In March of 2004, the European Space Agency’s Rosettaspacecraft blasted off from French Guiana aboard an Ariane 5 rocket. After ten years, by November of 2014, the spacecraft rendezvoused with its target – Comet 67P/Churyumov-Gerasimenko (67P/C-G). Over the more than two years that followed, the spacecraft remained in orbit of this comet, gathering information on its surface, interior, and gas and dust environment.
And on September 30th, 2016, Rosetta came closer than ever to the surface of 67P/C-G and concluded its mission with a controlled impact onto the surface. Since that time, scientists have still been processing all the data the spacecraft collected during its mission. This included some awe-inspiring photographs of the comet’s surface that were obtained shortly after the spacecraft made its rendezvous with 67P/C-G.
Imagine, if you will, that the Universe was once a much dirtier place than it is today. Imagine also that what we see around us, a relatively clean and unobscured Universe, is the result of billions of years of stars behaving like giant celestial Roombas, cleaning up the space around them in preparation for our arrival. According to a set of recently published catalogues, which detail the latest findings from the ESA’s Herschel Space Observatory, this description is actually quite fitting.
These catalogues represents the work of an international team of over 100 astronomers who have spent the past seven years analyzing the infrared images taken by the Herschel Astrophysical Terahertz Large Area Survey (Herschel-ATLAS). Presented earlier this week at the National Astronomy Meeting in Nottingham, this catalogue revealed that 1 billion years after the Big Bang, the Universe looked much different than it does today.
In order to put this research into context, it is important to understand the important of infrared astronomy. Prior to the deployment of missions like Herschel (which was launched in 2009), astronomers were unable to see a good portion of the light emitted by stars and galaxies. With roughly half of this light being absorbed by interstellar dust grains, research into the birth and lives of galaxies was difficult.
But thanks to surveys like Herschel ATLAS – as well NASA’s Spitzer Space Telescope and the Wide-field Infrared Survey Explorer (WISE) – astronomers have been able to account for this missing energy. And what they have seen (especially from this latest survey) has been quite remarkable, presenting a Universe that is far denser than previously expected.
Professor Haley Gomez of Cardiff University presented this catalogue during the third day of the National Astronomy Meeting (which ran from June 27th to July 1st). As she told Universe Today via email:
“The Herschel survey is the largest one of the sky in these special infrared light. Because of this we see rare objects that we might not see in a smaller patch of sky, but also we now see hundreds of thousands of dusty galaxies, compared to the few hundred we saw in previous telescopes. So this is a massive improvement in terms of knowing what kinds of galaxies there are. Some of these are so covered in dust we might never had seen them using visible light telescopes. Because of the unprecedented large area we have with this Herschel survey, we see a huge variety in the type of objects too, from nearby dusty star forming clouds, to nearby dusty galaxies like Andromeda, to galaxies that shone their infrared light more than 12 billion years ago. We can also use this survey to understand the structure of galaxies in the universe – the so-called cosmic web in a way we’ve never been able to do in the far infrared.”
The images they showed gave all those present a glimpse of the unseen stars and galaxies that have existed over the last 12 billion years of cosmic history. In sum, over half-a-million far-infrared sources have been spotted by the Herschel-ATLAS survey. Many of these sources were galaxies that are nearby and similar to our own, and which are detectable using using conventional telescopes.
The others were much more distant, their light taking billions of years to reach us, and were obscured by concentrations of cosmic dust. The most distant of these galaxies were roughly 12 billion light-years away, which means that they appeared as they would have 12 billion years ago.
Ergo, astronomers now know that 12 billion years ago (i.e. shortly after the Big Bang)., stars and galaxies were much dustier than they are now. They further concluded that the evolution of our galaxies since shortly after the Big Bang has essentially been a major clean-up effort, as stars gradually absorbed the dust that obscured their light, thus making it the more “visible” place it is today.
“Gas and dust are the main components of stars: they collapse to form stars and they are ejected at the end of stars’ life. The interesting thing that has been discovered thanks to the Herschel data is that the two phenomena are not in equilibrium. We knew this was true 10 billion years ago, but we expected, according to the current models, that some equilibrium was reached at more recent times. Instead, the amount of dust in galaxies 5 billion years ago was much larger than the amount we see in galaxies today: this was unexpected.”
Until recently, such a survey would have been impossible due to the fact that many of these infrared sources would have been invisible to astronomers. The reason for this, which was revealed by the survey, was that these galaxies were so dusty that they would have been virtually impossible to detect with conventional optics. What’s more, their light would have been gravitationally magnified by intervening galaxies.
