Through an extraordinary chance alignment, the Hubble telescope has captured a view of a face-on spiral galaxy lying precisely in front of another larger spiral. The unique pair is called NGC 3314. This line-up provides astronomers with the rare chance to see the dark material within the foreground galaxy, seen only because it is silhouetted against the light from the object behind it. NGC 3314 lies about 140 million light-years from Earth in the direction of the southern hemisphere constellation Hydra.
This picture is one of many produced by the Hubble Heritage Program, created 1-1/2 years ago to publicly release some of the best celestial views taken by the telescope's visible-light camera. Now, the International Center of Photography in New York City has rewarded the program for its work with the annual Infinity Award for Applied Photography.
NASA/ESA and The Hubble Heritage Team (STScI/AURA)
An Undiscovered Galaxy Just Photobombed the Hubble Telescope
February 6, 2019 by Elizabeth Howell /
When NASA compares a scientific discovery to a game of "Where's Waldo?", you know something fun will be announced. It turns out the Hubble Space Telescope discovered a dwarf galaxy in our stellar neighborhood. The best thing about this find is it was completely accidental.
What the telescope was really doing was photographing a star cluster called NGC 6752, which is 13,000 light-years away — a respectable distance by cosmic standards. (A light-year is the distance light travels in a year; our own Milky Way galaxy is about 100,000 light-years across.)
So imagine astronomers' surprise when a "loner" galaxy popped up in the image. It was super-tiny and super-faint, but scrutiny showed that this tiny, 3,000-light-year-across galaxy was something like 30 million light-years away from us. That's about 12 times further than the Andromeda Galaxy, a bright object that northern hemisphere observers can see with the naked eye (no telescopes or binoculars needed).
Now that astronomers know where this galaxy is hiding, they promise us that it will teach us more about how galaxies change as they grow and age. In fact, this galaxy is almost as old as our universe itself, which is estimated at 13.7 billion years. "Because of its 13-billion-year-old age, and its isolation — which resulted in hardly any interaction with other galaxies — the dwarf is the astronomical equivalent of a living fossil from the early universe," NASA said in a statement.
When will the Milky Way and Andromeda galaxies collide?
By EarthSky in SPACE | February 8, 2019
The Andromeda galaxy is the nearest large spiral to our Milky Way. Astronomers have suspected for some time it will eventually collide with our Milky Way. Now – thanks to the Gaia satellite – they know more.
Boom! Future motions of the Milky Way and Andromeda galaxies show them on a collision course. Meanwhile, the 3rd major galaxy in our Local Group – the Triangulum galaxy – is likely to give the collision a wide berth. Image via ESA/Gaia/DPAC.
Astronomers have said for some time that the nearby Andromeda galaxy – also known as M31, nearest large spiral galaxy to our home Milky Way – will one day collide with the Milky Way. On February 7, 2019, the European Space Agency (ESA) provided an update on the newest insights about this impending collision, based on data from its Gaia satellite. Across the course of 2018, astronomers announced multiple, very interesting discoveries about our galaxy, based on Gaia’s second data release last April. Now Gaia has looked beyond the Milky Way, at the motions of stars within both the Andromeda galaxy and the Triangulum galaxy (aka M33), which is the third large galaxy in our Local Group. The data reveal some surprises about the Andromeda galaxy’s collision course with the Milky Way.
The first surprise is a new estimate for when the collision will occur. Astronomers thought it would happen some 3.9 billion years from now. But the astronomers who studied Gaia’s data said they now believe it’ll happen 600 million years later than previously estimated, perhaps 4.5 billion years from now. What’s more, they said, the Andromeda galaxy is:
"… likely to deliver more of a glancing blow to the Milky Way than a head-on collision."
These results were published February 7 in the peer-reviewed Astrophysical Journal. Astronomer Roeland van der Marel of the Space Telescope Science Institute in Baltimore – who led the study – commented:
"We needed to explore the galaxies’ motions in 3D to uncover how they have grown and evolved, and what creates and influences their features and behavior.
We were able to do this using the second package of high-quality data released by Gaia."
Gaia does what is called astrometry. Its job is to scan the sky repeatedly, observing each of its targeted billion-plus stars an average of 70 times over its five-year mission. Again and again and again, Gaia will acquire data points on the positions of stars in the Milky Way, and now in the Andromeda and Triangulum galaxies, too. We know that stars move through space. Gaia will tell us, exactly, how they moved during that five-year period.
It may not sound very dramatic. But it is. That much knowledge about star motions – actual data on the motions of more than a billion stars – is unprecedented in the history of astronomy. That is why there have been so many astounding discoveries from Gaia already.
