Large Magellanic Cloud on collision course with Milky Way — in 2.5 billion years
, January 3, 2019
As if battered post-Christmas finances, a looming disorderly Brexit and the prospect of a fresh nuclear arms race were not enough to dampen spirits, astronomers have declared that a nearby galaxy will slam into the Milky Way and could knock our solar system far into the cosmic void.
The unfortunate discovery was made after scientists ran computer simulations on the movement of the Large Magellanic Cloud (LMC), one of the many satellite galaxies that orbits the Milky Way. Rather than circling at a safe distance, or breaking free of the Milky Way’s gravitational pull, the researchers found the LMC is destined to clatter into the galaxy we call home.
At the moment, the LMC is estimated to be about 163,000 light years from the Milky Way and speeding away at 250 miles per second. But simulations by astrophysicists at Durham University show that the LMC will eventually slow down and turn back towards us, ultimately smashing into the Milky Way in about 2.5 billion years’ time. [Continue reading…]
The sugar that makes up DNA could be made in space
, December 22, 2018
Parts of DNA can form in space.
For the first time, scientists have made 2-deoxyribose, the sugar that makes up the backbone of DNA, under cosmic conditions in the lab by blasting ice with radiation. The result, reported December 18 in Nature Communications, suggests that there are several ways for prebiotic chemistry to take place in space, and supports the idea that the stuff of life could have been delivered to Earth from elsewhere.
“It tells us that this process happens everywhere, at least in our galaxy,” says astrochemist Michel Nuevo of NASA’s Ames Research Center in Moffett Field, Calif.
Nuevo and his colleagues cooled ices of frozen water and methanol to about –260° Celsius inside a vacuum chamber and blasted the ice with ultraviolet light, mimicking the conditions found in interstellar clouds. Warming the irradiated ices simulated what happens when a young star is born. After analyzing the ice’s contents, the team identified 2-deoxyribose, as well as several other kinds of sugars made in similar experiments in the past (SN: 4/30/16, p. 18). [Continue reading…]
After 41 years, Voyager 2 spacecraft enters interstellar space
, December 14, 2018
Voyager 2 has entered interstellar space. The spacecraft slipped out of the huge bubble of particles that encircles the solar system on November 5, becoming the second ever human-made craft to cross the heliosphere, or the boundary between the sun and the stars.
Coming in second place is no mean achievement. Voyager 1 became the first spacecraft to exit the solar system in 2012. But that craft’s plasma instrument stopped working in 1980, leaving scientists without a direct view of the solar wind, hot charged particles constantly streaming from the sun (SN Online: 9/12/13). Voyager 2’s plasma sensors are still working, providing unprecedented views of the space between stars.
“We’ve been waiting with bated breath for the last couple of months for us to be able to see this,” NASA solar physicist Nicola Fox said at a Dec. 10 news conference at the American Geophysical Union meeting in Washington, D.C. [Continue reading…]
Ice confirmed at the Moon’s poles
, August 21, 2018
For the first time, scientists have found what they say is definitive evidence of water ice on the surface of the moon.
The discovery suggests that future lunar expeditions might have a readily available source of water that would make it easier “to explore and even stay on the moon,” officials at NASA’s Jet Propulsion Laboratory said in a statement Tuesday about the discovery.
The ice was detected at the darkest, coldest regions of the moon’s north and south poles. It exists in sparse patches in the north and is concentrated in permanently shadowed craters in the south, where temperatures never climb above minus 250 degrees Fahrenheit.
Previous research had shown the existence of water deep beneath the lunar surface. There was also tentative evidence of water ice on the surface at the lunar south pole, but no proof until now. [Continue reading…]
A watery lake is detected on Mars, raising the potential for alien life
, July 25, 2018
For the first time, scientists have found a large, watery lake beneath an ice cap on Mars. Because water is essential to life, the discovery offers an exciting new place to search for life forms beyond Earth.
Italian scientists working on the European Space Agency’s Mars Express mission announced on Wednesday that a 12-mile wide underground liquid pool — not just the momentary damp spots seen in the past — had been detected by radar measurements near the Martian south pole.
“Water is there,” Enrico Flamini, the former chief scientist of the Italian Space Agency who oversaw the research, said during a news conference.
“It is liquid, and it’s salty, and it’s in contact with rocks,” he added. “There are all the ingredients for thinking that life can be there, or can be maintained there if life once existed on Mars.”
The body of water appears similar to underground lakes found on Earth in Greenland and Antarctica. On Earth, microbial life persists down in the dark, frigid waters of one such lake. The ice on Mars would also shield the Martian lake from the damaging radiation that bombards the planet’s surface. [Continue reading…]
The ecosystem that controls a galaxy’s future — its circumgalactic medium — is coming into focus
, July 14, 2018
There’s more to a galaxy than meets the eye. Galaxies’ bright stars seem to spiral serenely against the dark backdrop of space. But a more careful look reveals a whole lot of mayhem.