The huge size of the survey has also meant that changes that have occurred in galaxies – relatively recent in cosmic history – can be studied for the first time. For instance, the survey showed that even only one billion years in the past, a small fraction of the age of the universe, galaxies were forming stars at a faster rate and contained more dust than they do today.
Dr. Nathan Bourne – from the University of Edinburgh – is the lead author of another other paper describing the catalogues. As he told Universe Today via email:
“We can think of galaxies as big recycling machines. When they form, they accrete gas (mostly hydrogen and helium, with traces of lithium and a couple of other elements) from the universe around them, and they turn it into stars. As time goes on, the stars pump this gas back out into the galaxy, into the interstellar medium. Due to the nuclear processes within the stars, the gas is now enriched by heavy elements (what we call metals, though they include both metals and non-metals), and some of these form microscopic solid particles of dust, as a sort of by-product.
“But there are still stars forming, and the next generations of stars recycle this interstellar material, and now that it contains heavy elements and dust, things are a bit different, and planets can also form around the new stars, from accumulations of this heavy material. So, if you look at the big picture, when the first galaxies started forming within the first billion years after the Big Bang, they began using up the gas around them, and then while they are active they fill their interstellar medium up with gas and dust, but by the end of a galaxy’s lifecycle, it has used up all this gas and dust, and you could say that it has cleaned itself.”
The catalogues and maps of the hidden universe are a triumph for the Herschel team. Despite the fact that the last information obtained by the Herschel observatory was back in 2013, the maps and catalogues produced from its years of service have become vital to astronomers. In addition to showing the Universe’s hidden energy, they are also laying the groundwork for future research.
“Now we need to explain why there is dust where we did not expect to find it.” said Valiante. “And to explain this, we need to change our theories about how the Universe evolves. Our data poses a challenge we have accepted, but we haven’t overcome it yet!”
“[W]e understand a lot more about how galaxies evolve,” added Bourne, “about when most of the stars formed, what happens to the gas and dust as galaxies evolve, and how rapidly the star-forming activity in the Universe as a whole has faded in the latter half of the Universe’s history. It’s fair to say that this understanding comes from having a whole suite of different types of instruments studying different aspects of galaxies in complementary ways, but Herschel has certainly contributed a major part of that effort and will have a lasting legacy.”
Ensuring Herschel’s lasting legacy is one of the main aims of the Herschel Extragalactic Project (HELP) program, which is overseen by the EU Research Executive Agency. Other projects they oversee include the Herschel Multi-tiered Extragalactic Survey (HerMES), which also released survey data late last month. All of this has left a lasting mark on the field of astronomy, despite the fact that Herschel is no longer in operation. As Professor Gomez said of the Herschel Observatory’s enduring contributions:
“The Herschel Space Observatory stopped taking data in 2013, yet our understanding of the dusty universe is really only just starting with the release of large surveys and galaxy catalogues in recent months. Ultimately, once astronomers have gone through all the valuable data, Herschel will have provided a view of the infrared universe covering 1000 square degrees of the sky.”
The implications of these findings are also likely to have a far-reaching effect, ranging from cosmology and astronomy, to perhaps shedding some light on that tricky Fermi paradox. Could it be intelligent life that emerged billions of years ago didn’t venture to other star systems because they couldn’t see them? Just a thought…
Stunning high definition views of Earth’s auroras and dancing lights as seen from space like never before have just been released by NASA in the form of ultra-high definition videos (4K) captured from the International Space Station (ISS).
Whether seen from the Earth or space, auroras are endlessly fascinating and appreciated by everyone young and old and from all walks of life.
The spectacular video compilation, shown below, was created from time-lapses shot from ultra-high definition cameras mounted at several locations on the ISS.
It includes HD view of both the Aurora Borealis and Aurora Australis phenomena seen over the northern and southern hemispheres.
The video begins with an incredible time lapse sequence of an astronaut cranking open the covers off the domed cupola – everyone’s favorite locale. Along the way it also shows views taken from inside the cupola.
The video was produced by Harmonic exclusively for NASA TV UHD;
Video caption: Ultra-high definition (4K) time-lapses of both the Aurora Borealis and Aurora Australis phenomena shot from the International Space Station (ISS). Credit: NASA
The video segue ways into multi hued auroral views including Russian Soyuz and Progress capsules, the stations spinning solar panels, truss and robotic arm, flying over Europe, North America, Africa, the Middle East, star fields, the setting sun and moon, and much more.
Auroral phenomena occur when electrically charged electrons and protons in the Earth’s magnetic field collide with neutral atoms in the upper atmosphere.