Ultimately, Gaia’s data will be used to build the most precise 3D map of the stars in the nearby universe, ever. A statement from ESA explained:
"Previous studies of the Local Group have combined observations from telescopes including the NASA/ESA Hubble Space Telescope and the ground-based Very Long Baseline Array to figure out how the orbits of Andromeda and Triangulum have changed over time. The two disk-shaped spiral galaxies are located between 2.5 and 3 million light-years from us, and are close enough to one another that they may be interacting.
Two possibilities emerged: either Triangulum is on an incredibly long six-billion-year orbit around Andromeda but has already fallen into it in the past, or it is currently on its very first infall.
Each scenario reflects a different orbital path, and thus a different formation history and future for each galaxy."
That was where things stood until Gaia came along.
Mark Fardal, also of Space Telescope Science Institute, is second author on the new paper. He explained:
"We combed through the Gaia data to identify thousands of individual stars in both galaxies, and studied how these stars moved within their galactic homes.
While Gaia primarily aims to study the Milky Way, it’s powerful enough to spot especially massive and bright stars within nearby star-forming regions – even in galaxies beyond our own."
The stellar motions measured by Gaia not only reveal how each of the galaxies moves through space, but also how each rotates around its own spin axis, ESA said, adding:
"A century ago, when astronomers were first trying to understand the nature of galaxies, these spin measurements were much sought-after, but could not be successfully completed with the telescopes available at the time."
"It took an observatory as advanced as Gaia to finally do so. For the first time, we’ve measured how M31 and M33 rotate on the sky. Astronomers used to see galaxies as clustered worlds that couldn’t possibly be separate ‘islands’, but we now know otherwise.
It has taken 100 years and Gaia to finally measure the true, tiny, rotation rate of our nearest large galactic neighbor, M31. This will help us to understand more about the nature of galaxies."
Bottom line: An analysis of data from Gaia’s second data release revealed an longer-than-expected timeline for the impending collision between our Milky Way galaxy and the neighboring Andromeda galaxy. The data also show that the collision is likely to be a glancing blow, rather than the head-on crash that had been expected previously.
Sharpest-ever view of the Andromeda Galaxy, via the Hubble Space Telescope is at the URL below. On the right side, scroll down and click on "zoomable" feature to be mesmerized. You can zoom in and out. If you're bored and have some spare time, magnify and start counting stars.....:
casper: I'm back again!!! Maybe this time my computer won't die like it did the last time.
Apr 29, 2018 19:36:04 GMT -6
casper: Skywalker just fixed it. You know what that means. It's doomed.
Apr 29, 2018 19:36:53 GMT -6
skywalker: Very funny, ghost boy
Jun 3, 2018 14:58:58 GMT -6
lois: Casper he should come fix mine. Mine is doomed
Jun 26, 2018 21:54:27 GMT -6
spotless38: Iam back after a long break . What a couple of years I had . After what had happened I lost my brother and had to bury him and then I had caught that type A flue and I was a very sick puppy I also needed blood for the loss of it .
Jul 7, 2018 13:30:41 GMT -6
lois: Very Happy to see you Ron. Missed you. Glad you are doing better now. Sorry for your lost. I did not know your brother had passed. hugs lois
Jul 10, 2018 0:52:45 GMT -6
paulette: Ron - hope you've hit a quiet spot. Sorry for your loss.
Aug 3, 2018 10:49:30 GMT -6
lois: I picked up my phone a few days ago and I looked at the name of the caller. Boy was I surprise. It has been a couple of years. So good to hear your voice Ron. Hope you make it a habit again. love and hugs .
Aug 15, 2018 23:21:38 GMT -6
leia77: Spotless, I am glad that you are feeling better and welcome back! I too am back from a long time away...
Aug 31, 2018 2:08:32 GMT -6
jcurio: I am much relieved to see that you have been on here, Spotless! I hope that things are going much better for you now
Sept 19, 2018 16:46:42 GMT -6
jcurio: And Lois, And Lorelei!
Sept 19, 2018 16:47:07 GMT -6
casper: And Meeeeeee!!
Oct 16, 2018 18:41:31 GMT -6
lois: Sorry guys I cannot see the print. On is tiny hand computer
Oct 21, 2018 20:42:09 GMT -6
lois: Casper your page stops at page five in 2016
Nov 15, 2018 23:54:01 GMT -6
lois: How did your Halloween night go this year?
Nov 15, 2018 23:54:58 GMT -6
skywalker: He posted on the Halloween thread this year.
Nov 25, 2018 18:33:36 GMT -6
lois: Oh ok Sky I will check it out. Thanks.
Dec 21, 2018 21:45:31 GMT -6
lois: What topic was it under.
Dec 21, 2018 21:51:07 GMT -6