Why is the universe so homogenous? It should be a lot more clumpy.
Right after the Big Bang, the universe was still quite small and all the matter was compressed in this small volume. So gravity should have played a big role, causing all the matter to clump together with large areas of empty space in between.
Decades ago, some theorists developed the “inflation” theory to explain this fact. They said that right after the big bang, the universe expanded super incredibly fast. So fast that gravity didn’t have time to clump the matter together. This is why matter is spread so evenly, like a thin layer of peanut butter over a slice of bread, throughout the visible universe.
Lots of scientists didn’t believe it. I was among them. This didn’t make any sense because the expansion rate would be so fast, in a way, faster than the speed of light. Couldn’t happen.
Well, now we have physical proof that inflation really did happen.
This is really amazing. I’m glad I was wrong — it is so much more interesting this way!
A piece of Mars: Now here’s something that, as far as I know, can safely be labeled as “uniquely martian”. These dunes (or maybe they’re ripples) are ~25 m wide, and have formed from winds blowing from the upper left. Their upwind sides are smoothed by constant erosion from incident sand-laden winds, but their downwind sides are as bumpy as the surrounding surface. What makes this bumpy texture? (ESP_035305_1740, NASA/JPL/Univ. of Arizona)
Source: SETI Institute Press-release
MOUNTAIN VIEW, CA – For the first time, an Earth-sized planet has been found in the habitable zone of its star. This discovery not only proves the existence of worlds that might be similar to our own, but will undoubtedly shape future investigations of exoplanets that could have terrestrial surface environments.
A piece of Mars: This 521×391 m (1709×1283 ft) scene shows a rocky plain with many small impact craters (the bigger ones are ~45 m, or 148 ft across). Dark rippled sand fills the floors of the craters. Why? Once it blows in, it’s hard for the sand to get out. It gets caught in the nooks and crannies of the terrain. The same way it gets caught in your bathing suit and towel at the beach. (ESP_035164_1655, NASA/JPL/Univ. of Arizona)
Following our very successful first light observing runs in late 2013, the first publication based on Gemini Planet Imager observations is now complete! It has been accepted for publication in the Proceedings of the National Academy of Sciencesas part of a special issue on exoplanets, and is now available on Astro-ph. We report in this publication the performance of the Gemini Planet Imager based on the first light tests. The first scientific result demonstrates that right from the start, GPI has been performing well enough to yield new insights into exoplanets: Our astrometric observations from November 2013 gave us important new information on the orbit of the planet Beta Pictoris b.
A piece of Mars: Mars can be a strange place. This is actually a sand dune on Mars not far from the north pole. Here it’s imaged in the springtime when the dunes are still covered in bright CO2 frost, which is in turn overlain by yellowish dust that has fallen out of the atmosphere. The dark patch is a spot where the sunlight has penetrated the ice cover enough to allow some defrosting to begin — the dark line in the middle is close to the true color of ice-free sand. (HiRISE ESP_025126_2640, NASA/JPL/Univ. of Arizona)
Some may say that our universe is full of beauty, others argue that it is our solar system that surprises us the most, but ultimately I will say that it is the world of small solar system bodies which is strikingly full of diversity. Today’s announcement of the discovery of rings around the Centaur Chariklo by an international team of astronomers is a vivid proof that small solar system bodies have not yet revealed all their secrets.
A piece of Mars: Looks like a millipede, doesn’t it? It’s something much larger and much less poisonous. It’s an ancient dune (or maybe a ripple) on Mars, that once stretched ~285 m (935 ft) from lower left to middle right. Since then it’s been nearly rewritten twice. The first time, a different wind direction made smaller ripples (the millipede’s “feet”) that nearly erased the original shape. The second time, a cluster of craters formed, punching holes in the millipede. Maybe it was martian pest control. (HiIRSE ESP_034942_1615, NASA/JPL/Univ. of Arizona).