“The dancing lights of the aurora provide a spectacular show for those on the ground, but also capture the imaginations of scientists who study the aurora and the complex processes that create them,” as described by NASA.
Here’s another musical version to enjoy:
The ISS orbits some 250 miles (400 kilometers) overhead with a multinational crew of six astronauts and cosmonauts living and working aboard.
The current Expedition 47 crew is comprised of Jeff Williams and Tim Kopra of NASA, Tim Peake of ESA (European Space Agency) and cosmonauts Yuri Malenchenko, Alexey Ovchinin and Oleg Skripochka of Roscosmos.
Some of the imagery was shot by recent prior space station crew members.
Here is a recent aurora image taken by flight engineer Tim Peake of ESA as the ISS passed through on Feb. 23, 2016.
“The @Space_Station just passed straight through a thick green fog of #aurora…eerie but very beautiful,” Peake wrote on social media.
The vehicle is in “good health” with the solar panels unfurled, generating power and on course for the 500 Million kilometer (300 million mile) journey to Mars.
“Acquisition of signal confirmed. We have a mission to Mars!” announced Mission Control from the European Space Agency.
The joint European/Russian ExoMars spacecraft successfully blasted off from the Baikonur Cosmodrome in Kazakhstan atop a Russian Proton-M rocket at 5:31:42 a.m. EDT (0931:42 GMT), Monday, March 14, with the goal of searching for possible signatures of life in the form of trace amounts of atmospheric methane on the Red Planet.
Video caption: Blastoff of Russian Proton rocket from the Baikonur Cosmodrome carrying ExoMars 2016 mission on March 14, 2016. Credit: Roscosmos
The first three stages of the 191-foot-tall (58-meter) Russian-built rocket fired as scheduled over the first ten minutes and lofted the 9,550-pound (4,332-kilogram) ExoMars to orbit.
Three more firings from the Breeze-M fourth stage quickly raised the probe into progressively higher temporary parking orbits around Earth.
But the science and engineering teams from the European Space Agency (ESA) and Roscosmos had to keep their fingers crossed and endure an agonizingly long wait of more than 10 hours before the fourth and final ignition of the Proton’s Breeze-M upper stage required to break the bonds of Earth.
The do or die last Breeze-M upper stage burn with ExoMars still attached was finally fired exactly as planned.
The probe was released at last from the Breeze at 20:13 GMT.
However, it took another long hour to corroborate the missions true success until the first acquisition of signal (AOS) from the spacecraft was received at ESA’s control centre in Darmstadt, Germany via the Malindi ground tracking station in Africa at 5:21:29 p.m. EST (21:29 GMT), confirming a fully successful launch with the spacecraft in good health.
It was propelled outwards to begin a seven-month-long journey to the Red Planet to the great relief of everyone involved from ESA, Roscosmos and other nations participating. An upper stage failure caused the total loss of Russia’s prior mission to Mars; Phobos-Grunt.
“Only the process of collaboration produces the best technical solutions for great research results. Roscosmos and ESA are confident of the mission’s success,” said Igor Komarov, General Director of the Roscosmos State Space Corporation, in a statement.
The ExoMars 2016 mission is comprised of a joined pair of European-built spacecraft consisting of the Trace Gas Orbiter (TGO) plus the Schiaparelli entry, descent and landing demonstrator module, built and funded by ESA.
“It’s been a long journey getting the first ExoMars mission to the launch pad, but thanks to the hard work and dedication of our international teams, a new era of Mars exploration is now within our reach,” says Johann-Dietrich Woerner, ESA’s Director General.
“I am grateful to our Russian partner, who have given this mission the best possible start today. Now we will explore Mars together.”
The cooperative mission includes significant participation from the Russian space agency Roscosmos who provided the Proton-M launcher, part of the science instrument package, the surface platform and ground station support.
The Trace Gas Orbiter (TGO) and Schiaparelli lander are speeding towards Mars joined together, on a collision course for the Red Planet. They will separate on October 16, 2016 at distance of 900,000 km from the planet, three days before arriving on October 19, 2016.
TGO will fire thrusters to alter course and enter an initial four-day elliptical orbit around the fourth planet from the sun ranging from 300 km at its perigee to 96 000 km at its apogee, or furthest point.
Over the next year, engineers will command TGO to fire thrusters and conduct a complex series of ‘aerobraking’ manoeuvres that will gradually lower the spacecraft to circular 400 km (250 mi) orbit above the surface.
The science mission to analyse for rare gases, including methane, in the thin Martian atmosphere at the nominal orbit is expected to begin in December 2017.
As TGO enters orbit, the Schiaparelli lander will smash into the atmosphere and begin a harrowing six minute descent to the surface.
