The supermassive black holes lurking at the centre of our - and every other - galaxy are growing surprisingly quickly, researchers say.
Black holes are initially formed by stars as they collapse, when lots of matter is compacted by gravity into a very small area.
The biggest black holes are found at the core of galaxies, where they are almost unimaginably huge - some contain 17 billion times the mass of our sun.
One black hole known to exist at the heart of the M104 galaxy (aka 'The Sombrero galaxy') has swallowed the equivalent of one sun every 20 years, according to Space.com.
It had been thought that these dark monsters were 'fed' by new matter at irregular intervals, when galaxies collide.
But now there is new evidence that instead most of these giant black holes are being fed continually be small meals of gas and other types of matter.
Simulations run by the University of Central Lancashire show that supermassive black holes, including those at the centre of the Milky Way, are more likely to grow in efficient, gradual terms and not in dramatic bursts.
They compared the mass of black holes in spiral galaxies compared to those in elliptical ones, and found there is no difference in how big they are - indicating the rate of growth is the same whether a galaxy has a violent history of dramatic collisions or not.
"These simulations show that it is no longer possible to argue that black holes in spiral galaxies do not grow efficiently," study lead author Victor Debattista said in a statement.
"Our simulations will allow us to refine our understanding of how black holes grew in different types of galaxies."
Hubble Captures View of 'Mystic Mountain'
Hubble's 20th anniversary image shows a mountain of dust and gas rising in the Carina Nebula. The top of a three-light-year tall pillar of cool hydrogen is being worn away by the radiation of nearby stars, while stars within the pillar unleash jets of gas that stream from the peaks. Credit: NASA, ESA, and M. Livio and the Hubble 20th Anniversary Team (STScI)
ACS Image of NGC 5866
Credit: NASA, ESA, and The Hubble Heritage Team (STScI/AURA) Acknowledgment: W. Keel (University of Alabama, Tuscaloosa)
Giant "Twisters" in the Lagoon Nebula
Credit: A. Caulet (ST-ECF, ESA) and NASA
The Spirograph Nebula (IC 418)
Credit: NASA and The Hubble Heritage Team (STScI/AURA) Acknowledgment: Dr. Raghvendra Sahai (JPL) and Dr. Arsen R. Hajian (USNO)
30 Doradus in Ultraviolet, Visible, and Red Light
Credit: NASA, ESA, F. Paresce (INAF-IASF, Bologna, Italy), R. O'Connell (University of Virginia, Charlottesville), and the Wide Field Camera 3 Science Oversight Committee
The Ant Nebula (Menzel 3): Fiery Lobes Protrude From Dying, Sun-like Star
Image Credit: NASA, ESA and The Hubble Heritage Team (STScI/AURA) Acknowledgment: R. Sahai (Jet Propulsion Lab) and B. Balick (University of Washington)
The Eskimo Nebula (NGC 2392)
Credit: NASA, Andrew Fruchter and the ERO Team [Sylvia Baggett (STScI), Richard Hook (ST-ECF), Zoltan Levay (STScI)]
Dying Star HD 44179, the "Red Rectangle," Sculpts Rungs of Gas and Dust
Credit: NASA; ESA; Hans Van Winckel (Catholic University of Leuven, Belgium); and Martin Cohen (University of California, Berkeley)
Galaxy Triplet Arp 274
Arp 274 is a trio of galaxies. They appear to be partially overlapping in this image, but may be located at different distances. Credit: NASA, ESA, M. Livio and the Hubble Heritage Team (STScI/AURA)
Cassiopeia A: Colorful, Shredded Remains of Old Supernova
This youngest-known supernova remnant in our galaxy lies 10,000 light years away in the constellation Cassiopeia. The light from this exploding star first reached Earth in the 1600s. Image Credit: NASA and The Hubble Heritage Team (STScI/AURA) Acknowledgment: R. Fesen (Dartmouth) and J. Morse (Univ. of Colorado)
Rainbow Image of the Egg Nebula
An onionskin-like structure of concentric dust shells surround a central, aging star. Twin beams of light radiate from the star and illuminate the usually invisible dust. Artificial colors show how light reflects off the particles and heads toward Earth. Credit: NASA and The Hubble Heritage Team (STScI/AURA) Acknowledgment: W. Sparks (STScI) and R. Sahai (JPL)
Jet in Carina: WFC3 UVIS Full Field
Credit: NASA, ESA, and the Hubble SM4 ERO Team
Jet in Carina
Credit: NASA, ESA, and the Hubble SM4 ERO Team
Starburst Galaxy M82
Plumes of glowing hydrogen blast from the central nucleus of M82. The pale, star-like objects are clusters of tens to hundreds of thousands of stars. Credit: NASA, ESA, and The Hubble Heritage Team (STScI/AURA) Acknowledgment: J. Gallagher (University of Wisconsin), M. Mountain (STScI), and P. Puxley (National Science Foundation)
Picture Album: Hubble's Black and White View of the Universe
Credit: NASA, ESA, and The Hubble Heritage Team (STScI/AURA) Acknowledgment: A. Nota (STScI/ESA)
The Eagle Has Risen: Stellar Spire in the Eagle Nebula
A billowing tower of gas and dust rises from the stellar nursery known as the Eagle Nebula. This small piece of the Eagle Nebula is 57 trillion miles long (91.7 trillion km). Credit: NASA, ESA, and The Hubble Heritage Team (STScI/AURA)
Ring of Hot Blue Stars Pinwheels Around Yellow Nucleus of Hoag's Object Galaxy
Image Credit: NASA and The Hubble Heritage Team (STScI/AURA) Acknowledgment: Ray A. Lucas (STScI/AURA)
Nucleus of Galaxy Centaurus A
Credit: E.J. Schreier (STScI), and NASA
Saturn's Rings in Ultraviolet Light
Credit: NASA and E. Karkoschka (University of Arizona)
HST ACS/WFC Image of NGC 3021
Credit: NASA, ESA, and A. Riess (STScI/JHU)
NASA's Great Observatories Examine the Galactic Center Region
Credit: NASA, ESA, SSC, CXC, and STScI
Interacting Spiral Galaxies NGC 2207 and IC 2163
Image Credit: NASA, ESA, and The Hubble Heritage Team (STScI)
Combined X-Ray and Optical Images of the Crab Nebula
Credits for X-ray Image: NASA/CXC/ASU/J. Hester et al. Credits for Optical Image: NASA/HST/ASU/J. Hester et al.
