The Universe is full of massive galaxies like ours, but astronomers don’t fully understand how they grew and evolved. They know that the first galaxies formed at least as early as 670 million years after the Big Bang. They know that mergers play a role in the growth of galaxies. Astronomers also know that supermassive black holes are involved in the growth of galaxies, but they don’t know precisely how.
A new Hubble survey of galaxies should help astronomers figure some of this out.
A planetary nebula is one of the most beautiful objects in the universe. Formed from the decaying remnants of a mid-sized star like a sun, no two are alike. Cosmically ephemeral, they last for only about 10,000 years – a blink of a cosmic eye. And yet they are vitally important, as their processed elements spread and intermingle with the interstellar medium in preparation for forming a new generation of stars. So studying them is important for understanding stellar evolution. But unlike their stellar brethren, since no two are alike, it’s hard to efficiently pick them out of astronomical deep-sky surveys. Thankfully, a research team has recently developed a method for doing just that, and their work could open up the door to fully understanding the great circle of stellar life.
Brace yourselves: winter is coming. And by winter I mean the slow heat-death of the Universe, and by brace yourselves I mean don’t get terribly concerned because the process will take a very, very, very long time. (But still, it’s coming.)
Based on findings from the Galaxy and Mass Assembly (GAMA) project, which used seven of the world’s most powerful telescopes to observe the sky in a wide array of electromagnetic wavelengths, the energy output of the nearby Universe (currently estimated to be ~13.82 billion years old) is currently half of what it was “only” 2 billion years ago — and it’s still decreasing.
“The Universe has basically plonked itself down on the sofa, pulled up a blanket and is about to nod off for an eternal doze,” said Professor Simon Driver from the International Centre for Radio Astronomy Research (ICRAR) in Western Australia, head of the nearly 100-member international research team.
As part of the GAMA survey 200,000 galaxies were observed in 21 different wavelengths, from ultraviolet to far-infrared, from both the ground and in space. It’s the largest multi-wavelength galaxy survey ever made.
Of course this is something scientists have known about for decades but what the survey shows is that the reduction in output is occurring across a wide range of wavelengths. The cooling is, on the whole, epidemic.
Watch a video below showing a fly-through 3D simulation of the GAMA survey:
“Just as we become less active in our old age, the same is happening with the Universe, and it’s well past its prime,” says Dr. Luke Davies, a member of the ICRAR research team, in the video.
But, unlike living carbon-based bags of mostly water like us, the Universe won’t ever actually die. And for a long time still galaxies will evolve, stars and planets will form, and life – wherever it may be found – will go on. But around it all the trend will be an inevitable dissipation of energy.
“It will just grow old forever, slowly converting less and less mass into energy as billions of years pass by,” Davies says, “until eventually it will become a cold, dark, and desolate place where all of the lights go out.”
Our own Solar System will be a quite different place by then, the Sun having cast off its outer layers – roasting Earth and the inner planets in the process – and spending its permanent retirement cooling off as a white dwarf. What will remain of Earthly organisms by then, including us? Will we have spread throughout the galaxy, bringing our planet’s evolutionary heritage with us to thrive elsewhere? Or will our cradle also be our grave? That’s entirely up to us. But one thing is certain: the Universe isn’t waiting around for us to decide what to do.
The findings were presented by Professor Driver on Aug. 10, 2015, at the IAU XXIX General Assembly in Honolulu, and have been submitted for publication in the Monthly Notices of the Royal Astronomical Society.
“We found that Americans are consistently more likely to say that the U.S. spends too much on space exploration than too little. At no time has more than 20% of the public said that the U.S. spends too little on space exploration,” Pew wrote in the article of the survey, which has been running for about 40 years.
Not everyone agrees with that interpretation of those numbers. In a personal website blog post published in 2013 (after the last GSS came out) NASA employee Dennis Boccippio said that financial support for space exploration has never been higher.
The blog post, which referred to preliminary data from the 2012 survey, showed “an overall higher favorability rating” that was stronger than any GSS survey or at points cited before then from the National Air and Space Museum’s Roger Launius. In particular, look at this graph that Boccippio published on his blog.
“The GSS surveys consistently show a slightly lower favorability rating for the survey question variant ‘space exploration program’ versus ‘space exploration’ – but it’s very small. This may be one way to measure the difference between supporting the concept of exploration and supporting government programs,” Boccippio said in an e-mail to Universe Today. Boccippio is NASA’s manager of the center of strategic development at the Marshall Space Flight Center, but said he wrote the blog post as a private citizen.
“The Pew research article seems fairly written, you’ve seen the graphic on my blog, so it’s a matter of interpretation. The fact that a large (30-40%) number of respondents respond ‘we’re spending too much’, and that the strong advocate/proponent population is small (10-20%) isn’t really news, this has been consistent for decades, and one could as easily state from the same data ‘more than 50% of Americans have consistently said we’re spending the right amount on it.”
Boccippio added that what really interested him was two trends in the data: how supporters have gone up in the last two GSS surveys, and declines in people saying there was too much spending in the space program since 1992 (an era where the Hubble Space Telescope’s deformed mirror was high in public consciousness, along with Congressional debates about whether to build the International Space Station, he said.)
After an inquiry from Universe Today, Pew said part of the different interpretations could depend on “data analysis and weighting variations”, and added they made adjustments in the blog post to reflect those interpretations.
“We relied on the Roper Center calculations of the GSS data, the blogger you cite used preliminary data … At the same time, the general point we made still holds. At no time in GSS surveying has the support for more spending topped the figure of those saying there should be reductions in spending,” said Lee Rainie, the director of Pew’s Research Center’s Internet & American Life Project, in an e-mail.
“You make an interesting observation about the recent upward tick in the number of people who say we are spending too little on space exploration,” he added. “It was also interesting to us that over time these numbers reflect relatively less support for space exploration than for several other possible government priorities.” (Those other priorities, the blog post says, are education, health and alternative energy sources.)
Rainie also clarified that the space colonization survey did not necessarily ask respondents who would pay for it. “Our poll with the Smithsonian Magazine did not mention NASA in our question regarding long-term colonies on other planets, nor did our question suggest in any way who might perform planetary colonization,” he said.
“It’s likely the case that respondents may have had several ideas in mind when they answered the question: NASA, a private entity, an international group, or some combination of them. Our point in mentioning this was that Americans seem expectant and hopeful about further space exploration.”
What do you make of the numbers? Again, you can view the two posts here and here.