“Galaxies are just like you and me,” Jessica Werk, an astronomer at the University of Washington in Seattle, said in January at a meeting of the American Astronomical Society. “They live their lives in a constant state of turmoil.”
Much of that turmoil takes place in a huge, complicated setting called the circumgalactic medium, or CGM. This vast, roiling cloud of dust and gas is a galaxy’s fuel source, waste dump and recycling center all in one. Astronomers think the answers to some of the most pressing galactic mysteries — how galaxies keep forming new stars for billions of years, why star formation abruptly stops — are hidden in a galaxy’s enveloping CGM.
“To understand the galaxies, you have to understand the ecosystem that they’re in,” says astronomer Molly Peeples of the Space Telescope Science Institute in Baltimore.
Yet this galactic atmosphere is so diffuse that it’s invisible — a liter of CGM contains just a single atom. It has taken almost 60 years and an upgrade to the Hubble Space Telescope just to begin probing distant CGMs and figuring out how their constant churning can make or break galaxies. [Continue reading…]
First sighting of a newborn planet
, July 2, 2018
It is a moment of birth that has previously proved elusive, but astronomers say they now have the first confirmed image of the formation of a planet.
The startling snapshot shows a bright blob – the nascent planet – travelling through the dust and gas surrounding a young star, known as PDS70, thought to be about 370 light years from Earth.
The black circle in the centre of the image, to the left of the planet, is a filter to block the light from the star, enabling other features of the system to be seen.
Captured by the Sphere instrument of the European Southern Observatory’s Very Large Telescope, the planet – a gas giant with a mass greater than Jupiter – is about as far from its star as Uranus is from our sun, with further analyses revealing that it appears to have a cloudy atmosphere and a surface temperature of 1000C. [Continue reading…]
Space is full of dirty, toxic grease, scientists reveal
, June 28, 2018
It looks cold, dark and empty, but astronomers have revealed that interstellar space is permeated with a fine mist of grease-like molecules.
The study provides the most precise estimate yet of the amount of “space grease” in the Milky Way, by recreating the carbon-based compounds in the laboratory. The Australian-Turkish team discovered more than expected: 10 billion trillion trillion tonnes of gloop, or enough for 40 trillion trillion trillion packs of butter.
Prof Tim Schmidt, a chemist at the University of New South Wales, Sydney and co-author of the study, said that the windscreen of a future spaceship travelling through interstellar space might be expected to get a sticky coating.
“Amongst other stuff it’ll run into is interstellar dust, which is partly grease, partly soot and partly silicates like sand,” he said, adding that the grease is swept away within our own solar system by the solar wind.
The findings bring scientists closer to figuring out the total amount of carbon in interstellar space, which fuels the formation of stars, planets and is essential for life. [Continue reading…]
The next big discovery in astronomy? Scientists probably found it years ago – but they don’t know it yet
, May 15, 2018
NASA/JPL-Caltech
By Eileen Meyer, University of Maryland, Baltimore County
Earlier this year, astronomers stumbled upon a fascinating finding: Thousands of black holes likely exist near the center of our galaxy.
The X-ray images that enabled this discovery weren’t from some state-of-the-art new telescope. Nor were they even recently taken – some of the data was collected nearly 20 years ago.
No, the researchers discovered the black holes by digging through old, long-archived data.
Discoveries like this will only become more common, as the era of “big data” changes how science is done. Astronomers are gathering an exponentially greater amount of data every day – so much that it will take years to uncover all the hidden signals buried in the archives.
The evolution of astronomy
Sixty years ago, the typical astronomer worked largely alone or in a small team. They likely had access to a respectably large ground-based optical telescope at their home institution.
Their observations were largely confined to optical wavelengths – more or less what the eye can see. That meant they missed signals from a host of astrophysical sources, which can emit non-visible radiation from very low-frequency radio all the way up to high-energy gamma rays. For the most part, if you wanted to do astronomy, you had to be an academic or eccentric rich person with access to a good telescope.
Old data was stored in the form of photographic plates or published catalogs. But accessing archives from other observatories could be difficult – and it was virtually impossible for amateur astronomers.
Today, there are observatories that cover the entire electromagnetic spectrum. No longer operated by single institutions, these state-of-the-art observatories are usually launched by space agencies and are often joint efforts involving many countries.
With the coming of the digital age, almost all data are publicly available shortly after they are obtained. This makes astronomy very democratic – anyone who wants to can reanalyze almost any data set that makes the news. (You too can look at the Chandra data that led to the discovery of thousands of black holes!)