Jon Richards, The SETI Institute
The ICE spacecraft (see below) has recently approached Earth close enough to be detectable at the Allen Telescope Array (ATA). We have successfully detected the ICE spacecraft carrier signal using the SonATA (SETI on the ATA) signal detection equipment and will share the details here.
The technical community has been all abuzz about the return of the ICE spacecraft, formerly named the International Earth-Sun Explorer-3 (ISEE-3). It was launched in 1978 to study Earth’s magnetosphere and its interaction with the solar wind. The ICE spacecraft has been far away and out of contact for a long time and it is now quickly approaching earth once again. NASA has said it no longer has the equipment to communicate with the spacecraft. Radio enthusiasts around the world are trying to figure out a way to contact it and tell it to start dumping any data it may have gathered. The Bochum Observatory in Germany has been able to detect the ICE spacecraft with their 20 meter dish. Others are sure to follow.
Why We Observe Spacecraft
The Center for SETI Research at The SETI Institute operates a SETI signal detection program using the Allen Telescope Array located at the Hat Creek Radio Observatory, near Lassen Volcanic National Park in Northern California. For 12 hours every day, various stars, and now exoplanets discovered by the Kepler Mission and groundbased telescopes, are observed in an effort to detect any radio signal between 1 GHz and 10 GHz that may be from an extraterrestrial technological civilization.
On a regular basis we validate our system by pointing the 42 dishes of our telescope towards a known spacecraft to test if the system automatically detects a signal. If the signal is detected then we know the system is functioning properly. We like to observe a spacecraft that has weak signals and we commonly use Voyager1 which is very weak. Recently we have added the ICE spacecraft to the list of spacecraft we observe.
On March 10, 2014 we pointed towards the ICE spacecraft, tuned to its carrier signal frequency of 2217.5 MHz, and let the system do its thing. The ICE spacecraft signal was immediately detected. It was very weak, but strong enough for our SETI detector to recognize easily.
Frequency: 2217.519941667 MHz Drift Rate: -0.17 Hz/sec Signal width: 5.56 Hz
The system creates these images called “waterfall” plots with time on the y axis, frequency on the x axis. This representation allows us to readily see signals as lines or other shapes depending on the characteristics of the signal. You can see the ICE spacecraft signal as a fuzzy line, easier to see if you squint. The fuzziness may be evidence of oscillator degradation or of possible data transmission. The displacement away from 2217.5 MHz is the result of a Doppler shift due to the motion of the spacecraft relative to the array. The slope of the detected signal is a ‘Doppler drift’ due to relative acceleration between the spacecraft and Earth, as our planet rotates.
On March 14, 2014 we were able to detect the ICE spacecraft again
Frequency: 2217.520738889 MHz Drift Rate: -0.09 Hz/sec Signal width: 5.56 Hz
We will be using the detection of the ICE spacecraft as a system test for at least the next year, or until it becomes too weak for us to detect.
The ICE spacecraft is now just over 0.3 AU from Earth (about 45 million km). It is approaching Earth and will be closest on August 09, 2014. At closest approach the signal should be 10,000 times stronger than it is now.
Here is an zoom-in of the closest approach, this time with distance in km.
Keep tabs on our SETI observing at the ATA http://setiquest.info
Learn more about our signal detection system called SonATA (SETI on the ATA)
Learn more about The SETI Institute
NASA ICE mission info at http://science.nasa.gov/missions/isee/
The ICE spacecraft detected by the The Bochum Observatory in Germany.
- Follow Jon Richards on twitter at https://twitter.com/jrseti
A piece of Mars: Bet you didn’t know there were ribbons on Mars. Long, sweeping, velvety lines, delicately frayed at the ends. These are actually ancient ripples, formed by a wind blowing from right to left. Stripes on the ripples and on the ground between them show the ancient ripple interiors, exposed by erosion. The long ripple in left center is 175 m (574 ft) long. (HiRISE ESP_016136_1525, NASA/JPL/Univ. of Arizona)