The main purpose of Schiaparelli is to demonstrate key entry, descent, and landing technologies for the follow on 2nd ExoMars mission in 2018 that will land the first European rover on the Red Planet.
The battery powered lander is expected to operate for perhaps four and up to eight days until the battery is depleted.
It will conduct a number of environmental science studies such as “obtaining the first measurements of electric fields on the surface of Mars that, combined with measurements of the concentration of atmospheric dust, will provide new insights into the role of electric forces on dust lifting – the trigger for dust storms,” according to ESA.
Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.
Venus was once considered a twin to Earth, as it’s roughly the same size and is relatively close to our planet. But once astronomers looked at it seriously in the past half-century or so, a lot of contrasts emerged. The biggest one — Venus is actually a hothouse planet with a runaway greenhouse effect, making it inhospitable to life as we know it. Here are some more interesting facts about Venus.
1. Venus’ atmosphere killed spacecraft dead very quickly: You sure don’t want to hang around on Venus’ surface. The pressure there is so great that spacecraft need shielding to survive. The atmosphere is made up of carbon dioxide with bits of sulfuric acid, NASA says, which is deadly to humans. And if that’s not bad enough, the temperature at the surface is higher than 470 degrees Celsius (880 degrees Fahrenheit). The Soviet Venera probes that ventured to the surface decades ago didn’t last more than two hours.
2. But conditions are more temperate higher in the atmosphere: While you still couldn’t breathe the atmosphere high above Venus’ surface, at about 50 kilometers (31 miles) you’ll at least find the same pressure and atmosphere density as that of Earth. A very preliminary NASA study suggests that at some point, we could deploy airships for humans to explore Venus. And the backers suggest it may be more efficient to go to Venus than to Mars, with one large reason being that Venus is closer to Earth.
3. Venus is so bright it is sometimes mistaken for a UFO: The planet is completely socked in by cloud, which makes it extremely reflective to observers looking at the sky on Earth. Its brightness is between -3.8 and -4.8 magnitude, which makes it brighter than the stars in the sky. In fact, it’s so bright that you can see it go through phases in a telescope — and it can cast shadows! So that remarkable appearance can confuse people not familiar with Venus in the sky, leading to reports of airplanes or UFOs.
4. And those clouds mean you can’t see the surface: If you were to look at Venus with your eyes, you wouldn’t be able to see its surface. That’s because the clouds are so thick that they obscure what is below. NASA got around that problem when it sent the Magellan probe to Venus for exploration in the 1990s. The probe orbited the planet and got a complete surface picture using radar.
5. Venus has volcanoes and a fresh face: Venus has fresh lava flows on its surface, which implies that volcanoes erupted anywhere from the past few hundred years to the past three million years. What this means is there are few impact craters on the surface, likely because the lava flowed over them and filled them in. While scientists believe the volcanoes are responsible, the larger question is how frequently this occurs.
6. Venus has a bizarre rotation: Venus not only rotates backwards compared to the other planets, but it rotates very slowly. In fact, a day on Venus (243 days) lasts longer than it takes the planet to orbit around the Sun (225 days). Even more strangely, the rotation appears to be slowing down; Venus is turning 6.5 minutes more slowly in 2014 than in the early 1990s. One theory for the change could be the planet’s weather; its thick atmosphere may grind against the surface and slow down the rotation.
7. Venus has no moons or rings: The two planets closest to the Sun have no rings or moons, which puts Venus in the company of only one other world: Mercury. Every other planet in the Solar System has one or the other, or in many cases both! Why this is is a mystery to scientists, but they are doing as much comparison of different planets as possible to understand what’s going on.
8. Venus appears to be a spot where spacecraft go to extremes: We briefly mentioned the Venera probes that landed on the surface, but that’s not the only unusual spacecraft activity at Venus. In 2014, the European Space Agency put an orbiter — that’s right, a spacecraft not designed to survive the atmosphere — into the upper parts of Venus’ dense atmosphere. Venus Express did indeed survive the encounter (before it ran out of gas), with the goal of providing more information about how the atmosphere looks at high altitudes. This could help with landings in the future.
As you can see, Venus is an interesting, mysterious, and extremely hostile world. With such a corrosive atmosphere, such incredible heat, a volcanically-scarred surface, and thick clouds of toxic gas, one would have to be crazy to want to live there. And yet, there are some who believe Venus could be terraformed for human use, or at the very least explored using airships, in the coming generations.
But that’s the thing about interesting places. Initially, they draw their fair share of research and attention. But eventually, the dreamers and adventurers come.