Hubble's Sharpest View of the Orion Nebula
Thousands of stars are forming in the cloud of gas and dust known as the Orion nebula. More than 3,000 stars of various sizes appear in this image. Some of them have never been seen in visible light. Credit: NASA,ESA, M. Robberto (Space Telescope Science Institute/ESA) and the Hubble Space Telescope Orion Treasury Project Team
Star-Forming Region S106
Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)
A String of 'Cosmic Pearls' Surrounds an Exploding Star
Credit: NASA, ESA, P. Challis and R. Kirshner (Harvard-Smithsonian Center for Astrophysics)
A Perfect Storm of Turbulent Gases in the Omega/Swan Nebula (M17)
Credit: NASA, ESA and J. Hester (ASU)
Three Moons Cast Shadows on Jupiter
Credit: NASA, ESA, and E. Karkoschka (University of Arizona)
The Helix Nebula: a Gaseous Envelope Expelled By a Dying Star
Credit: NASA, ESA, C.R. O'Dell (Vanderbilt University), M. Meixner and P. McCullough (STScI)
"Light Echo" Illuminates Dust Around Supergiant Star V838 Monocerotis (V838 Mon)
Credit: NASA and The Hubble Heritage Team (AURA/STScI)
The Cat's Eye Nebula: Dying Star Creates Fantasy-like Sculpture of Gas and Dust
The Cat's Eye Nebula, one of the first planetary nebulae discovered, also has one of the most complex forms known to this kind of nebula. Eleven rings, or shells, of gas make up the Cat's Eye. Credit: NASA, ESA, HEIC, and The Hubble Heritage Team (STScI/AURA) Acknowledgment: R. Corradi (Isaac Newton Group of Telescopes, Spain) and Z. Tsvetanov (NASA)
Optical and X-ray Composite Image of SNR 0509-67.5
Science Credit: NASA, ESA, and B. Schaefer and A. Pagnotta (Louisiana State University, Baton Rouge) Image Credit: NASA, ESA, CXC, SAO, the Hubble Heritage Team (STScI/AURA), and J. Hughes (Rutgers University)
Spiral Galaxy M74
Bright knots of glowing gas light up the arms of spiral galaxy M74, indicating a rich environment of star formation. Messier 74, also called NGC 628, is slightly smaller than our Milky Way. Credit: NASA, ESA, and the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration Acknowledgment: R. Chandar (University of Toledo) and J. Miller (University of Michigan)
"X" Structure at Core of Whirlpool Galaxy (M51)
Credit: H. Ford (JHU/STScI), the Faint Object Spectrograph IDT, and NASA
Starburst Cluster Shows Celestial Fireworks
Credit: NASA, ESA, R. O'Connell (University of Virginia), F. Paresce (National Institute for Astrophysics, Bologna, Italy), E. Young (Universities Space Research Association/Ames Research Center), the WFC3 Science Oversight Committee, and the Hubble Heritage Team (STScI/AURA)
A Giant Hubble Mosaic of the Crab Nebula
The Crab Nebula is a supernova remnant, all that remains of a tremendous stellar explosion. Observers in China and Japan recorded the supernova nearly 1,000 years ago, in 1054. Credit: NASA, ESA, J. Hester and A. Loll (Arizona State University)
The Majestic Sombrero Galaxy (M104)
A brilliant white core is encircled by thick dust lanes in this spiral galaxy, seen edge-on. The galaxy is 50,000 light-years across and 28 million light years from Earth. Credit: NASA and The Hubble Heritage Team (STScI/AURA)
Gas Pillars in the Eagle Nebula (M16): Pillars of Creation in a Star-Forming Region
Credit: NASA, ESA, STScI, J. Hester and P. Scowen (Arizona State University)
A Galactic Spectacle
Credit: NASA, ESA, SAO, CXC, JPL-Caltech, and STScI Acknowledgment: J. DePasquale (Harvard-Smithsonian CfA), and B. Whitmore (STScI)
Saturn's Double Light Show
Credit: NASA, ESA, and Jonathan Nichols (University of Leicester)