Related Experiment Video
Updated: Jun 24, 2026
08:49
Self-Assembly of Microtubule Tactoids
Published on: June 23, 2022
Early assembly of the most massive galaxies
Chris A Collins1, John P Stott, Matt Hilton
1Astrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Egerton Wharf, Birkenhead, CH41 1LD, UK. cac@astro.livjm.ac.uk
Nature
|April 3, 2009
Summary
Brightest cluster galaxies were almost fully assembled over 90% of their stellar mass just 4-5 billion years after the Big Bang. This finding challenges galaxy formation models, suggesting rapid early growth rather than prolonged hierarchical assembly.
Area of Science:
- Astronomy and Astrophysics
- Cosmology
Background:
- Galaxies are believed to form from early Universe density fluctuations, growing through star formation and mergers.
- The timing of galaxy assembly, particularly for massive galaxies, remains a subject of debate in astrophysics.
Purpose of the Study:
- To investigate the assembly timeline of brightest cluster galaxies (BCGs).
- To compare observational data of BCG stellar mass with predictions from current galaxy formation models.
Main Methods:
- Analysis of stellar masses of BCGs approximately 9 billion years ago.
- Comparison of these masses with their present-day stellar masses.
Main Results:
- BCGs had already reached over 90% of their final stellar mass 4-5 billion years after the Big Bang.
- Observed stellar masses at this early epoch significantly differ from predictions of recent galaxy formation models.
Conclusions:
- BCGs experience a rapid growth phase early in the Universe.
- Current galaxy formation models may need revision to account for early, rapid assembly of massive galaxies.
Related Concept Videos
02:50Spindle Assembly
Spindle assembly occurs through three, often coexisting, pathways – the centrosome-mediated pathway, the chromatin-mediated pathway, and the microtubule-mediated pathway – collectively contributing to form a robust spindle apparatus.
In most cells, centrosomes are the primary microtubule nucleation centers. In the centrosome-mediated pathway, the G2-prophase transition triggers centrosome maturation and increased microtubule nucleation. Progressive nucleation results in a microtubule array...
In most cells, centrosomes are the primary microtubule nucleation centers. In the centrosome-mediated pathway, the G2-prophase transition triggers centrosome maturation and increased microtubule nucleation. Progressive nucleation results in a microtubule array...
02:50Spindle Assembly
Spindle assembly occurs through three, often coexisting, pathways – the centrosome-mediated pathway, the chromatin-mediated pathway, and the microtubule-mediated pathway – collectively contributing to form a robust spindle apparatus.
In most cells, centrosomes are the primary microtubule nucleation centers. In the centrosome-mediated pathway, the G2-prophase transition triggers centrosome maturation and increased microtubule nucleation. Progressive nucleation results in a microtubule array...
In most cells, centrosomes are the primary microtubule nucleation centers. In the centrosome-mediated pathway, the G2-prophase transition triggers centrosome maturation and increased microtubule nucleation. Progressive nucleation results in a microtubule array...
01:10Detection of Black Holes
Although black holes were theoretically postulated in the 1920s, they remained outside the domain of observational astronomy until the 1970s.
Their closest cousins are neutron stars, which are composed almost entirely of neutrons packed against each other, making them extremely dense. A neutron star has the same mass as the Sun but its diameter is only a few kilometers. Therefore, the escape velocity from their surface is close to the speed of light.
Not until the 1960s, when the first neutron...
Their closest cousins are neutron stars, which are composed almost entirely of neutrons packed against each other, making them extremely dense. A neutron star has the same mass as the Sun but its diameter is only a few kilometers. Therefore, the escape velocity from their surface is close to the speed of light.
Not until the 1960s, when the first neutron...
01:23Microtubule Formation
Microtubules are dynamic structures that undergo continuous assembly and disassembly. They originate from specialized multi-protein complexes known as microtubule organizing centers or MTOCs. Within the MTOC, the point of origin of the microtubule is known as the minus end, while the end radiating outward is the plus end. Microtubules serve two primary functions — the organization of spindle complexes to separate sister chromatids during mitotic or meiotic cell division and the formation of...
01:32Assembly of Complex Microtubule Structures
Complex microtubule structures are present in resting cells and in dividing cells. In resting cells, they are responsible for maintaining the cellular architecture, tracks for intracellular transport, positioning of organelles, assembly of cilia and flagella. They mediate the bipolar spindle assembly for chromosomal segregation and positioning of the cell division plate in dividing cells. The formation of microtubule complex structures depends on the cell type, cell stage, and cell function.
01:18Assembly of Cytoskeletal Filaments
Cytoskeletal filaments are polymeric forms of smaller protein subunits. However, individual cytoskeletal filaments may easily disassemble or associate with other similar filaments to form rigid structures. Microfilaments, made of actin monomers, rely on actin-binding proteins to form bundles and create networks of individual actin filaments. Microtubules rely on microtubule-associated proteins (MAPs) to form sturdy cylindrical structures. However, the proteins involved in forming complex...