matter - the unseen stuff that makes up about 85 per cent of the universe's mass. Dark matter underpinnings of cosmic web found - space - 04 July 2012
Nearby dark-matter-free zone poses cosmic conundrum - space - 20 April 2012
Dark Matter Hits the Average Human Once a Minute?
Humble DNA could help decipher dark matter - physics-math - 02 July 2012
eso1217 - Serious Blow to Dark Matter Theories?
Blame dark matter underdog for mystery missing lithium - space - 23 February 2012
Could ‘Mirror Neutrons’ Account for Unobservable Dark Matter?
Earth has little to fear from a black hole attack - space - 30 March 2012
A Galactic Challenge: How Would You Teach Left from Right to an Alien Civilization? | Degrees of Freedom
How the Modern Physics was invented in the 17th century, part 1: The Needham Question | Guest Blog
How the Modern Physics was invented in the 17th century, part 3: Why Galileo didn’t discover universal gravitation? | Guest Blog
How the Modern Physics was invented in the 17th century, part 2: source of fundamental laws | Guest Blog
Plutonium signature captured after 50 years of trying - physics-math - 17 May 2012
Existence special: Cosmic mysteries, human questions
Does infinity exist?
Symmetry: A ‘Key to Nature’s Secrets’ by Steven Weinberg
In A Squeeze
Water Not So Squishy Under Pressure
Dancing Droplets Reveal Physics At Work
NASA satellite tastes atoms from beyond the solar system
ExoMars co-operation between Nasa and Esa near collapse
Project Icarus: Laying the Plans for Interstellar Travel - Ross Andersen - Technology
Controversy Surrounds Russia's Claim that Cosmic Rays Caused Mars Mission Failure
What If There Were No Gravity?
The Mystery of Gravity : The Astronomy Cafe : Dr. Sten Odenwald
Gravity Probe B: Testing Einstein's Universe
Alien Superfluids That Can Climb Upwards Detected at Core of Supernova Neutron Star (Today's Most Popular)
NASA finds space buckyballs in solid form
Astrophile: Glimpse elusive matter in shattering star - space - 13 January 2012
Hydrogen Takes A New Form
Cosmic race ends in a tie
New Data Find a Silver Lining of Cosmic Radiation
Radio Array Starts Work to Detect Whispers from Universe
Early Stars Created A Sight Yet Unseen
Habitable Zones in Other Galaxies
The 6 Most Likely Places to Find Alien Life | Search for Extraterrestrial Life in the Solar System
What Will We Find in Extraterrestrial Caves?
Alien Life May Not Be So Alien – If It Exists At All
How Do The Biggest Telescopes Work?
Is Space Digital?
How to Survive the End of the Universe | Cosmology
The Quantum Physics of Free Will
Teleportation record heralds secure global network - physics-math - 15 May 2012
Quantum Teleportation Leaps Forward